"■'■■■ ■ . . ■ • • •' ■.. ' ' ■ :-.■■'••; '■■' 
 
 
 . Ji^Wi 
 
 
 Watchfulness 
 
 Hand-Picking 
 
 Insecticides 
 
 Ridding 
 the Garden 
 of Common 
 
 A. E. Micheibacher 
 John E.Swift 
 C.S. Davis 
 Dennis H. Hail 
 Robert D.Raabe 
 
 CALIFORNIA AGRICULTURAL 
 Experiment Station 
 
 
The Home Gardener 
 
 grows flowers for fun and vegetables for the family. But each year both fun 
 and family suffer because of the activities of numerous insect pests. 
 
 INSECTS and RELATED PESTS invade the garden from planting of the seed to har- 
 vesting of the crop. Many of them can be controlled quite easily. But to attempt 
 any control the gardener must 
 
 • Be able to identify the pests 
 
 # Hand-pick and destroy all pests found 
 9 Maintain clean cultural practices 
 
 <§; Have a basic knowledge of insecticides and what they will do 
 
 This circular is planned to help the home gardener in all four phases of his 
 pest-control problem. 
 
 PLANT DISEASES also invade the garden but many of them are not so easily con- 
 trolled as are the insects. In fact, for some diseases highly satisfactory control 
 measures are not yet known. The home gardener must control these largely by 
 prevention and not by remedy. 
 
 This circular presents a few suggestions for the control of the most common 
 diseases, and encourages the gardener to take a very practical view of the 
 disease problem. 
 
 JUNE, 1959' 
 
 The Authors: 
 
 A. E. Michelbacher is Professor of Entomology and Entomologist in the Experiment Station, 
 
 Berkeley. 
 John E. Swift is Extension Entomologist, Berkeley. 
 C. S. Davis is Extension Entomologist, Berkeley 
 Dennis H. Hall is Extension Plant Pathologist, Davis. 
 Robert D. Raabe is Assistant Professor of Plant Pathology and Assistant Plant Pathologist in the 
 
 Experiment Station, Berkeley. 
 
Danger 
 
 All insecticides are poisonous and must 
 be used with great caution. Some of the 
 most effective, such as parathion, Systox, 
 or TEPP are so dangerous that they cannot 
 be recommended for use in home gardens. 
 Some that can be used may be less hazard- 
 ous than others, but extreme care must be 
 exercised with all materials used in pest 
 control. 
 
 Here are precautions that must always be observed: 
 
 Keep insecticides in their original properly labeled containers. 
 
 Avoid pouring chemicals into a pop bottle or a similar vessel, and 
 never store chemicals in such a container. 
 
 Keep all insecticides and chemicals out of the reach of children. 
 
 Store preferably under lock and key, but at least place on high 
 shelves where children or pets cannot reach them. A dark storage 
 place is preferred, because any material which oxidizes will do 
 so more readily in sunlight. 
 
 Wash out empty containers and properly dispose of them through 
 burying or placing them in garbage can. 
 
 Avoid contamination of skin or clothing, particularly with undiluted 
 spray materials. After using insecticides, thoroughly wash the 
 hands and face with soap and water; a change of clothing is 
 advisable. 
 
 Avoid inhaling insecticides when handling, mixing, and applying 
 them. 
 
 Wash any piece of equipment thoroughly after using it. This in- 
 cludes mixing spoons and measures. Wash out sprayers with plenty 
 of water and place them on end to drain. 
 
 Read directions on container and note all the precautions given 
 before using the chemical. 
 
 Change immediately if spray is spilled on clothing, and wash or 
 bathe thoroughly. 
 
There 
 
 are 2 kinds 
 
 of insect pests 
 
 These two general groups are divided 
 by their method of feeding: chewing or 
 sucking. 
 
 CHEWING PESTS 
 
 Chewing pests are usually larger than 
 pests with sucking mouth parts. They 
 eat very noticeable holes in the parts 
 of the plant on which they feed, and 
 in some cases bore into the parts attacked. 
 This characteristic injury suggests the 
 best method of control. For the chew- 
 ing pests, use stomach poisons or 
 some of the newer insecticides that 
 exhibit both stomach and contact 
 action. 
 
 Chewing insects commonly found in 
 the home garden and covered in this cir- 
 cular are: ants, Brachyrhinus weevils, 
 bristly rose slug, bulb fly, cabbage 
 worms, corn earworm, cricket, cucumber 
 beetles, cutworms or armyworms, Euro- 
 pean earwig, flea beetles, grasshoppers, 
 hornworms, leaf miners, leaf tiers and 
 leaf rollers, pea weevil, root maggots, sod 
 webworms, or lawn moths, tomato pin- 
 worm, vegetable weevil, and wireworms. 
 
 Although they are not insects, the fol- 
 lowing pests have chewing habits and are 
 treated in the same way as insects: 
 garden centipede or garden symphylid. 
 land planarians, snails and slugs, sow- 
 bugs, pillbugs, and millipedes. 
 
 SUCKING PESTS 
 
 Sucking pests insert their mouth parts 
 into the plant tissue and suck the juice. 
 They may produce stunted or deformed 
 areas. The plant, if heavily infested, 
 gradually dries up. Some sucking insects 
 inject toxic materials into the plant and 
 others excrete quantities of honeydew 
 upon which the sooty mold fungus grows. 
 For the sucking insects use contact 
 insecticides and fumigants. 
 
 Sucking insects causing the home gar- 
 dener the most trouble, discussed in this 
 circular, are: aphids, harlequin cabbage 
 bug, leafhoppers, Lygus bugs, stinkbug. 
 mealybugs (aerial and soil), scales 
 (armored and unarmored) squash bug, 
 thrips, tomato psyllid, and whiteflies. Re- 
 lated sucking pests are spider mites or 
 red spiders, the tomato Russet mite, and 
 root knot nematode. 
 
Watch for pests . . . 
 
 . . . This is the first step in the successful 
 control of garden pests. 
 
 The gardener simply cannot plant 
 flowers or vegetables and go away and 
 leave them. A host of pests is waiting for 
 him to turn his back. 
 
 The watchful eye of the gardener — 
 frequently scanning the ground around 
 newly set plants, or checking the under- 
 side of leaves, or closely examining the 
 budding fruits and flowers — is the con- 
 trolling factor for which there is no sub- 
 stitute. Most destructive pests are small 
 and unless they are carefully looked for 
 may escape detection until they have 
 caused serious damage. Some insects feed 
 only at night. These are sometimes re- 
 vealed by examining the plants at night 
 with a flashlight. 
 
 Hand-pick the pests . . . 
 
 . . . and destroy all found. This is an old- 
 fashioned method of controlling insects. 
 Nevertheless, it still is effective in home 
 gardens against such pests as squash bug. 
 hornworms, leaf-feeding caterpillars, har- 
 lequin cabbage bug. snails, and slugs. 
 
 Maintain a clean culture . . . 
 
 . . . This step in pest control is frequently 
 overlooked. Remnants of plants should be 
 destroyed as soon as the harvest is com- 
 pleted. Weeds must not remain about a 
 garden since they serve as breeding 
 places for many insects and mites. Burn 
 or spade under rubbish piles and plant 
 refuse. 
 
 Use insecticides . . . 
 
 . . . Many times insecticides are the only 
 dependable means of holding the insects 
 under control. 
 
 Insecticides can be roughly divided 
 into three groups: stomach poisons, con- 
 tact insecticides, and fumigants. With 
 the advent of many of the new insecti- 
 cides this classification has lost much of 
 its meaning because a number of the 
 newer organic materials act as both 
 stomach and contact poisons; in addi- 
 tion, some exert a fumigant action. Insec- 
 ticides are continually being improved, 
 and recommendations for their use are 
 changing. For this reason it is important 
 to read carefully the directions given on 
 each new container you purchase, and to 
 follow them exactly. 
 
 [5] 
 
■ 
 
 How to use 
 
 STOMACH POISONS 
 
 Cryolite (sodium fluoaluminate ) , cal- 
 cium arsenate, and lead arsenate are 
 strictly stomach poisons. Each of these 
 has peculiarities which make it more, or 
 less, suitable for the job to be done. 
 
 Cryolite (sodium fluoaluminate) is 
 much less toxic to human beings and 
 other warm-blooded animals than either 
 calcium or lead arsenate, and is there- 
 fore recommended in preference to the 
 others for home vegetable gardens. 
 
 Calcium arsenate is extremely effec- 
 tive as a stomach poison for garden 
 pests — but unfortunately also for humans 
 and animals. The drift from this insecti- 
 cide, when used as a dust, has poisoned 
 animals that have eaten the contaminated 
 foliage and bees that have visited the 
 flowers. Also, it is injurious to the foliage 
 of certain plants. 
 
 Lead arsenate should never be ap- 
 plied to any vegetable crop or vegetation 
 if the foliage is intended for either human 
 or animal consumption. 
 
 DUST VEGETABLES 
 
 For vegetable gardens these stomach 
 poisons are probably most easily and 
 efficiently used as dusts. The following 
 rules will help you do a good job: 
 
 1 . Regulate dusting apparatus to pro- 
 vide a light and thorough coverage. 
 
 2. Emphasize light coverage. Never 
 overapply or pile the dust into the center 
 of the plants. Where the ground is well 
 covered with vegetation and the rows are 
 
 18 inches apart, use about V2 ounce of 
 dust to each 20 feet of row. 
 
 3. Apply dusts in early morning or 
 evening when there is little or no wind. 
 Drift of insecticides to other plants must 
 be reduced to a minimum. 
 
 Never allow poison dusts to drift to 
 adjoining property. 
 
 SPRAY CUT FLOWERS 
 AND ORNAMENTALS 
 
 Because flowering plants and orna- 
 mentals present only a slight problem of 
 poison residue, they may be successfully 
 sprayed. With this method of application 
 danger from drift is reduced. 
 
 Lead arsenate is probably the most 
 effective of the strictly stomach poisons 
 and is well adapted for use as a spray. 
 The standard spray mixture of this in- 
 secticide is V2 ounce of lead arsenate to 
 1 gallon of water. 
 
 The following suggestions apply to the 
 use of any spray material. 
 
 1 . Prepare a fresh batch of spray solu- 
 tion each time you spray the garden. Put 
 it in a clean applicator. Follow the in- 
 structions on the container. 
 
 2. Use a "sticker" or wetting agent, as 
 recommended by the manufacturer: or 
 use a paste-type oil emulsion. 
 
 3. Wet thoroughly all parts of the 
 plant when applying the spray. 
 
 4. Allow spray to dry before watering 
 plants. 
 
 5. Apply spray in early morning or 
 late evening; this is the best time to spray 
 
 STOMACH POISONS FOR CHEWING PESTS 
 
 T6] 
 
because of minimum wind. However, do 
 not apply sprays to plants heavily wet 
 with dew. 
 
 CONTACT INSECTICIDES 
 
 The contact insecticides include such 
 old standbys as nicotine and lime- 
 sulfur. 
 
 Pyrethrum and rotenone have be- 
 come well established over a number of 
 years. 
 
 Refined mineral oils are valuable in 
 killing insects, particularly when com- 
 bined with one of the organic insecti- 
 cides. 
 
 In addition to these there are a number 
 of new organic insecticides — organic 
 phosphates, organic thiocyanates, and 
 chlorinated hydrocarbons. Most of these 
 have complicated chemical names which 
 mean a great deal to the men in the 
 laboratory who discover and make them. 
 Their common names, however, are more 
 familiar to the home gardener. 
 
 These organics, using their more com- 
 mon designations, include: 
 
 Malathion, DDT, DDD, methoxy- 
 chlor, toxaphene, lindane (gamma 
 isomer of benzene hexachloride), 
 chlordane, dieldrin, aldrin, hepta- 
 chlor, Aramite, and Kelthane. 
 
 All of these compounds kill by contact ; 
 in addition, some of them may act as 
 stomach poisons. 
 
 The above-listed insecticides are sold 
 as commercial preparations either as 
 liquid concentrates or wettable powders 
 to use for spraying or dusting, or as pel- 
 lets, or in a granular form to be applied 
 by a duster or broadcast by hand. The 
 concentrated spray products should be 
 diluted with water and applied with 
 ordinary pressure sprayers. 
 
 Aerosol bombs designed for garden 
 
 spraying to wet the treated surface are 
 also available and can be effectively used 
 to control certain garden pests, especially 
 many of those infesting house plants. 
 
 SPECIFIC USES 
 
 Most insecticides or groups of insec- 
 ticides have specific uses or are especially 
 effective on certain pests or groups of 
 pests. 
 
 DDT, DDD, methoxychlor and lin- 
 dane are most effective on such chewing 
 pests as worms or caterpillars, beetles, 
 weevils, and against some sucking pests 
 such as thrips, leafhoppers, some aphids, 
 and Lygus bugs. Because of the relatively 
 long residual effect of these materials, 
 they should not be applied to vegetables 
 within three weeks of harvest. On certain 
 vegetables that cannot be washed or 
 wiped, applications should not be made 
 after the fruiting bodies begin to form. 
 These insecticides can be applied to flow- 
 ering plants at any time. 
 
 Chlordane, dieldrin, aldrin, and 
 heptachlor are effective against ants, 
 grasshoppers, earwigs, root maggots, 
 some weevils, wireworms, bulb fly, some 
 leaf miners, lawn moths, and certain 
 other pests. These materials should not 
 be applied to the edible portions of vege- 
 tables unless their residue can be removed 
 by washing, wiping, or stripping. They 
 should not be used on leafy vegetables 
 later than the seedling stage. 
 
 Malathion is effective against aphids, 
 spider mites, scale insects, mealybugs, 
 millipedes, and some of the other pests 
 previously mentioned. Its relatively short 
 residual action and low toxicity make its 
 use possible to within seven days of har- 
 vest. Malathion can be safely applied to 
 vegetables, flowering plants, and orna- 
 mentals at any stage of growth. This ma- 
 
 CONTACT INSECTICIDES FOR SUCKING PESTS 
 
 [7] 
 
terial is frequently used in combination 
 with other pesticides. 
 
 Aramite and Kelthane are known 
 as acaricides or miticides. These prod- 
 ucts are effective only on spider mites. 
 Aramite should not be applied to the 
 edible portion of any vegetable or fruit 
 crop. Both products can be used on most 
 ornamentals and flowering crops. Fre- 
 quently they are combined with other in- 
 secticides in order to control several pests 
 with one application. 
 
 Nicotine sulfate (Blackleaf 40), one 
 of the most common spray materials, is 
 particularly effective against aphids and 
 thrips. Nicotine is frequently used in 
 combination with other insecticides and 
 fungicides. 
 
 Pyrethrum and rotenone, when 
 used as sprays, are effective against 
 aphids, leafhoppers, thrips, and many 
 other soft-bodied insects. 
 
 Pyrethrum dusts should contain 
 0.10 to 0.25 per cent pyrethrins and 2 
 per cent organic thiocyanate applied at 
 temperatures below 65° F give excellent 
 control of leafhoppers, thrips, and cu- 
 cumber beetles. 
 
 Rotenone dusts containing at least 
 0.5 per cent rotenone are effective against 
 pea weevil, pea aphid, and small cabbage 
 worms. 
 
 The highly refined mineral oil emul- 
 sions are available alone or in combi- 
 nation with nicotine, pyrethrum, rote- 
 none, or with some of the new organic 
 insecticides. They are highly effective in 
 killing a wide range of insects including 
 certain aphids, scales, mealybugs, leaf- 
 hoppers, thrips, beetles, and caterpillars. 
 
 Nicotine, pyrethrum, rotenone, or- 
 ganic thiocyanates, mineral oils, and 
 malathion are relatively nontoxic to man 
 after they have been applied and then 
 allowed to "weather" for at least seven 
 days. They can be applied to most plants 
 at any stage of growth. 
 
 COMBINATION INSECTICIDES 
 
 The home gardener is most interested 
 in controlling a wide range of insects 
 with few applications. Many chemical 
 companies are now packaging combina- 
 tions of insecticides for the control of 
 numerous pests of both the sucking and 
 the chewing types. 
 
 Some of the combinations also include 
 fungicides to aid in the control of plant 
 diseases. Examples of these combined 
 products are: rotenone, pyrethrum, and 
 petroleum oil; petroleum oil, nicotine, 
 and DDT. Other combinations may con- 
 tain lindane, Malathion, DDT, or meth- 
 oxychlor; and fungicides such as captan, 
 zineb, ferbam, and ziram; or chlordane 
 and toxaphene; or dieldrin and lindane; 
 or dichloroethyl ether and lindane. 
 
 Numerous combinations are available, 
 and the gardener should compare them, 
 carefully reading labels and directions 
 before buying. 
 
 We cannot overemphasize the need to 
 follow directions on the package. Most 
 of the new products are continually un- 
 dergoing change as more about them is 
 learned through usage. Recommenda- 
 tions made by the manufacturer may 
 change for the same product over a 
 period of a few months. 
 
 Overapplication of insecticides should 
 be avoided. There is evidence that some 
 insecticides such as DDT and dieldrin 
 may accumulate in the soil, through pro- 
 longed use, to a level where they may 
 prove injurious to certain varieties of 
 plants that may be grown at a later date. 
 
 Another question is the danger of 
 destroying beneficial insects, particularly 
 bees, ladybird beetles, and other common 
 predators and parasites. 
 
 It is also possible that while these in- 
 secticides will kill certain insect pests, 
 they may actually encourage an increase 
 in other pests. In part this is brought 
 about by the destruction of natural 
 enemies. 
 
 [8] 
 
Also, some insecticides induce in- 
 creases in pest populations through phys- 
 ical or physiological processes. The 
 exact nature of these stimulations is not 
 as yet fully understood. 
 
 For example there is danger of serious 
 increases in the population of red spiders 
 where such materials as DDT, DDD, 
 dieldrin, heptachlor, and aldrin are used. 
 To combat this problem, many manu- 
 facturers are now adding sulfur to the 
 product, or a material such as Aramite 
 or Kelthane to destroy the developing 
 spider mite population. 
 
 The gardener can help to eliminate the 
 adverse effects of these insecticides by 
 using just enough and no more than is 
 
 necessary for adequate control. THIS IS 
 WHY DIRECTIONS ON THE PACK- 
 AGE MUST BE FOLLOWED. 
 
 FUMIGANTS 
 
 Fumigants are not widely used for the 
 control of insect pests in the home gar- 
 den. They are found practical only for 
 the control of certain underground pests. 
 
 Dichloroethyl ether is used for the 
 control of sod webworms, ground mealy- 
 bugs, and cabbage maggots. 
 
 Ethylene dibromide is very effective 
 for controlling wireworms, root weevils, 
 and the root-knot nematode. 
 
 Both of these fumigants are for sale in 
 small packages, and the directions for 
 their use are given on the containers. 
 
 EQUIPMENT 
 
 Sprayers. A satisfactory sprayer 
 breaks the liquid into a fine mist. Its 
 nozzle can be held at various angles in 
 order to wet the underside of foliage. In 
 the photo below — at left is a good type 
 sprayer for the fairly large garden ; it is 
 worn on the back of the operator and the 
 up and down motion of the handle cre- 
 ates pressure and works the agitator. At 
 
 suitable for large gardens. Pressure is 
 built up by pumping but there is no agi- 
 tator so material must be well mixed 
 before filling the sprayer. In the center is 
 a small atomizing type, good for house 
 plants and window boxes but too small 
 for general use. 
 
 At the top of page 10 appears a hose 
 attachment sprayer which is good for gen- 
 
 the right is a pressure-type sprayer also eral outside spraying. Liquid spray con- 
 
 
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 L> 
 
 
 B // m 
 
 wBl'-.; 
 
 ^l?WJB@8mS^M^.^^y' 
 
 
 
centrate is put in the jar, metered out and 
 diluted for proper rate of application by 
 water pressure from the hose. 
 
 Dusters. A good duster regulates the 
 flow of dust to avoid blobbing 
 
 It is un- 
 necessary to buy the most expensive 
 duster to get good performance. Photo 
 
 below shows: Top, small, inexpensive 
 dusters that are very efficient for use in a 
 small garden. Right, bellows type worn 
 on the back and suitable for very large 
 gardens where plants are continuous. 
 Left, rotary type carried in front of the 
 operator, also good for large gardens and 
 continous plantings. 
 
 
 [10] 
 
Most of the stomach poisons, and many 
 of the new insecticides, are extremely in- 
 jurious, or even fatal, if eaten by human 
 beings, livestock, cats, dogs, chickens, 
 and bees. They must be used with the 
 greatest possible caution. 
 
 Cryolite, calcium arsenate, DDT, 
 DDD, and lindane leave poison residues 
 which remain on the plant long after ap- 
 plication. If any of these chemicals has 
 been applied to edible portions of plants 
 (for instance, tomatoes), carefully wipe, 
 wash, or peel before serving. 
 
 On cauliflower, cabbage, lettuce, and 
 similar vegetables, do not use any of these 
 materials after the heads have begun to 
 form. On leafy vegetables that do not 
 head, these materials should not be ap- 
 plied after the plants are up and estab- 
 lished. 
 
 On beans, peas, squash, cucumbers, 
 and similar vegetables do not apply after 
 the fruit is set. 
 
 Lindane (gamma isomer of benzene 
 hexachloride) is an insecticide relatively 
 free of odor but one that must be used 
 with considerable caution because it may 
 impart an off flavor to certain vegetables. 
 
 In using poison bait, avoid scattering 
 the material on the plants, and keep con- 
 
 tainers out of reach of children and pets. 
 
 DDT and most other of the new or- 
 ganic compounds are poisonous to fish 
 and other cold-blooded animals. Avoid 
 spraying into lily pools, fish ponds, and 
 streams. Where insecticides might drip 
 into pools, cover the pools before spray- 
 ing. 
 
 In handling, mixing, and applying 
 poisonous insecticides, take special care 
 not to inhale the spray, or let it drip on 
 your clothes, hands, or arms. When the 
 job is finished, thoroughly wash the 
 hands as well as other parts of the body 
 which may have been exposed. If cloth- 
 ing is contaminated by an insecticide, 
 remove clothing, bathe, and do not wear 
 these garments again until they have been 
 thoroughly laundered. 
 
 Have a special storage place for cans 
 and packages of materials so that they 
 can be kept out of reach of children and 
 pets. Be certain that all containers are 
 labeled. Keep the storage place locked. 
 
 A dark storage place is preferred, be- 
 cause any material which oxidizes will 
 do so much more readily in sunlight. 
 
 After using any piece of equipment, 
 wash it thoroughly. Wash mixing spoons 
 and containers. Invert sprayer to drain. 
 
 [ii 
 
CONTENTS 
 
 Chewing Pests 
 
 Ants 13 
 
 Brachyrhinus weevils 13 
 
 Bristly rose slug 14 
 
 Bulb fly 15 
 
 Cabbage worm 16 
 
 Corn earworm 16 
 
 Cricket 17 
 
 Cucumber beetles 17 
 
 Cutworms or armyworms 18 
 
 European earwig 19 
 
 Flea beetles 19 
 
 Garden centipede or garden symphylid . 20 
 
 Grasshoppers 20 
 
 Hepialid moth 21 
 
 Hornworms 21 
 
 Land planarians 21 
 
 Leaf miners 22 
 
 Leaf tiers and leaf rollers 22 
 
 Millipedes 23 
 
 Pea weevil 23 
 
 Root maggots 24 
 
 Snails and slugs 24 
 
 Sod worms or lawn moths 25 
 
 Sowbugs and pillbugs 26 
 
 Tomato pinworm 27 
 
 Vegetable weevil 27 
 
 Wireworms 28 
 
 Sucking Pests 
 
 Aphids 28 
 
 Harlequin cabbage bug 29 
 
 Leafhoppers 29 
 
 Mealybugs (aerial) 30 
 
 Mealybugs (soil) 31 
 
 Scales (armored) 31 
 
 Scales (unarmored) 32 
 
 Spider mites or red spiders 33 
 
 Squash bug 34 
 
 Thrips 34 
 
 Tomato psyllid 35 
 
 Tomato russet mite 35 
 
 Whiteflies 36 
 
 Root-knot nematode 37 
 
 Diseases 
 
 Soil-borne diseases 38 
 
 Damping-off diseases 38 
 
 Water mold root rot 39 
 
 Armillaria root rot 39 
 
 Verticillium wilt 40 
 
 Salt damage 41 
 
 Mineral deficiency diseases 41 
 
 Stem, foliage, and flower 
 
 diseases (powdery mildew) 42 
 
 Sunburn 43 
 
 Rust diseases 43 
 
 Twig dieback of rose 44 
 
 Anthracnose of sycamore 44 
 
 Scorch of Modesto ash 44 
 
 Fire blight 44 
 
 Peach leaf curl 45 
 
 Iris leaf spot 46 
 
 Virus diseases 46 
 
 [12] 
 
Chewing Pests 
 
 The Pests 
 
 ANTS 
 
 Ants are social insects, living in 
 colonies, that are found nearly every- 
 where. Depending upon the species, they 
 build their nests in open ground, under 
 stones or wood, in wood or decaying 
 trees, or in any other location that offers 
 protection. 
 
 Ants are generally wingless except at 
 mating time. At that period swarms of 
 recently emerged winged males and fe- 
 males can be seen. Soon after mating the 
 males die and the females or queens lose 
 their wings. At this time the females at- 
 tempt to establish new colonies. 
 
 Feeding habits vary with the species. 
 Some feed on crops, fruits, seeds, nuts, 
 and fungi. Others feed upon the exudate 
 given off by plants or the honeydew ex- 
 creted by certain insects. Those that feed 
 on honeydew protect the insects that 
 produce it. Still others feed upon the 
 bodies of insects, small animals which 
 they attack, or upon dead animals. 
 
 Ants may injure lawns, gardens, and 
 orchards by their nesting habits. Some 
 species are attracted into a house by the 
 presence of sweets or fatty substances. 
 
 The most annoying ant in California is 
 the Argentine ant, Iridomyrmex humilis 
 Mayr, which has spread over most of the 
 state since first found in 1905. It is very 
 aggressive and, where strongly estab- 
 lished, has driven out and largely re- 
 placed many of the native species. 
 
 The preparation of this section was made pos- 
 sible through the splendid help of E. O. Essig, 
 Professor of Entomology and Entomologist in 
 the Experiment Station, Emeritus, who not only 
 furnished much of the subject matter, but also 
 numerous photographs. 
 
 CONTROL: A number of insecticides 
 are extremely effective. The two most 
 effective are chlordane and dieldrin. Lin- 
 dane is also effective and is sometimes 
 available in combination with chlordane 
 or dieldrin in commercial mixtures. 
 These are available as dusts, sprays, and 
 granules. 
 
 The satisfaction obtained with these 
 materials is dependent upon the 
 thoroughness with which they are ap- 
 plied. In making applications follow 
 carefully the directions given on the con- 
 tainers. 
 
 The red harvester ant is also a problem 
 in some of the drier regions. It can 
 destroy garden plants as well as inflict 
 painful stings. These ants are best con- 
 trolled by dusting or spraying dieldrin 
 or chlordane over the entrance to the nest 
 and working it into the soil. 
 
 BRACHYRHINUS WEEVILS 
 
 Several species of Brachyrhinus wee- 
 vils are very destructive to garden plants. 
 The adults, depending upon the species, 
 are shiny brown to nearly black and 
 measure in length from about V± to a 
 little more than % inch. They are true 
 weevils, with heads terminating in a 
 blunt snout. The larvae are white, cres- 
 
 Both larvae and adults of Brachyrhinus weevils 
 attack many ornamentals. 
 
 [13] 
 
cent-shaped, legless grubs with brown 
 heads; they are about J /2 inch long when 
 mature. 
 
 Both the adults and larvae are destruc- 
 tive. The adults feed at night and hide 
 during the day. Their typical way of 
 feeding is to eat out notches along the 
 edge of leaves. The larvae live in the soil 
 and damage plants by feeding on the 
 roots, underground stems, and the bark 
 of the trunk just below ground level, thus 
 girdling the plants. Plants attacked and 
 often killed include bush berries, straw- 
 berries, begonias, cyclamen, privet, many 
 ornamentals such as camellias, rhododen- 
 drons, azaleas, primroses, and wistarias. 
 
 CONTROL: This is directed mainly 
 against the adults, before they have had 
 opportunity to lay eggs. The new genera- 
 tion of adults usually makes its appear- 
 ance in late April or May. At this time 
 many can be killed by poison bait scat- 
 tered in the garden. The most effective 
 bait is a proprietary one consisting of a 
 poison on dried apple pulp. The bait 
 should be scattered at the rate of from 
 50 to 75 pounds to the acre or 1.25 to 2.5 
 pounds per 1,000 square feet of garden. 
 Although not so effective, a substitute 
 bran bait containing sugar, and poisoned 
 with calcium arsenate or sodium fluo- 
 silicate can be used. 
 
 DDT, applied in a spray or as a 5 per 
 cent dust, is an effective treatment which 
 is used against the adult weevils. Infested 
 plants can be sprayed or dusted, or the 
 soil beneath the plants can be treated. 
 Treatment should be timed in early 
 spring when the adults are emerging 
 from the soil but before they have had 
 opportunity to lay eggs. Follow the direc- 
 tions given on the package and use care 
 not to contaminate vegetation meant for 
 human or animal consumption. 
 
 If Brachyrhinus weevils are a continu- 
 ous pest, it is best to treat the soil with 
 chlordane, aldrin, dieldrin, or heptachlor 
 before planting. Apply one such insecti- 
 cide in sufficient water to treat 1,000 
 square feet: chlordane, ^2 pound wet- 
 table powder or 1 pint 50 per cent emul- 
 sion; aldrin or heptachlor % pint 25 per 
 cent emulsion; or dieldrin, V 2 pint of 15 
 per cent emulsion. If applied thoroughh 
 and worked into the soil for 6 to 8 inches 
 these materials will control larvae of the 
 weevils for two to three years. 
 
 BRISTLY ROSE SLUG 
 
 r> „ j.ni 
 
 The pale green bristly rose slug is a pest of 
 almost every rose garden. 
 
 The adult of the bristly rose slug is a 
 small black sawfly which is related to 
 bees and wasps. It is about % inch long, 
 and lays its eggs in grooves in the midribs 
 of the leaves. The caterpillar-like larvae 
 are pale green, and when full grown 
 measure about % inch in length. All in- 
 jury is done by the larvae. They are 
 found on the underside of the leaves 
 which they first skeletonize; later they 
 eat holes into or entirely devour the 
 leaves. There are at least two generations 
 
 STOMACH POISONS FOR CHEWING PESTS 
 
 I 14] 
 
of slugs a year and the adults first appear 
 in April or May. If not controlled, the 
 pest may defoliate roses. 
 
 CONTROL: This should start as soon 
 as injury to the plant is noted. The pest 
 is easily controlled with a spray or dust 
 of any of the common stomach poisons. 
 It is also controlled with DDT or DDD, 
 methoxychlor, or lindane, but to avoid a 
 serious increase in red spiders these in- 
 secticides should be used in combination 
 with sulfur or Kelthane. Most of the con- 
 tact insecticides are effective in killing 
 the rose slug if the pest is contacted with 
 the material. Even nicotine is effective if 
 applied when the larvae are tiny. 
 
 BULB FLY 
 
 Careful selection of firm bulbs is the best pro- 
 tection from the bulb fly maggot. 
 
 The bulb fly is a large hairy black fly, 
 marked with gray, yellow, or orange, and 
 is about % to % inch long. It greatly 
 resembles and acts like a small bumble- 
 bee. The eggs are small, oval, white, and 
 are laid near the surface of the soil close 
 
 to the crown of the host plant. The mag- 
 gots when mature are robust, measure 
 V2 to % inch in length, and are white, 
 yellowish, or brown. 
 
 The young maggots bore into the bulb 
 and feed upon the tissue with their strong 
 hooked mouth parts. This usually results 
 in hollowing out the center of the bulb, 
 or reducing it to a thick brown excre- 
 mentaceous mass. Usually only a single 
 maggot is found in a bulb. Narcissus 
 bulbs are preferred, but amaryllis, hya- 
 cinth, eurycles, galtonia, habranthus, 
 hippeastrum, lilies, tulips, and vallota are 
 attacked. Infested bulbs can be detected 
 by pressing to determine their solidity. 
 
 CONTROL: This is a difficult problem 
 for the home gardener. Every attempt 
 should be made to select and plant bulbs 
 that are firm and free from maggots or 
 injury. Commercial control is obtained 
 by treating harvested bulbs in hot water 
 for 2 hours at 110° F. The temperature 
 must be accurately controlled because a 
 temperature rise of a degree or two even 
 for a short period is likely to injure the 
 bulbs seriously. Field control is possible. 
 Some relief ordinarily can be secured by 
 treating the plants and the soil about 
 them, following the blooming period, 
 with sprays or dusts containing chlor- 
 dane, dieldrin, heptachlor, or aldrin. Be- 
 cause the flight period of the adults lasts 
 through late spring and early summer 
 a second treatment in late May and early 
 June may be desirable. Treating the 
 bulbs with a chlordane or heptachlor dip 
 for 10 minutes before setting out the 
 bulbs results in excellent control of the 
 pest. A chlordane dip should contain 1% 
 ounces of an emulsifiable concentrate 
 containing 4 pounds of chlordane per 
 gallon in 1 gallon of water. A 2 pound 
 per gallon emulsifiable heptachlor con- 
 
 CONTACT INSECTICIDES FOR SUCKING PESTS 
 
 [15] 
 
centrate should be used at the rate of 0.6 
 ounce per gallon of water. To prevent 
 the spread of basal rot, add sufficient 
 Cercsan to make a 2 per cent mixture. 
 
 CABBAGE WORMS 
 
 Cabbage worms include three kinds 
 that seriously injure cabbage and related 
 plants : ( 1 ) The cabbage worm is the im- 
 mature form of a white butterfly with 
 dark markings; it is uniformly velvety 
 green and, when full grown, is about 1 
 inch long. (2) The cabbage looper — the 
 caterpillar stage of a moth — is light 
 green, with several longitudinal fine 
 white stripes running the length of the 
 body. It grows to a length of about 1 
 inch. In crawling it loops its body — 
 hence the name. (3) The caterpillar of 
 the diamond-back moth is light green. It 
 is the smallest worm attacking cabbage; 
 when full grown it measures about V' 
 inch. 
 
 All three species eat irregular holes in 
 the leaves of cabbage and related plants: 
 in heavy infestations the plant is left 
 worthless. 
 
 Control: During early stages of plant 
 growth, dust with DDT, DDD, or calcium 
 arsenate. Do not use these above-named 
 poisons after the edible parts of the plant 
 have started to form; instead, thoroughly 
 apply a dust containing at least 0.50 per 
 cent rotenone, or a rotenone dust corn- 
 
 Cabbage worms must be controlled during 
 early stages of plant growth. 
 
 bined with pyrethrum, nicotine, or or- 
 ganic thiocyanate, or a spray or dust 
 containing malathion. This latter insecti- 
 cide should not be applied within a week 
 of harvest. For satisfactory results, all 
 of these materials should be applied be- 
 fore the worms are large. Destroy cab- 
 bage and related plants as soon as harvesl 
 of that crop is completed. The worms 
 attacking this group of plants are most 
 serious in summer and fall. 
 
 CORN EARWORM 
 
 The corn earworm is about 1% inches 
 long when fully grown. It ranges from 
 green to almost black and may be marked 
 with longitudinal stripes of various 
 colors. It is principally a pest of fruiting 
 bodies, into which it bores. It is the 
 common worm found eating its way down 
 through the kernels of the ears of corn. 
 Also a serious pest of tomatoes, it usually 
 enters at the stem end and consumes the 
 inside of the fruit. It also attacks beans 
 and many other crops and weeds. 
 
 There are no less than three genera- 
 tions in a year. The adult moths become 
 active at about dusk, at which time 
 females may be seen flitting here and 
 there, laying eggs on their host plants. 
 The eggs are laid mainly on the silk of 
 sweet corn, while on other crops, such 
 as tomatoes and beans, they are laid on 
 the outer portion of the plant. The eggs 
 are laid singly. They are pearly white 
 when first laid but darken as they ap- 
 proach the hatching of the young cater- 
 pillars. 
 
 CONTROL: On corn, the corn ear- 
 worm mav be effectivelv controlled with 
 a 5 per cent DDT dust. The DDT should 
 be applied to the silk with a brush. The 
 brush is dipped into the DDT. then 
 pressed against the silk and given a twist 
 to force the dust into the entrance of the 
 silk channel. Treatment should be started 
 within three davs after the silk appears, 
 and repeated at least three times at three- 
 day intervals. Each ear should be treated 
 every time. Because of the residue from 
 
 [16 
 
The corn earworm not only likes corn, but will 
 invade the tomato patch. 
 
 DDT, do not feed corn stalks to animals 
 if DDT has been used. Another method of 
 control is by injecting directly into the 
 silk channel 1 cubic centimeter (about 
 !/4 teaspoon) of a highly refined mineral 
 oil, which contains 0.2 per cent pyreth- 
 rins. You can purchase this mixture 
 from dealers handling insecticides. Oil 
 interferes with fertilization; therefore, 
 should be applied only after the silk has 
 begun to wilt and turn brown. Use a 
 plunger type of oil can. A setscrew at- 
 tachment can be fitted to the plunger to 
 regulate the amount of oil ejected with 
 each stroke. Insert the nozzle of the oil 
 can not more than % inch into the silk 
 channel. For small plantings an ordinary 
 medicine dropper can be used. Control 
 can also be obtained by clipping off the 
 tips of the ears to remove the entering 
 worms. This should not be done until 
 pollination is complete. Destroy clipped 
 tips. 
 
 On tomatoes, dust the plants lightly but 
 thoroughly as necessary with DDT, DDD, 
 or calcium arsenate. However, do not use 
 DDT on tomatoes grown under glass. If 
 treatment is required during the harvest 
 season, wash or carefully wipe the fruit 
 
 lo remove any poison residue. ( See to- 
 mato mite.) 
 
 CRICKET 
 
 The common field cricket is a large, 
 brown to black, swift-moving insect with 
 long feelers. Nocturnal in habits, the 
 cricket breeds in uncultivated areas; in 
 high populations they may migrate to 
 gardens in sufficient numbers to do some 
 damage. The cricket feeds on foliage and 
 with certain plants, such as tomato, at- 
 tacks the fruit as it begins to ripen. 
 
 CONTROL: The cricket is most suc- 
 cessfully controlled with insecticides that 
 contain dieldrin, heptachlor, or chlor- 
 dane. Avoid applying these insecticides 
 to parts of plants intended for human 
 consumption, unless the residue can be 
 removed by washing, wiping, or strip- 
 ping. In applying the materials, carefully 
 follow the directions given on the con- 
 tainer label. Pellets or granules of these 
 materials spread in and around the 
 garden are also effective in controlling 
 this insect. These do not leave a harmful 
 residue problem of spray or dust. Even 
 so, care should be exercised to see that 
 they are not directly applied to edible 
 portions of plants. Baits made of these 
 materials are also effective but are limited 
 in usage because they are attractive to the 
 pest only while moist. Again avoid apply- 
 ing bait to edible parts of plants. 
 
 CUCUMBER BEETLES 
 
 The western spotted cucumber beetle 
 (or Diabrotica) is small and green, with 
 twelve black spots on the wing covers. 
 It is widespread throughout California 
 and attacks most vegetables and many 
 flowering plants, but particularly cucum- 
 bers, squash, melons, beans, corn, and 
 similar crops. The whitish, wormlike 
 larvae feed on the roots; the adults on the 
 leaves, stems, and floral parts. A close 
 relative, the striped cucumber be:tle, is 
 somewhat smaller. It is yellowish with 
 three black lines down its back. It seri- 
 
 [17] 
 
This small green cucumber beetle with its black 
 spots is to be found in most gardens. 
 
 ously attacks cucurbits (squash, melon, 
 and the like) . 
 
 CONTROL: When there is no residue 
 problem, cucumber beetles can be con- 
 trolled by thoroughly dusting the plants 
 with DDT, malathion, dieldrin, hepta- 
 chlor, or aldrin. However, DDT, dieldrin, 
 aldrin, and heptachlor may occasionally 
 cause some injury to certain varieties of 
 squash. When a residue problem is in- 
 volved, use malathion as a dust or a 
 spray. 
 
 The use of DDT, dieldrin, heptachlor, 
 aldrin, and chlordane is likely to result in 
 a serious increase of red spiders. The ad- 
 dition of sulfur to the commercial dust 
 will help to suppress red spiders but be- 
 cause of the danger of injury do not use 
 it on melons or strawberries. 
 
 CUTWORMS or ARMYWORMS 
 
 Cutworms or armyworms are the cater- 
 pillars of moths. When full grown they 
 are 1% to 2 inches long. Most species are 
 somber in color, although some, such as 
 the western yellow-striped armyworm, 
 are rather showy. Cutworms attacking 
 vegetables may be divided into two 
 groups: (1) those feeding at night and 
 hiding during the day in the soil and 
 debris, and (2) those spending their 
 entire larval life on the plant and feeding 
 in the daytime. 
 
 Cutworms cause injury by cutting off 
 seedlings or newly transplanted plants 
 below or above the ground, or by eating 
 
 large, irregular holes in the leaves or 
 fruiting bodies of older plants. 
 
 CONTROL: Cutworms belonging to 
 group 1 can be controlled with commer- 
 cially prepared poison baits. Scatter the 
 bait over the infested area just before 
 dusk. To control cutworms belonging to 
 group 2, dust the plants thoroughly with 
 DDT, DDD, toxaphene, cryolite, or cal- 
 cium arsenate. Where seedling stands are 
 being injured by worms of either group, 
 dust with lindane, DDD, DDT, or toxa- 
 phene. Do not use toxaphene on melons 
 or squash. The use of DDT, DDD, or 
 toxaphene may result in a serious in- 
 
 This cutworm is typical of the group that feeds 
 at night and hides during the day. 
 
 The yellow-striped armyworm is one of the cut- 
 worms which feed during the day. 
 
 [18] 
 
crease of red spider. The addition of ^4 
 to y 2 by volume of sulfur to the dust will 
 help control this pest. Note precautions 
 given for poison residues. 
 
 EUROPEAN EARWIG 
 
 The European earwig is a dark chest- 
 nut-brown insect about % inch long, 
 with a pair of forceps on the rear end of 
 the body. Although provided with short 
 wings, it usually runs. It feeds at night, 
 and hides by day under boards, rocks, 
 rubbish, and in crevices. It attacks many 
 different kinds of vegetables, fruits, and 
 flowering garden plants, eating holes in 
 leaves and flowers. It is an introduced 
 species not yet spread throughout the 
 state, and is most destructive in the cooler 
 coastal regions. Eggs are laid from De- 
 cember through February, and the pest is 
 most destructive from April through July. 
 
 CONTROL: To control the European 
 earwig, use a poison bait containing 
 bran, sodium fluosilicate, and fish oil. 
 Commercial prepared baits are available. 
 Baits are most effective when used during 
 April to July inclusive and should be ap- 
 plied in the evening. The bait should be 
 scattered over areas frequented by the 
 pest but it must be kept off the plants. 
 
 Since it is poisonous, it should be kept 
 away from animals. 
 
 A dust containing chlordane, lindane, 
 dieldrin, aldrin, or hepiachlor is effective. 
 Apply dusts around the hiding places of 
 the earwig particularly along fences and 
 house foundations. 
 
 Avoid dusting the shrubbery heavily 
 with DDT, dieldrin, aldrin, and hepta- 
 chlor; these chemicals are known to kill 
 beneficial insects that help to control 
 other pests. Some insecticides such as 
 dieldrin, heptachlor, and chlordane are 
 prepared in granular form, which greatly 
 facilitates their application and prevents 
 serious contamination of foliage. When 
 spread over the ground area where the 
 earwigs hide these insecticides are very 
 effective. Avoid applying granules to 
 edible parts of plants. 
 
 FLEA BEETLES 
 
 Flea beetles are small and are black, 
 brown, greenish, or yellowish. Most of 
 them are only about % 6 inch long. They 
 jump like fleas and eat small holes in 
 leaves. Many species attack vegetables. 
 Where infestations are heavy, plants may 
 be nearly defoliated. Seedlings or newly 
 transplanted plants are likely to be most 
 seriously injured. The minute wormlike 
 grubs feed upon roots and tubers of cul- 
 tivated and wild plants. 
 
 t ** 
 
 Great numbers of earwigs may be found 
 under boards or rubbish, and should be baited, 
 or the infested area dusted. 
 
 Tiny flea beetles eat small holes in leaves and 
 can defoliate a plant. 
 
 [19] 
 
CONTROL: To control flea beetles, 
 dust the infested plants evenly and 
 thoroughly with DDT, lindane, methoxy- 
 chlor, dieldrin, aldrin, heptachlor, cryo- 
 lite, or calcium arsenate. Where a residue 
 problem is involved, use 0.75 per cent 
 rotenone dust. 
 
 Note precautions on page 3. 
 
 GARDEN CENTIPEDE or 
 GARDEN SYMPHYLID 
 
 (Not an insect but has chewing habits 
 and is controlled by the same methods 
 used for chewing insects.) 
 
 The adult of the garden symphylid — 
 which is centipede-like in appearance — 
 measures about ^4 mcn m length. They 
 are delicate and a uniform light cream 
 color except for a darker streak caused 
 by the contents of the digestive tract. The 
 garden centipede lives in the soil, is rapid 
 in movement, and may penetrate the soil 
 to a depth of 3 feet or more. They feed 
 on the roots and tubers of most plants 
 and, under moist conditions, may come to 
 the surface of the soil and feed on the 
 under surfaces of leaves that are in con- 
 tact with the soil. Where abundant they 
 may destroy germinating seeds and trans- 
 plants and seriously attack the roots of 
 established plants. Where this latter situa- 
 tion occurs the infested plants may be 
 stunted and show lack of vigor. 
 
 CONTROL: Because they live in the 
 soil, the garden centipede is difficult to 
 control. Some relief can be obtained by 
 spreading lindane over the soil and work- 
 ing it in to a depth of 6 inches. The treat- 
 ment is best applied two to three weeks 
 before planting. Lindane must be used 
 with some caution because it imparts an 
 off-flavor to some crops, such as potato 
 and root crops. 
 
 Some suppression of the garden centi- 
 pede or garden symphylid population can 
 also be secured where capsules of ethy- 
 lene dibromide are used as a soil fumi- 
 gant. These are commercially available, 
 
 and the directions given on the package 
 should be followed carefully. 
 
 The garden centipede is unable to make 
 its own runways and for this reason firm- 
 ing the soil about transplants helps in 
 getting the plant established. 
 
 GRASSHOPPERS 
 
 Grasshoppers are familiar garden pests 
 in the warm interior areas of California. 
 The young are much like the adults except 
 that they do not have fully developed 
 wings. In growing they cast their skin a 
 number of times. With each cast they 
 gain in size and the wings become more 
 apparent. The fully developed adult ap- 
 pears after the final molt. Eggs are laid 
 in the soil but do not hatch until the 
 following spring. 
 
 Both young and adults attack plants. 
 Young plants may be eaten off. When in- 
 festations are severe, large plants are de- 
 foliated and even the tender bark may be 
 eaten from trees and ornamentals. 
 
 CONTROL: Grasshoppers are con- 
 trolled by scattering commercially pre- 
 pared poison bait lightly over the infested 
 area in early morning. Repeat the opera- 
 tion at intervals of a few days to a week 
 until the pest is eliminated. Dieldrin, al- 
 drin, heptachlor, lindane, and chlordane 
 dusts or sprays are effective. 
 
 <0fr 
 
 ^ : ^ v >: - : 
 
 mm 
 
 »* 
 
 nv 
 
 • -x 
 
 Grasshoppers feed on vegetables as well as on 
 the leaves and tender bark of many plants. 
 
 20] 
 
HEPIALID MOTH 
 
 The larvae of this moth when mature 
 measure about IV2 inches in length. They 
 attack the roots of many ornamentals 
 and in the region adjacent to the San 
 Francisco Bay rank as one of the most 
 destructive pests of garden plants. Their 
 damage to plants is often attributed to 
 other soil-infesting insects, such as the 
 larvae of Brachyrhinus weevils. The 
 larva of the hepialid moth eats, girdles, 
 and bores through roots and the crown 
 of plants below the soil surface. Among 
 the plants that may be attacked and fre- 
 quently killed are azalea, camellia, rho- 
 dodendron, rose, and many other plants. 
 
 CONTROL: Despite the serious and 
 widespread damage done by the pest, 
 little is known about its control. Spray- 
 ing the base of plants with DDT might 
 give some relief, but to the present time 
 no experimental data support this con- 
 tention. 
 
 HORNWORMS 
 
 Hornworms (tomato and tobacco) 
 are caterpillars of the large "sphinx" or 
 "hummingbird" moths. When fully grown 
 they are nearly 4 inches long. They are 
 predominantly green, with white diag- 
 onal stripes, and with a characteristic 
 spine (horn) at the rear end. They are 
 serious pests of tomato, on which they 
 feed upon the vine, blossoms, and fruit. 
 Hornworms are most destructive in the 
 warm interior valleys. If left unchecked 
 they may completely defoliate plants. 
 They also attack potatoes, eggplant, and 
 
 peppers. A favorite wild host is the Jim- 
 son weed. 
 
 CONTROL: These are controlled best 
 by hand-picking and destroying them as 
 soon as they are seen. They are found 
 most easily in early morning, when feed- 
 ing is confined largely to the outside of 
 the vine. 
 
 DDD, DDT, or calcium arsenate dusts 
 are effective. Dusting must be light but 
 thorough. If the application is made dur- 
 ing the harvest period, wash or carefully 
 wipe the tomatoes, eggplants, or peppers 
 to remove any poisonous residue. On to- 
 matoes, if the tomato mite is present, use 
 a dust containing 50 to 75 per cent sulfur. 
 
 LAND PLANARIANS 
 
 (Not an insect but has chewing habits.) 
 
 Along the coastal areas of middle and 
 northern California and particularly in 
 the San Francisco Bay region, there are 
 two species of these peculiar, shiny flat- 
 worms that somewhat resemble slugs ex- 
 cept that they are much more slender, 
 flatter, and do not have horns. Like slugs, 
 they travel on a slime path. The larger of 
 these is a yellowish species which may 
 attain a length of 3 inches, and the 
 smaller one is black and only about 1% 
 inches long when mature. They are most 
 often found feeding on and in the fruit 
 of strawberries of which they are very 
 fond. Under moist conditions they may 
 become numerous and do much damage. 
 
 CONTROL: Less frequent watering 
 helps to reduce their numbers. They dis- 
 appear as summer approaches. 
 
 The big green 
 hornworm enjoys 
 vegetables. He 
 can be found 
 most easily in 
 early morning on 
 tomato, pepper 
 plants, eggplant. 
 
LEAF MINERS 
 
 Many kinds of leaf miners attack vege- 
 tables, flowering plants, and ornamentals. 
 Most leaf miners are the larvae of flies. 
 When hatched from eggs which have been 
 laid on the surface of the plants, the min- 
 ers, or small maggots of the spinach leaf 
 miner, enter the leaf tissues and feed be- 
 tween the two surfaces. They cause large, 
 colorless blotches or mines. Where nu- 
 merous they may destroy the entire leaf. 
 On holding infested leaves to the light, 
 you can easily see the maggots in the 
 mines. 
 
 The beet or spinach leaf miner is whit- 
 ish and when full grown is nearly % inch 
 long. Spinach, beet, and chard are among 
 the plants seriously injured. 
 
 Numerous other leaf miners attack gar- 
 den plants. These are much smaller than 
 the spinach leaf miner. The adult flies in- 
 sert their eggs into the leaf surface and, 
 on hatching, the larvae or maggots make 
 a serpentine type of mine in the leaves. 
 Under conditions of severe infestation 
 plants may be defoliated. 
 
 CONTROL: Late fall and winter-grown 
 crops usually escape injury from leaf 
 miners. Spring and summer crops are 
 sometimes seriously attacked. Control of 
 leaf miners with insecticides is difficult. 
 The most effective materials are dieldrin, 
 heptachlor, and aldrin. Because of a resi- 
 due problem these materials cannot be 
 used on leafy vegetables, especially spin- 
 ach. However, they can be applied to to- 
 
 mato and eggplant, and to flower plants 
 and ornamentals at any time. When a res- 
 idue problem is involved on edible plants, 
 a nicotine spray containing 1 teaspoon of 
 nicotine sulfate and 2 tablespoons of soap 
 to 1 gallon of water, if applied frequently, 
 is partially effective. 
 
 LEAF TIERS and LEAF ROLLERS 
 
 The adults are small, somber-colored 
 moths that measure about % inch in 
 length when at rest. Depending upon the 
 species the caterpillars are various shades 
 of yellow, tan, or green with amber-col- 
 ored heads. When mature the caterpillars 
 are about % incn in length. According to 
 the species involved, they feed within 
 leaves that are tied together with webbing 
 or in a leaf-fold that is held in place by 
 webbing. Besides feeding on the leaves, 
 they attack developing buds and fruiting 
 bodies. The caterpillars of leaf rollers 
 wriggle violently backward when dis- 
 turbed. They move into their leaf-roll 
 shelters or they may drop to the ground 
 on a silken thread. 
 
 Upon reaching maturity the caterpil- 
 lars pupate within the parts of the plant 
 that have been webbed together. After a 
 period of time the adults emerge and, ac- 
 cording to the species, lay eggs singly or 
 in batches either on the stems or more 
 often on the undersides of the leaves. 
 
 CONTROL: Best results with insecti- 
 cides are obtained if treatments are ap- 
 plied while the caterpillars are still small. 
 
 The colorless area in the leaf at the left is caused by leaf miners which feed between the two 
 leaf surfaces. At right the mining operations are exposed. 
 
 [22] 
 
Insecticides containing DDT, DDD, lin- 
 dane, cryolite, pyrethrum, malathion, or 
 a combination of these materials should 
 effectively control the pest. 
 
 MILLIPEDES 
 
 (Not an insect but has chewing habits.) 
 
 Millipedes are long, wormlike animals 
 related to centipedes, but differing from 
 centipedes in that they have two pairs of 
 legs on each body segment, except for the 
 first three segments behind the head. The 
 common forms, found in gardens, have 
 hard bodies, measure from % to 1 inch 
 long, and are dark brown or cream- 
 colored. The bodies of some species are 
 round — others are somewhat flattened. 
 They are active at night but during the 
 day they hide in secluded locations, un- 
 der boards, rocks, and flats. If their hid- 
 ing places are disturbed they can often be 
 seen coiled in a very characteristic man- 
 ner. 
 
 Millipedes like damp locations and are 
 found in greatest abundance in moist 
 spots that are rich in organic matter. 
 Their food is supposed to consist of de- 
 caying vegetation, although where they 
 are extremely abundant, they may feed 
 on growing vegetation. On occasions, 
 they have been known to feed on sprout- 
 ing seeds, tubers, and bulbs. 
 
 CONTROL: Control measures are sel- 
 dom justified unless millipedes are pres- 
 ent in large numbers. Dust or sprays con- 
 taining DDT, chlordane, dieldrin, mala- 
 thion, lindane, or combinations of these 
 materials are partially effective in con- 
 trolling the pest. 
 
 These materials should be used accord- 
 ing to the manufacturer's recommenda- 
 tions, and should be applied to the areas 
 frequented by millipedes. Although the 
 treatment is rather expensive, millipedes 
 can be controlled by thoroughly wetting 
 the soil about the infested plants with a 
 40 per cent nicotine sulfate solution, di- 
 luted at the rate of 2 teaspoons to the 
 gallon of water. 
 
 PEA WEEVIL 
 
 The pea weevil is a short, chunky 
 beetle about % inch long. The base color 
 is brownish, flecked with white, black, 
 and gray patches. There is a distinct spot 
 of white scales just back of the head, and 
 another on the exposed tip of the abdo- 
 men. The adults leave their hibernating 
 quarters in the spring and fly to the peas 
 coming into bloom. They are attracted to 
 the flowers, because they must feed on 
 pollen before they are able to lay eggs. 
 The tiny, long, yellow or orange-colored 
 eggs are laid on the developing pea pods. 
 The larvae or grubs upon hatching bore 
 directly through the egg shells and pod 
 and enter the developing peas. Except for 
 the first stage, the larvae are legless, grub- 
 like, white with a brown head. 
 
 The entrance made by the larvae into 
 the peas is very small and difficult to de- 
 tect. The larvae complete their develop- 
 ment inside the peas in from 30 to 50 
 days. After constructing a tunnel to the 
 seed coat so that the adults can more 
 readily emerge, the larvae pupate. After 
 10 to 15 days the pupae transform to the 
 adult beetles, which escape from the peas 
 by cutting out a circular hole in the seed 
 coat. There is only one generation a year 
 and, unlike the several species of bean 
 weevils, the pest does not breed in stor- 
 age or in dry peas. 
 
 ^ y£i 
 
 ^SL# 
 
 
 
 \ ^ ^ 
 
 These insects entered the peas as larvae and 
 now emerge as full-grown weevils. 
 
 [23] 
 
CONTROL: The pea weevil can be 
 controlled by thoroughly dusting the pea 
 vines with a dust containing 5 per cent 
 DDT. Not more than two applications 
 are necessary : the first should be applied 
 shortly after the start of bloom; and the 
 second at the height of the blooming pe- 
 riod. Where DDT is applied, do not feed 
 the treated pea vines to livestock. As a 
 sanitary measure, destroy the pea vines 
 as soon as harvest is completed. A dust 
 containing 0.75 per cent rotenone is also 
 effective. Apply the treatment at weekly 
 intervals from shortly after the begin- 
 ning until the end of the blooming period. 
 
 ROOT MAGGOTS 
 
 Root maggots include several species 
 that seriously attack the roots of grow- 
 ing plants. The maggots are the larvae 
 of flies; they are legless, without distinct 
 heads, and are nearly white. They bore 
 into the germinating seeds and roots, and 
 often make difficult the growing of cer- 
 tain vegetables. There are three impor- 
 tant species: (1) The cabbage maggot 
 attacks cabbage and related crops. It is 
 serious in summer. (2) The seed-corn 
 maggot attacks germinating seeds and 
 roots of corn, beans, peas, tomatoes, and 
 other crops. It is particularly serious 
 where the soil is moist and cold; and it 
 is usually most active early in the sea- 
 son. (3) The onion maggot attacks on- 
 ions, shallots, garlic, and related crops. 
 
 CONTROL: To control the cabbage 
 maggot, place disks of tarred paper 
 about the plants at the ground level and 
 in close contact with the soil at the time 
 of transplanting. The disks should be 
 about 3 inches in diameter, with a hole 
 in the center and a slit to facilitate plac- 
 ing them about the stem of the plants. 
 Dichloroethyl ether has proved effective. 
 It is available in commercial ready-mixed 
 preparations, which may be added to 
 water at the rate of 1 to 400, or 2 tea- 
 spoons to the gallon, and applied with 
 sprinkling can to the soil around the 
 
 plant at the rate of 1 cupful to a plant or 
 1 cupful to 8 inches of row. 
 
 To avoid injury from the seed-corn 
 maggot, particularly to beans and corn, 
 delay planting until the soil warms up. 
 To avoid injury from the onion maggot, 
 spray the soil about the plants with 2 
 parts of a highly refined oil emulsion to 
 100 parts of water. Destroy cull onions 
 as soon as harvest is complete. Most ef- 
 fective control of root maggots can be 
 obtained with chlordane preparations. 
 Soil application of chlordane, dieldrin, 
 or heptachlor before planting, or dusting 
 the transplants before setting out is also 
 helpful. Follow manufacturer's recom- 
 mendations. 
 
 The seed-corn maggot is best con- 
 trolled by using treated seed where this 
 is available. 
 
 SNAILS and SLUGS 
 
 (Not insects but have chewing habits.) 
 
 All gardeners know the domage done by 
 snails and slugs. They feed chiefly at night, and 
 frequently cut off young plants. Poison bait is 
 the best control. 
 
 [24] 
 
Snails and slugs are so well known to 
 nearly everyone that detailed descriptions 
 are not necessary. The former have shells, 
 the latter do not. Both have chewing 
 mouth parts and feed chiefly at night. 
 They attack many kinds of plants and 
 often leave slime tracks upon the plant 
 on which they have fed. 
 
 CONTROL: Snails and slugs are best 
 controlled with poison baits that contain 
 both calcium arsenate and metaldehyde. 
 Such baits are available as commercial 
 products and are obtainable from almost 
 any dealer selling insecticides. Best re- 
 sults are obtained by scattering the bait 
 in the evening on wet ground. Dusts 
 containing 10 per cent metaldehyde give 
 satisfactory control, as does dusting 
 plants with calcium arsenate. Do not 
 apply these poisons to edible parts of 
 plants unless the residue can be removed. 
 Many of the pests can be destroyed by 
 hand-picking. 
 
 SOD WEBWORMS or 
 LAWN MOTHS 
 
 The two lawn-infesting insects are the 
 fawn-colored lawn moth and the silver- 
 barred lawn moth. The adults are small. 
 The forewings of the fawn-colored lawn 
 moth are brown, variegated with buff, 
 white, and black; those of the silver- 
 barred lawn moth are golden with a long- 
 itudinal silver stripe. These pests breed 
 continuously throughout the late spring, 
 summer, and early fall. The adults fly 
 slowly over lawns at dusk while scatter- 
 ing eggs in the grass. All damage is done 
 by the caterpillars which hatch from the 
 eggs. The caterpillars when full-grown 
 are about % inch in length and are gray- 
 ish with black spots. 
 
 Serious damage is done to bent and 
 bhiegrass and other grass lawns during 
 the summer and early fall. The crowns 
 and new buds are attacked, which causes 
 irregular brown spots in the lawn. Dam- 
 age by these insects might be confused 
 with the lawn diseases causing brown 
 
 patch and dollarspot, but the insect dam- 
 age can be distinguished by unevenness 
 of grass height and irregularity in the 
 shape of dead spots. 
 
 Accurate determination of infestation 
 can be obtained by wetting the sod about 
 the dead areas with a pyrethrum solution. 
 Use a commercial pyrethrum prepara- 
 tion that contains 2 per cent pyrethrins, 
 diluted with water at the rate of 1 part 
 to 400 (2 teaspoons to the gallon), and 
 apply to the grass by means of a sprin- 
 kling can at the rate of 1 gallon to the 
 square yard. Any webworms present will 
 come wriggling to the lawn surface. A 
 serious infestation is indicated if at least 
 100 individuals per square yard come up 
 within 10 minutes. 
 
 From top to bottom, the adult and the larva 
 of the fawn-colored lawn moth; the adult of 
 the silver-barred lawn moth with the bar show- 
 ing conspicuously in this profile view; the larva 
 of the silver-barred species. 
 
 [25 
 
CONTROL: A number of insecticides 
 are effective in controlling sod web- 
 worms. Pyrethrum products and dichlo- 
 roethyl ether at proper dosages result in 
 a good kill of the caterpillars present, but 
 have no residual action, and the lawns are 
 subject to reinfestation right after treat- 
 ment. However, some residual action can 
 be obtained if dichloroethyl ether is used 
 in combination with lindane. If these 
 materials are used, follow the directions 
 given on the container. A spray contain- 
 ing 2 ounces, by weight, of actual DDT, 
 chlordane, or toxaphene, or 1 ounce by 
 weight of aldrin, dieldrin, or heptachlor 
 is very effective in controlling lawn 
 moths. The amount of insecticide sug- 
 gested, when diluted with enough water, 
 is sufficient to control the worms on 1,000 
 square feet of lawn. Another very satis- 
 factory treatment to prevent reinfestation, 
 is to spray the lawn with a standard lead 
 arsenate spray. The standard lead ar- 
 senate is used at the rate of 5 pounds 
 to 50 gallons of water. This amount is 
 enough to treat 1,000 square feet. The 
 mixture is best applied with a sprinkling 
 can, and the spray should be allowed 
 to dry before rewatering. Lead arsenate 
 is very poisonous and every effort should 
 be made to keep it off vegetation which 
 is intended for either human or animal 
 food. Granules which contain dieldrin 
 and lindane are effective if they are 
 evenly scattered over the lawn. In us- 
 ing any of the above treatments care- 
 fully follow the directions given on the 
 containers. In no instance should chil- 
 dren or pets be allowed on the lawns until 
 the insecticides have been watered into 
 the grass and the lawns given an op- 
 portunity to dry. 
 
 SOWBUGS and PILLBUGS 
 
 (Not insects but have chewing habits.) 
 
 ^Pi r '"9t 
 
 The dooryard sowbugs live in moist, damp 
 places. 
 
 Sowbugs and pillbugs are dark gray 
 or slate colored, with chewing mouth 
 parts. They are somewhat flattened, have 
 seven pairs of legs, and move rather 
 slowly. They breathe by means of gills 
 and therefore must live in moist, damp 
 places. Unless present in large numbers, 
 they are seldom destructive. They are, 
 however, particularly injurious to seed- 
 lings. Pillbugs can be distinguished from 
 sowbugs in that they curl up into a round 
 ball when disturbed. 
 
 CONTROL: Sowbugs and pillbugs can 
 be controlled by dusting the infected 
 ground with a calcium arsenate flour mix- 
 ture. Thoroughly mix 2% pounds of cal- 
 cium arsenate with 1 pound of white 
 flour. This quantity of the mixture, thinly 
 but evenly applied is sufficient to dust 
 700 square feet. This mixture is a poison 
 and should not be applied to portions of 
 
 STOMACH POISONS FOR CHEWING PESTS 
 
 [26] 
 
leafy or heading vegetables which are to 
 be eaten, nor to other vegetables after the 
 fruit is set. Poison baits recommended for 
 cutworms, snails, and slugs are partially 
 effective. Baits containing dieldrin are 
 most effective and granules containing 
 both dieldrin and lindane give satisfac- 
 tion. 
 
 A 5 per cent DDT dust applied to their 
 hiding places gives very effective control. 
 Avoid dusting shrubbery; DDT and 
 similar insecticides will kill beneficial in- 
 sects that help to control red spiders and 
 several other important pests. 
 
 TOMATO PINWORM 
 
 The tomato pinworm, the caterpillar of 
 a tiny moth, is about % inch long when 
 fully grown. The young worms are light 
 pink, but the older ones appear as grayish 
 purple. They attack all portions of the 
 vine, but are most destructive to the fruit. 
 They may enter it at any point, but 
 usually they enter at the stem end and 
 burrow into the core and the fleshy parts 
 that radiate from it. The pest also attacks 
 potato, eggplant, and nightshade. The 
 area where the pinworm is likely to be a 
 problem is limited to southern California 
 and the central and southern San Joaquin 
 Valley. 
 
 CONTROL: This pest is controlled by 
 a 5 per cent DDT dust or a cryolite dust 
 thoroughly applied to the vines. In sea- 
 sons when pinworms are serious, dust 
 the vines first when the fruits are about 
 the size of marbles. Apply two other dust- 
 ings at 2-week intervals, and a fourth 
 after harvest has started. Any dust on the 
 fruit should be carefully washed or wiped 
 away. If the tomato mite is also believed 
 to be present, use a dust containing 50 
 per cent sulfur. 
 
 VEGETABLE WEEVIL 
 
 The vegetable weevil is a brown or 
 buff-colored snout beetle measuring 
 about % inch in length. The larvae are 
 legless, light-green grubs that measure 
 about V2 inch long when full grown. Both 
 the adults and larvae feed on the foliage 
 of a number of winter and spring vege- 
 tables; the larvae also feed on vegetable 
 roots, particularly of carrots and turnips. 
 The vegetable weevil, which has spread to 
 many parts of California, is particularly 
 serious as a pest in the cooler coastal 
 areas. It has not been reported as being 
 a serious pest of flowering plants and 
 ornamentals. 
 
 CONTROL: As soon as the first larvae 
 are seen, the infested plants should be 
 treated thoroughly with a 5 per cent DDT 
 dust, or a dust containing malathion. Use 
 the same treatments for control of the 
 
 *, v ' yV ■■•■• 
 
 The fat grubs of the vegetable weevil destroy 
 root vegetables, such as turnips. 
 
 CONTACT INSECTICIDES FOR SUCKING PESTS 
 
 [27] 
 
adults. If a residue problem is involved, 
 use a 1 per cent rotenone dust. Poison 
 baits can be effectively used against the 
 adults but are not effective against the 
 larvae. 
 
 WIREWORMS 
 
 Wireworms, the immature stages of 
 "click beetles," have smooth, round 
 bodies and tough skin. They are shiny 
 and vary in color from pale yellow to 
 dark brown. They live in the soil, pre- 
 ferring lighter soil types. Most of the 
 destructive species are not more than 1 
 inch long. Usually one to three years are 
 necessary for wireworms to complete 
 their development. Wireworms injure 
 plants by cutting off roots, by boring into 
 tubers and fleshy roots, or by penetrating 
 into the root and up into the stems of 
 plants. They may also seriously attack 
 germinating seeds. 
 
 CONTROL: They can be attracted to 
 baits, such as carrots, which are placed 
 in the moist surface soil and spaced 2V2 
 to 3 feet apart each way. If the tops are 
 left on, the carrots can easily be pulled 
 out every few days, the wireworms re- 
 moved, and the baits put back into the 
 soil. Chlordane, heptachlor, dieldrin, or 
 aldrin applied and incorporated into the 
 soil are most effective in the control of 
 
 Wireworms live in the soil, and attack roots and 
 germinating seeds. 
 
 wireworms. The use of treated seed is 
 also very effective in protecting against 
 wireworm. Seed that has been treated by 
 the producer should be purchased where 
 available. 
 
 The fumigant dichloroethyl ether in 
 combination with lindane is highly effec- 
 tive against wireworms. 
 
 The fumigant ethylene dibromide also 
 is an effective control. This fumigant is 
 available in small containers for home 
 gardens. It should be applied prior to 
 planting. 
 
 In applying any of the above treat- 
 ments carefully follow the directions as 
 given on the container. 
 
 Sucking Pests 
 
 APHIDS 
 
 Aphids are small, fragile, soft-bodied 
 insects with sucking mouth parts. Some 
 have wings, others do not. They are 
 black, green, yellowish, or pinkish, and 
 their bodies are naked or perhaps cov- 
 ered with a powdery wax. They live in 
 colonies where they excrete quantities of 
 honeydew which attracts ants and on 
 which a sooty mold fungus grows. Many 
 species attack vegetables and other gar- 
 
 den plants, causing deformation and 
 curling of leaves. If not controlled, they 
 make the growing of certain plants very 
 difficult. 
 
 CONTROL: Aphids are controlled with 
 contact insecticides containing mala- 
 thion, lindane, nicotine, pyrethrum, ro- 
 tenone, organic thiocyanate, highly re- 
 fined mineral oil, or combinations of 
 these materials. Because many of the 
 aphids develop on the underside of leaves, 
 thoroughness of application is one of the 
 
 [28] 
 
The wingless species of aphids found in great 
 numbers on many plants. 
 
 most important factors in obtaining good 
 control. For satisfactory results, spray or 
 dust as soon as aphid colonies are ob- 
 served. If you wait until after leaves are 
 curled, control is difficult because the 
 aphids are hard to reach with the spray 
 or dust. Destroy infested plants as soon 
 as harvest of that crop is complete. 
 
 To prepare a nicotine spray use 1 tea- 
 spoon nicotine sulfate solution and 2 
 tablespoons soap to 1 gallon water. Dis- 
 solve the soap in a small quantity of 
 warm water before adding to mixture. 
 
 HARLEQUIN CABBAGE BUG 
 
 The harlequin cabbage bug is black, 
 with bright red and white markings on 
 its back. It is about % inch long when 
 mature. The immature forms are also 
 highly colored. Both the adults and the 
 
 Harlequin cabbage bugs must be killed, as they 
 do severe damage. 
 
 young injure plants by sucking the juice. 
 The insect is a serious pest of cabbage 
 and related plants. Feeding causes de- 
 formation, accompanied by whitish or 
 yellowish spotting of the leaves. In heavy 
 infestations the affected plants wilt, 
 wither, and die. 
 
 CONTROL: The harlequin cabbage 
 bug is very difficult to control. Every 
 effort should be made to keep it from be- 
 coming established. Wild radish and 
 mustard are breeding plants and should 
 therefore not be allowed to grow near a 
 garden. Old cabbage, cauliflower, broc- 
 coli, or other cruciferous plants should be 
 removed, since they furnish breeding and 
 hiding places. 
 
 Hand-pick and destroy any bugs ob- 
 served and also the egg clusters found 
 usually on the underside of the leaves. 
 A malathion spray or dust is partially 
 effective against the young, but not 
 against the adults. Malathion plus 5 per 
 cent DDT gives some relief but this can 
 be used only up to the time that the edible 
 portions of the plant begin to form. A 
 0.75 per cent rotenone dust, thoroughly 
 applied, is effective. A 10 per cent nico- 
 tine dust, or a strong nicotine and soap 
 spray is somewhat effective against the 
 nymphs. 
 
 LEAFHOPPERS 
 
 Leafhoppers are slender insects with 
 forewings thickened and often colored, 
 and with minute bristle-like antennae. A 
 number of species attack garden plants. 
 The adults are yellowish green to green- 
 ish and many species may have a definite 
 color pattern. They range from about Vs 
 to % inch in length. They are active 
 jumpers, and the young have a char- 
 acteristic habit of running sidewise. The 
 adults are capable of rapid flight. The 
 eggs are laid in the tender plant tissue. 
 The young are wingless, pale-colored, 
 and are generally found on the under 
 surface of the leaves. Injury is caused by 
 the insect piercing the plant and sucking 
 out the juices. First evidence of attack is 
 
 29 
 
Leafhoppers suck plant juices, and also carry 
 virus diseases to many garden plants. 
 
 a white stippling on the upper leaf sur- 
 face. In cases of severe attack this is fol- 
 lowed by drying up and death of 
 the attacked tissue. Besides direct injury, 
 leafhoppers are the carriers of a number 
 of very important plant virus diseases. 
 
 Among the garden crops that may be 
 seriously attacked are potato, squash, 
 beans, melons, rose, aster, and related 
 crops. 
 
 CONTROL: To destroy a sufficient 
 number of leafhoppers to prevent the 
 transmission of virus diseases in the gar- 
 den is not possible. Sprays or dusts con- 
 taining pyrethrum or malathion, if 
 thoroughly applied to all surfaces of the 
 foliage, are effective against those leaf- 
 hoppers that cause direct damage. A 5 
 per cent DDT dust or a DDT spray re- 
 sults in control, but may encourage an 
 increase in the red spider population. 
 Danger of red spider can be reduced if 
 sulfur is incorporated in the dust. A 
 DDT-sulfur mixture should be used with 
 caution as sulfur is likely to cause serious 
 injury to some kinds of melons and re- 
 
 lated plants. DDT in combination with 
 malathion also tends to suppress an in- 
 crease in spider mites and aphid popula- 
 tions. 
 
 MEALYBUGS (Aerial) 
 
 Mealybugs are among the most serious 
 sucking pests of plant life. They are from 
 Ys to 14 inch long, and have flattened, 
 elongate, oval bodies covered with a 
 white, powdery wax. This wax extends 
 from the margins in a series of filaments, 
 usually with two longer ones at the pos- 
 terior end. They usually develop in colo- 
 nies and are capable of slow crawling. 
 They excrete large amounts of honeydew 
 which not only attracts ants, but on 
 which a sooty mold fungus grows. Breed- 
 ing is most pronounced during the sum- 
 mer and fall, although the pest occurs on 
 the plants during the entire year. They 
 continuously injure house plants and 
 greenhouse plants of all kinds. 
 
 The eggs, which are usually oval, pale 
 yellow, or orange, are laid in cottony 
 masses which may cover large areas of 
 infested plants. Damage is done by the 
 females. The mature males have abortive 
 mouth parts and are tiny, white, two- 
 winged insects with two conspicuous long 
 
 Above is a typical species of aerial mealy- 
 bug with white, waxy body, growing in a 
 colony on a flower stalk. 
 
 [30] 
 
filaments at the tail end. During the mat- 
 ing season from near sunset to dusk on 
 warm, bright days the males may be pres- 
 ent in great swarms hovering in the air 
 about plants infested by the females. 
 
 CONTROL: Because of their waxy cov- 
 ering and because many of them may 
 feed upon the roots in the soil, mealybugs 
 are difficult to control. Summer oil emul- 
 sions, thoroughly applied to portions of 
 plants aboveground are effective. They 
 should be used at the rate of 1 to 1% 
 gallons to 100 gallons of water (3 to 5 
 tablespoons to the gallon). To insure 
 satisfactory results, the treatment should 
 be repeated two or three times at inter- 
 vals of one to three weeks. If other con- 
 tact sprays are used, such as malathion, 
 the directions on the containers should 
 be followed. Nicotine-soap sprays are of 
 little value unless used in combination 
 with oil sprays. Best results with most 
 contact insecticides are obtained when 
 they are used in combination with sum- 
 mer oil emulsions. 
 
 Many mealybugs and their eggs can be 
 removed by hosing them off with a strong 
 stream of water. If this treatment is re- 
 peated at intervals of every two to four 
 weeks, the pests can often be held in 
 check. 
 
 MEALYBUGS (Soil) 
 
 Ground mealybugs are very small; a 
 thin covering of white, powdery wax 
 makes their bodies almost white. They at- 
 tack the roots of numerous plants includ- 
 ing lawn grasses, practically all perennial 
 
 Soil mealybugs may be found in masses around 
 roots and are hard to control. 
 
 shrubs, and many annual plants. Where 
 an infestation is heavy, the soil about the 
 roots of plants will contain white cot- 
 tony masses. If these and the soil are 
 carefully examined, tiny, slow-crawling 
 mealybugs no larger than the head of a 
 pin can be seen. Injury to plants is caused 
 by the sucking out of plant juices, which 
 weakens the infested plants. 
 
 CONTROL: Soil mealybugs are very 
 difficult to control. Where plants are 
 growing, there is no highly satisfactory 
 control. 
 
 Where soil is known to be infested, 
 control can be obtained by spading it and 
 wetting it with dichloroethyl ether solu- 
 tion. A dichloroethyl ether emulsion 
 should be used at the rate of 3 teaspoons 
 to the gallon of water and applied to the 
 infested ground at the rate of 3% gal- 
 lons to the square yard. The application 
 should be made to moist soil, and should 
 not be applied where plants are growing 
 because the dichloroethyl ether is likely 
 to injure them. Treated soil should not 
 be planted for at least three weeks follow- 
 ing the application. 
 
 Some relief can be obtained by build- 
 ing a basin about the base of infested 
 plants and thoroughly wetting with a 
 nicotine-soap solution. Nicotine sulfate 
 should be used at the rate of 2 teaspoons 
 to the gallon of water. 
 
 This insect thrives in unmolested soils. 
 Cultivation is a very effective remedy 
 wherever it may be employed. Repeatedly 
 spading and turning the soil to dry it 
 out, or practicing summer fallowing will 
 rid the areas of the pest. 
 
 Mealybugs are readily brought into 
 gardens on potted plants. Many plants 
 tolerate soil mealybugs. Among these are 
 African marigolds, cabbage, camellia, 
 corn, dahlia, geranium, rose, stock, and 
 
 SCALES (Armored) 
 
 Armored scales, in general, are smaller 
 than unarmored scales. Depending upon 
 the species, they measure from about % 2 
 
 [31] 
 
A thick shell protects these armored scales 
 which suck out plant juices. 
 
 to % inch in diameter or length. They 
 are protected by a thick shell or scale 
 which covers the body, and range in color 
 from nearly white or light gray to dark 
 brown. The mature females may be oval, 
 nearly circular, elongate, or oyster shell 
 in shape. The male scales are much 
 smaller and often cannot be seen at all. 
 Most species are flattened, although some 
 are rather strongly convex. The scales 
 when newly hatched are active and move 
 about freely, but after the first molt they 
 lose their legs and become stationary. 
 
 These scales injure plants by sucking 
 the juice with their mouth parts, which 
 are adapted for this purpose. Some spe- 
 cies inject a toxic substance into the 
 plant, evidenced by a staining of the tis- 
 sue about the scale, or by a rapid death 
 of that part of the plant attacked. Unlike 
 the unarmored scales, little or no honey- 
 dew is secreted. The pests are found most 
 abundant on the stems and under surface 
 of the leaves, although they may also 
 occur on the fruit. There are from one to 
 many generations a year, depending upon 
 the species and the climatic conditions. 
 
 CONTROL: On deciduous plants ar- 
 mored scales can be controlled during 
 the full dormant season, December to 
 February, by thoroughly spraying with 
 a winter or dormant oil emulsion, or even 
 
 a summer oil emulsion, at the rate of 5 
 to 6 gallons to 100 gallons of water (16 
 to 20 tablespoons to the gallon). In the 
 growing season and on evergreen plants, 
 summer oil emulsion sprays applied dur- 
 ing the hatching period at the rate of 
 from 1 to 2 gallons per 100 gallons of 
 water (3 to 6 tablespoons to the gallon) 
 will control the pests. To insure satis- 
 factory results, the applications should 
 be repeated several times at 2- to 3-week 
 intervals. The effectiveness of oil sprays 
 can be improved by combining them with 
 malathion or rotenone. 
 
 Good control will be obtained if mala- 
 thion is used in combination with sum- 
 mer oil. For best results the directions 
 as given for the summer oil emulsion 
 should be followed. Frequent applica- 
 tions of nicotine sulfate and soap follow- 
 ing hatching give good control. When 
 contact sprays are used follow the direc- 
 tions given on the containers. A localized 
 infestation on a plant can sometimes be 
 removed by pruning. 
 
 SCALES (Unarmored) 
 
 Unarmored scales are small insects 
 with sucking mouth parts. The outer wall 
 of their bodies is thickened for protec- 
 tion. There are many economic species, 
 all varying greatly in shape. Some are 
 
 The soft scales attack woody plants in particu- 
 lar, and secrete quantities of honeydew. 
 
 [32] 
 
oval and somewhat flattened, others oval 
 and strongly convex, while others are 
 nearly globular when mature. They are 
 naked or partially covered with a pow- 
 dery, waxy secretion. A few have an elon- 
 gated, cottony egg sac. The young can 
 move about freely, but become more ses- 
 sile (or attached) with maturity. All 
 species are entirely stationary when fully 
 developed. Most species secrete large 
 quantities of honeydew which attracts 
 ants, and on which a sooty mold fungus 
 grows. A wide range of plants is attacked. 
 
 These scales are not a pest of vegetables 
 or most annuals. Woody plants are chiefly 
 attacked, and the scales are usually to be 
 found in greatest abundance on the stems, 
 branches, and under surface of the 
 leaves. Some species pass through two or 
 more generations in a year, with the 
 winter spent in the immature stage. 
 
 CONTROL: On deciduous plants, un- 
 armored scales can easily be controlled 
 in the dormant season by thoroughly 
 spraying with a winter dormant oil emul- 
 sion at the rate of 3 to 4 gallons to 100 
 gallons of water (8 to 12 tablespoons 
 to the gallon). During this period the 
 pest can also be controlled by spraying 
 with malathion and oil. Malathion, how- 
 ever, is not effective if applied in late 
 winter after the scales have started 
 rapid growth. No treatment of any 
 kind should be attempted from this 
 time on until the scales have completed 
 their development and the eggs have 
 hatched. During the growing season 
 and on evergreen plants, summer oil 
 emulsions may be used at the rate of 1 
 gallon to 100 gallons of water (3 table- 
 spoons to the gallon), or other contact 
 sprays such as malathion at the dosage 
 recommended by the manufacturer. To 
 insure satisfactory control in summer 
 apply treatment after the eggs have 
 hatched. If there is an uneven hatch a 
 second application may be desirable. In 
 a localized infestation some relief can be 
 obtained by pruning out the seriously 
 infested portion of the plant. 
 
 SPIDER MITES or RED SPIDERS 
 
 (Not insects but have sucking habits.) 
 
 Spider mites or red spiders are barely 
 visible to the naked eye. Their color 
 varies from very pale yellow to orange, 
 red, and greenish. Some species spin 
 much webbing and are usually abundant 
 on the undersides of leaves. They suck 
 the cell sap from the surface tissue of 
 plants. In severe infestations there is first 
 a fine white stippling, then a yellowing 
 of the infested parts, followed by com- 
 plete destruction of the tissue. They do 
 most damage during the warmest part 
 of the year. 
 
 CONTROL: The most effective mate- 
 rial for the control of spider mites is 
 Kelthane. Excellent control can also be 
 obtained with Aramite, but this material 
 cannot be applied to any product used 
 for human food. If either of these mate- 
 rials is used, carefully follow the direc- 
 tions given by the manufacturer on the 
 container. 
 
 In California in the warm interior val- 
 leys, spider mites can be suppressed by 
 thoroughly and evenly treating the in- 
 fested plants with dusting sulfur. In the 
 cooler coastal regions it may be necessary 
 to spray with a 1 per cent light summer 
 oil emulsion. The lower as well as the 
 
 Stippling of the leaves is typical red spider 
 damage. The tissue will then die. 
 
 [33] 
 
upper surfaces of the leaves must be 
 thoroughly wet with the spray to insure 
 satisfactory control. Infested plants 
 should be destroyed as soon as harvest 
 of that crop is complete. Indiscriminate 
 use of DDT, DDD, lindane, and diel- 
 drin has resulted in serious increases in 
 spider mite populations. The addition of 
 ■/4 to % DV volume of sulfur to the com- 
 mercial dust product will help control as 
 well as prevent a buildup of this pest. 
 Malathion sprays are effective in killing 
 spider mites, but are not effective against 
 the eggs, and so a second spray should 
 follow after the eggs hatch, in 7 to 10 
 days. 
 
 SQUASH BUG 
 
 The squash bug is hard to control, and both 
 adults and eggs should be destroyed. 
 
 Squash bugs are grayish-brown, some- 
 what speckled, sucking insects nearly % 
 inch long when mature. The visible mar- 
 gin of the abdomen as seen from above 
 is orange or alternately striped orange 
 and brown. The young at first are pale 
 green with pinkish legs and antennae. 
 Later, the forepart of the body is dark, 
 and the rest becomes a pale grayish 
 brown. The shining brown eggs are usu- 
 ally laid in clusters on leaves and stems. 
 Both the adult and the young suck the 
 juices of plants. In serious infestations 
 
 the plants wilt and die. These bugs are a 
 serious pest of cucumbers, melons, pump- 
 kins, squash, and related plants. 
 
 CONTROL: The squash bug, like the 
 harlequin cabbage bug. is difficult to con- 
 trol; every effort should be made to keep 
 it from becoming established. The adults 
 and eggs should be promptly hand-picked 
 and destroyed. Squash and other host 
 plants should be destroyed as soon as the 
 harvest of that crop is complete. Spraying 
 with a strong nicotine and soap spray (2 
 to 3 teaspoons of nicotine sulfate to a 
 gallon of water in which 2 or 3 table- 
 spoons of powdered soap have been dis- 
 solved), or dusting with a 4 per cent 
 nicotine dust (10 per cent nicotine sul- 
 fate) kills many of the very young, but 
 not the more mature and adult bugs. 
 Pyrethrum dusts containing at least 0.2 
 per cent pyrethrins are somewhat effec- 
 tive against the young bugs. A thorough 
 treatment with malathion is somewhat 
 effective against the small nymphs. 
 
 THRIPS 
 
 Thrips are small, slender insects, pale 
 to nearly black, with mouth parts con- 
 structed primarily for sucking. They are 
 about Y2-) inch long and usually have two 
 pairs of fringed wings, carried length- 
 wise over the back. Both the adults and 
 the nymphs, or immature forms, of most 
 species do damage. Their rasping and 
 puncturing of the surface plant cells 
 cause silvering of the leaves, fruit, and 
 stems. Thrips have a habit of feeding in 
 colonies. Attacked surfaces frequently be- 
 come deformed, dry. and may drop. 
 
 CONTROL: Malathion dust or sprays 
 are very effective against thrips, as are 
 DDT and toxaphene dusts and sprays or 
 mixtures that contain lindane or dieldrin. 
 
 STOMACH POISONS FOR CHEWING PESTS 
 
 [34] 
 
DDT, lindane, toxaphene, or dieldrin 
 should not be applied to portions of 
 plants intended for human consumption 
 unless the residue can be removed. When 
 these materials are used, carefully follow 
 the directions on the container. A nicotine 
 soap spray at the rate of 1 teaspoon of 
 nicotine sulfate solution and 2 table- 
 spoons of soap to 1 gallon of water can 
 be used. Thorough application is neces- 
 sary. The treatment should be repeated 
 every 10 days until the pest is held in 
 check. Destroy infested plants as soon 
 as harvest is complete. 
 
 TOMATO PSYLLID 
 
 The tomato psyllid is related to aphids. 
 It is approximately the same size as the 
 latter and the adults resemble miniature 
 cicadas. The eggs are very small, yellow, 
 and are attached to the leaves by means 
 of a short stalk. All damage is done by 
 the scale-like nymphs or immature forms, 
 which are yellowish orange to green in 
 color, and flat and elliptical in shape. The 
 nymphs are somewhat similar to those of 
 certain whiteflies, and are normally found 
 on the under surface of the leaves. They 
 have a row of wax glands. When abun- 
 dant, the white wax which is secreted may 
 be seen on the leaves and even on the 
 ground about the plants. Nournishment 
 is obtained by sucking up the cell sap. 
 
 Injury is caused by a toxic substance 
 which is injected into the plant. This 
 causes a stunting of the plant and a yel- 
 lowing and curling of the leaves; a con- 
 dition known as "psyllid yellows." 
 
 The tomato psyllid attacks a number of 
 different plants and is at times a serious 
 pest of tomato and potato. Damage by 
 the pest in California is localized and is 
 limited to the cooler coastal regions. 
 
 Nymphs of the tomato psyllid are shown with 
 white dots of excrement. 
 
 CONTROL: The tomato psyllid can be 
 controlled with either malathion, DDT, 
 or sulfur compounds. Treatment is ap- 
 plied at first evidence of infestation and 
 should be repeated at 2-week intervals 
 until the pest is thoroughly controlled. 
 Follow directions on the label if mala- 
 thion or DDT is used. Dusting sulfur 
 thoroughly applied gives good control. 
 If a spray is desired, use 1 heaping table- 
 spoon of wettable sulfur, or a heaping 
 tablespoon of dry lime-sulfur to a gallon 
 of water. In order to insure successful 
 control, the insecticides must be thor- 
 oughly applied, so that the pests on the 
 undersides of the leaves are contacted. 
 
 TOMATO RUSSET MITE 
 
 The tomato mite is free living and 
 microscopic. Under a magnifying glass 
 this extremely small mite appears pear- 
 shaped and whitish yellow. It crawls 
 about slowly on the surface of the stems 
 and leaves of the tomato plant, sucking 
 
 CONTACT INSECTICIDES FOR SUCKING PESTS 
 
 [35] 
 
The lower leaves of this tomato plant are dry- 
 ing and dropping after mite injury. 
 
 the juices. These parts of the plant later 
 appear oily brown or russeted. Starting 
 on the stems near the ground, the in- 
 festation works up the plants gradually, 
 causing the lower leaves to dry and drop. 
 In time the entire plant may be defoliated. 
 This mite is among the most destructive 
 tomato pests in California. 
 
 CONTROL: The tomato mite is con- 
 trolled by thoroughly and evenly treat- 
 ing the plants with dusting sulfur before 
 serious damage occurs. As a rule the 
 vines should be dusted between June 1 
 and July 15, and thereafter every 2 to 4 
 weeks. If the plant is also infested with 
 worms, a dust mixture of sulfur and 
 cryolite, or sulfur and calcium arsenate, 
 or sulfur and DDT, or sulfur and DDD 
 may be used. If any one of these dust 
 mixtures is applied during the harvest 
 period, the tomatoes must be washed or 
 thoroughly wiped or peeled before they 
 are eaten. Sulfur, because of its action 
 on metal cans and lids, has a harmful ef- 
 fect upon tomatoes that are canned; this 
 is why tomatoes must be free of it. 
 
 Do not grow tomatoes near petunias, 
 a favorite host of the mite. 
 
 WHITEFLIES 
 
 Whiteflies are sucking insects about 
 Y 16 inch long. The body and wings of 
 the adults are covered with a fine, whitish, 
 powdery wax, from which the name is 
 derived. Although the adults feed, it is 
 the scalelike nymphs, or immature forms, 
 which cause the damage. They suck the 
 cell sap from the plant tissue. In heavy 
 infestations the leaves turn yellow, finalh 
 die, and drop. The nymphs secrete quan- 
 tities of honeydew, which attracts ants, 
 and on which a sooty mold fungus grows. 
 
 Whiteflies infest many kinds of culti- 
 vated plants and often occur in abun- 
 dance on weeds, such as morning-glory. 
 The nymphs are found on the under sur- 
 face of the leaves. 
 
 CONTROL: Whiteflies are controlled 
 with contact insecticides. Malathion or 
 malathion and oil sprays are effective. 
 Oil-and-nicotine or oil-and-pyrethrum 
 sprays are also effective. All of these are 
 available as commercial preparations. 
 
 Another spray — nicotine and soap — is 
 effective. Since whiteflies occur mostly on 
 the undersides of leaves, this under sur- 
 face must be thoroughly wet with the 
 spray. At least two and possibly three ap- 
 plications at seven-day intervals are 
 necessary to control this pest once an in- 
 festation is established. Destroy infested 
 plants as soon as harvest is complete. 
 
 
 , - ; ,. V^ 
 
 , 
 
 ; 
 
 *• 
 
 
 ^v 
 
 
 ■ «■■■■■■'.-■,'.,■ ■; : --; : 
 
 : 
 
 
 The nymphs of the whitefly feed on the under- 
 side of leaves. 
 
 f36] 
 
ROOT-KNOT NEMATODE* 
 
 (Not an insect but has sucking habits.) 
 
 The root-knot nematode, sometimes 
 called "eelworm" or "garden nematode" 
 is a microscopic worm which invades the 
 roots of many garden plants and remains 
 there as a parasite. It causes the forma- 
 tion of galls on the roots of susceptible 
 plants. These galls interrupt the flow of 
 water so that heavily infected plants be- 
 come unthrifty, have poor color, wilt, and 
 sometimes die. These nematodes are 
 widely distributed throughout California 
 and are particularly destructive in the 
 warmer regions. 
 
 Root-knot nematodes are usually most 
 destructive in sandy soils. They may be 
 introduced into home gardens in infested 
 seed potatoes, or on the roots of infected 
 plants, or carried in with infested soil. 
 
 Plants vary in their susceptibility to 
 root-knot nematodes. Among the less-re- 
 sistant hosts are such plants as beans, 
 potatoes, tomatoes, melons, rose, snap- 
 dragon, and pansy. Such plants as corn, 
 onion, strawberry, gladiolus, nasturtium, 
 iris, lily, tulip, and narcissus are rela- 
 tively resistant to attack. 
 
 When nematode injury is suspected, it 
 can be determined by digging up the 
 roots and examining them for galls. On 
 most host plants the galls are conspicu- 
 ous and occasionally grow to a diameter 
 of an inch or more. Nematode galls must 
 be distinguished from the beneficial 
 nodules of the nitrogen-fixing bacteria 
 which occur on leguminous plants. The 
 latter are loosely attached to the sides of 
 the roots, while nematode galls involve 
 all root tissues and cannot be separated 
 from them. 
 
 CONTROL: Where serious infestations 
 of root-knot nematodes occur, resistant 
 varieties of plants can be used. Because 
 warm weather is necessary for the nema- 
 tode to be destructive, many susceptible 
 plants can be grown in the winter at a 
 time when the nematodes are least active. 
 
 Chemical control of root-knot nema- 
 todes in the home garden is possible. 
 These treatments have certain limitations 
 but if properly applied control can be 
 successful. The most effective chemicals 
 are soil fumigants containing dichloro- 
 propene, ethylene dibromide, dibromo- 
 chloropropane, chloropicrin, or sodium 
 H-methyl dithiocarbamate. Some of these 
 fumigants are packaged in containers for 
 use in the home garden. Where fumigants 
 are used, the infested soil should be in 
 good tilth before application, and must 
 be treated at least two weeks before the 
 ground is planted. These chemicals, with 
 the possible exception of dibromochloro- 
 propane, should never be applied closer 
 than within 30 inches of growing plants. 
 Where trees and shrubs are growing, 
 never treat within the drip area of such 
 plants. 
 
 The directions for the use of these fu- 
 migants are given on the container and 
 in instructions that can be obtained at 
 the time the fumigants are purchased. 
 For the best results, the dosage rates and 
 procedures recommended on the con< 
 tainer should be closely followed. 
 
 * The authors are indebted to Merlin W. 
 Allen, Professor of Plant Nematology and Plant 
 Nematologist in the Experiment Station, Berke- 
 ley, for assistance in the preparation of this 
 section. 
 
 Fumigants must be used with cau- 
 tion. They are toxic to humans and 
 animals. If spilled on the skin wash 
 thoroughly with soap and water. 
 Clothing that has become contami- 
 nated should be thoroughly cleaned 
 before being worn again. Avoid pro- 
 longed breathing of the fumes of 
 these nematocides. 
 
 [37] 
 
The Diseases 
 
 Ornamental and vegetable plants are 
 subject to many diseases. Remedies for 
 some of these are not known or are not 
 practical for the home gardener to use. 
 Frequently, symptoms of a disease be- 
 come apparent too late for anything to be 
 done on the crops concerned. However, 
 as will be shown, various measures can 
 be taken in the home garden to avoid or 
 reduce the damage caused by many of the 
 diseases that occur. The subject of dis- 
 eases of plants is vast, and because of 
 this, only a few of the more common 
 diseases are included in this discussion. 
 
 SOIL-BORNE DISEASES 
 
 Many of the disease problems con- 
 fronting the home gardener originate in 
 the soil. These may result from organ- 
 isms, such as fungi, that are natural in- 
 habitants or have been introduced and 
 become established there. Many of the 
 disorders may be the result of poor cul- 
 tural practices or the result of excesses 
 or deficiencies of one or more mineral 
 salts. 
 
 DAMPING-OFF DISEASES 
 
 Damping-off is a serious disease in 
 seed and plant beds and may be caused 
 by any one of several fungi. Two distinct 
 types, preemergence and postemergence 
 damping-off, are recognized. In pre- 
 emergence damping-off, which is most 
 serious in cold, wet soils, the sprouting 
 seeds rot before they break through the 
 surface of the soil. This results in bare 
 spaces in the rows where the plants 
 should be and is usually blamed on poor 
 seed. Postemergence damping-off results 
 in wilting or rotting of the seedlings after 
 
 they emerge and is more common in 
 warm, humid weather when the plants are 
 grown in crowded conditions. Infected 
 succulent plants wilt and topple over, 
 whereas infected woody plants wilt but 
 frequently remain upright. Root and 
 crown decay may then follow. 
 
 CONTROL: The best control for damp- 
 ing-off is to prevent its start. This may be 
 done by germinating seeds in pasteurized 
 soil or in an inert medium such as 
 sphagnum moss or vermiculite. Soil can 
 be pasteurized by heat or by chemicals. 
 Heat is the most effective means of treat- 
 ing soil-borne pathogens in limited 
 amounts of soil or in restricted areas. 
 Heat may be applied in the wet form of 
 steam or hot water, or in dry form as 
 electricity or hot air. An important factor 
 to remember is that soil should be uni- 
 formly heated to 160° to 180° F for at 
 least io hour. Soil pasteurized in this 
 way can be used for planting as soon as 
 it cools. 
 
 For pasteurizing larger amounts of 
 soil, or where heat is not practical, chemi- 
 cal treatments may be used. Three of the 
 commonest chemicals used are formalde- 
 hyde, methyl bromide, and chloropicrin 
 (tear gas). They all have certain disad- 
 vantages — they are irritating or harmful 
 to the person making the applications, the 
 soil must be aerated following treatment, 
 and they cannot be used around growing 
 plants. However, these materials give 
 very good control of the damping-off or- 
 ganisms. Information about the use of 
 chemicals to pasteurize soil can be ob- 
 tained from the University of California 
 Farm Advisor's office in your county. 
 
 Recently, several new chemical prod- 
 ucts have been released which are very 
 
 [38] 
 
good for controlling damping-off organ- 
 isms. One of these, known as Panogen, 
 when mixed 1 : 10,000 and sprinkled over 
 the soil just prior to seeding, protects the 
 developing seedlings. A second com- 
 pound. Anti-damp, is reported to give 
 good control when diluted 1:100 and 
 applied to the soil. Both compounds can 
 be watered into the soil right after seeds 
 are sown and since they are not injurious 
 to growing plants when used at the 
 recommended dilutions, the treatment 
 can be repeated if trouble should develop 
 as the young plants emerge. 
 
 Another means of controlling damp- 
 ing-off is by the use of seed protectant 
 fungicides. These chemicals, when ap- 
 plied to the seed, disinfect the soil im- 
 mediately around the seed and give tem- 
 porary protection while the plant is in a 
 very susceptible stage. Many good seed 
 protectants are on the market, among 
 which are Ceresan, Semesan, Cuprocide, 
 Arasan, Tersan, Fermate, Spergon, Phy- 
 gon, and Dow compounds 6, 9, and 10. 
 Most of these are very good. Some, how- 
 ever, are better for certain seeds than 
 others. These should be applied accord- 
 ing to the recommendations of the manu- 
 facturer. Certain of these chemicals can 
 be mixed with the soil to control damp- 
 ing-off. For instance, one teaspoon of 
 Arasan mixed in a flat of soil protects 
 certain seedlings from damping-off or- 
 ganisms. Small experiments with differ- 
 ent materials and different plants mav 
 give desirable results. Captan has also 
 given good control when mixed in the 
 soil. 
 
 WATER MOLD ROOT ROT 
 
 Water mold root rot is caused by some 
 of the fungi that are closely related to 
 several of the damping-off organisms, and 
 may cause serious damage under condi- 
 tions of excess soil moisture. This disease 
 is of frequent occurrence in heavy soil 
 with poor drainage. A number of plants 
 are attacked, the more common being 
 
 azaleas, rhododendrons, camellias, heath- 
 ers, and many of the ornamental conifers. 
 Young plants are usually attacked but it 
 is not uncommon to see older plants die 
 from this trouble. Infected plants show 
 an unthrifty appearance. This may be 
 followed by permanent wilting, leaf-drop, 
 and eventually death of the plant. The 
 portion of the main stem at and below the 
 soil line becomes brown; a cut into this 
 area reveals only dead bark and wood. 
 
 CONTROL: The control is a matter of 
 prevention, since a well-drained, aerated 
 soil will prevent development of the 
 disease. 
 
 ARMILLARIA ROOT ROT 
 
 The fungus causing Armillaria root rot 
 is widespread in California. The disease 
 is also known as oak root fungus disease, 
 shoestring root rot, mushroom or toad- 
 stool root rot, or oak root rot. The fungus 
 is known to attack at least 470 species of 
 plants. It usually attacks conifers, de- 
 ciduous trees and broadleaf evergreens, 
 but may also attack herbaceous plants. 
 All plants are not equally susceptible to 
 the fungus and some trees may be in- 
 fected with no apparent damage. 
 
 The external symptoms are not always 
 diagnostic. The infected plants may ap- 
 pear unthrifty and may either linger on 
 for a long time or die suddenly. The most 
 reliable sign of the disease is the pres- 
 ence of large white mycelial fans or 
 plaques found between the bark and wood 
 of the roots and crowns of the infected 
 plants (see page 40) . In advanced stages, 
 the wood becomes wet and soggy. At 
 certain times of the year the fungus mav 
 produce mushrooms at the crown of the 
 infected plants (see page 40) . This mush- 
 room gives the disease its name "mush- 
 room root rot" or "toadstool root rot." 
 
 CONTROL: Control of this disease is 
 very difficult. Soil fumigation is one 
 method that has proved effective in many 
 areas. The best chemical at present is 
 carbon bisulfide. It is injected 6 or 7 
 
 [39] 
 
Left. Large white mycelial fans or plaques between bark and wood of roots and crowns of 
 infected plants are the most reliable signs of Armillaria root rot. Right. Fruiting bodies or mush- 
 rooms of the oak root fungus arising from an infected plant. 
 
 inches deep into the soil at the rate of 
 2 ounces (59 ml) every 18 inches. The 
 starting point of each injection row is 
 staggered to provide better coverage. 
 Most of the roots of infected plants 
 should be removed before injecting the 
 chemical. The use of carbon bisulfide 
 presents several difficulties in the home 
 garden. The chemical kills all plants in 
 the treated area and since roots of in- 
 fected plants may extend for quite a dis- 
 tance in the soil, large areas of the garden 
 may be involved. Fumigation with the 
 chemical is more effective if the soil is 
 dry. This is difficult in a garden where 
 water is needed to keep some of the de- 
 sired plants alive. 
 
 Exposing the crowns of infected plants 
 may prolong their lives because the 
 fungus is not favored by dry conditions. 
 Improving drainage in the soil also helps 
 to control the disease, especially in those 
 plants which show some resistance to the 
 fungus. 
 
 The home gardener's best control is to 
 plant resistant species of trees and shrubs. 
 The University has a list of ornamental 
 plants, available on request, that have 
 been tested and found to have some re- 
 sistance to the disease. 
 
 VERTICILLIUM WILT 
 
 Verticillium wilt is another very wide- 
 spread disease in California. If the fungus 
 that causes this disease is once estab- 
 lished in soil favorable to its develop- 
 ment it will remain for long periods, and 
 any susceptible plants placed in the in- 
 fested soil may be subject to attack. 
 
 The disease can be recognized by the 
 yellowing of the lower leaves followed by 
 death of the marginal tissues and, even- 
 tually, death and sometimes defoliation 
 of the lower plant. Examination of a cut 
 section of the stem will usually reveal a 
 brown discoloration in the woody part. 
 
 The fungus has a wide host range; in 
 fact, a list of susceptible plants is too 
 long to give here. It is particularly bad 
 in tomatoes, potatoes, strawberries, and 
 various melons. Other plants that are 
 quite susceptible are chrysanthemum, 
 rose, China aster, marguerite, eggplant. 
 New Zealand spinach, dahlias, peonies, 
 snapdragon, Salpiglossis, strawflower, 
 maple, elm. and many trailing berries. 
 
 CONTROL: Control of this disease is 
 difficult but a number of methods should 
 prove helpful to the home gardener. If 
 potatoes or tomatoes are grown, they 
 
 [40] 
 
should not be followed with a susceptible 
 crop, but with one which is resistant, 
 such as beans, beets, spinach, corn, or 
 flowers such as petunias, pinks, marigold, 
 calendulas, sweet pea, delphinium, be- 
 gonias, or flowering bulbs. 
 
 Resistant varieties, where available, 
 should be grown. Some varieties of chrys- 
 anthemum are quite tolerant of the fun- 
 gus. Manetti rose, used as rootstock, is 
 very resistant, and some of the flowering 
 varieties of roses show more resistance 
 than do others. 
 
 Another good control method is fumi- 
 gation of the soil with chloropicrin. This 
 may be done with a hand applicator or 
 even a syringe and a hypodermic needle. 
 For best results, soil should be slightly 
 moist and fairly warm. About % tea- 
 spoon (3 milliliters) of the chemical is 
 injected 6 inches deep at 1-foot intervals. 
 The beginning of the rows is staggered 
 to give better coverage. As soon as the 
 chemical has been injected, the hole 
 should be tamped shut. When the injec- 
 tions are completed, a light sprinkling of 
 water over the surface of the soil to 
 moisten the surface layer is helpful. It is 
 necessary to wait about two weeks before 
 planting in an area treated in this way. 
 
 SALT DAMAGE 
 
 A disorder of many plants, the symp- 
 tons resembling somewhat those of Ver- 
 ticillium wilt, results from too high a salt 
 concentration in the soil and in the water. 
 The injury, which is quite common in 
 California, appears on the aerial portions 
 of the plant as a marginal burning of 
 the leaves (see opposite). Many plants 
 are affected but salt injury is especially 
 common on rhododendrons, azaleas, ca- 
 mellias, gardenias, and magnolias. An 
 occasional heavy watering to leach the 
 excess salt from the soil is the best con- 
 trol. If the plant is in a container, soak- 
 ing the container overnight in a tub of 
 water will help to leach the salts. Im- 
 proving drainage will also help to control 
 
 Salt damage on magnolia leaf. The injury 
 usually appears as a marginal burning of older 
 leaves. 
 
 the difficulty. If this problem is serious, 
 using organic fertilizers such as hoof and 
 horn, blood meal, fish emulsion, et cetera, 
 in place of inorganic fertilizers will help. 
 When using any fertilizer, follow direc- 
 tions on the container. 
 
 MINERAL DEFICIENCY 
 DISEASES 
 
 In addition to the diseases resulting 
 from mineral excesses, there are also dis- 
 eases resulting from mineral deficiencies. 
 Many of the conditions can be corrected 
 by the addition to the soil of the lacking 
 element. The lime concentration of the 
 soil in many areas of California makes 
 certain elements such as zinc, manganese, 
 and iron unavailable to the plant. Iron 
 deficiency is the commonest. The most 
 striking symptom of this disorder is a 
 yellowing or chlorosis of the younger 
 leaves (see page 42). The yellowing 
 begins at the outer margins and pro- 
 gresses inward, the veins being the last 
 to lose their green color. Ornamental 
 plants commonly affected are acacia, 
 abelia. magnolia, gardenia, hydrangea. 
 
 r 4i i 
 
Iron chlorosis of hydrangea. Leaves showing 
 advancing stages of this disorder, which begins 
 as a yellowing at the outer margins and 
 progresses inward, the veins being the last to 
 lose color. 
 
 azalea, rhododendron, and liquidambar. 
 Peach and pear are also affected. 
 
 CONTROL: The best control is to make 
 the soil more acid. This can be done by 
 adding sulfur, or by incorporating or- 
 ganic matter into the soil. Spraying the 
 foliage with iron sulfate will frequently 
 give control, but it is not permanent and 
 
 must be repeated. Another material that 
 has given very good results when sprayed 
 or applied to the soil on some plants is a 
 material sold under the trade name 
 Greenz-26. This material, which contains 
 iron, when mixed with water at the rate 
 of 4 ounces to 5 gallons may be sprayed 
 on the foliage to correct the deficiency. 
 Certain plants may not respond to a 
 foliage application of this material but 
 may show response when the material is 
 added to the irrigation water at the rate 
 of 8 ounces per 5 gallons. Iron seques- 
 trene is another material which can be 
 sprayed on the growing plants or added 
 to the soil. With this material, it is ex- 
 tremely important to carefully follow the 
 manufacturer's directions or plant injury 
 may result. 
 
 STEM, FOLIAGE, AND FLOWER 
 DISEASES (Powdery mildew) 
 
 The powdery mildews are the com- 
 monest and the most troublesome of the 
 foliage diseases in California. These dis- 
 eases are caused by several closely related 
 fungus forms that attack a large number 
 of host plants. They are especially serious 
 on roses, dahlias, tuberous begonias, 
 zinnias, calendulas, sweet peas, phlox, 
 
 Left. Powdery mildew of euonymus showing typical powdery growth of causal fungus. Right. 
 Sunburn of rhododendron. Three leaves show characteristic brown area through the center of 
 the leaves. Leaf on right shows the brown area after it has been invaded by secondary fungi. 
 
 [42] 
 
live oak, euonymus, flowering crabs, 
 peaches, apples, grapes, beans, and cu- 
 curbit species such as squash, canta- 
 loupes, cucumbers, et cetera. 
 
 The fungus grows entirely on the sur- 
 face of the leaves, obtaining its food by 
 sending minute pegs into the cells of the 
 leaf. The masses of white fungus body 
 and the spore-bearing branches which 
 appear on the surface of the leaf have re- 
 sulted in the name "powdery mildew." 
 Most fungi require free water before the 
 spores can germinate and cause infection, 
 but the powdery mildew spores are 
 unique in that they can germinate and 
 cause infection in the absence of free 
 moisture. For this reason, these diseases 
 are very serious, even during dry periods 
 and, also, because of this, are difficult to 
 control. 
 
 CONTROL: Two chemicals can be used 
 to control powdery mildews. Dusting sul- 
 fur is an old but still very effective means 
 of controlling these fungi. In addition, a 
 new material known as Karathane (also 
 available as Mildex) has been found to 
 give excellent control on many crops in- 
 cluding roses, begonias, chrysanthe- 
 mums, zinnias, and dahlias. Care must be 
 taken in using these materials, especially 
 
 . 
 
 Rust on snapdragon. The casual fungi pro- 
 duce small pustules which rupture and release 
 red, brown or yellow spores. These give the in- 
 fected leaves a rusty appearance. 
 
 during hot weather, since they can cause 
 considerable foliage damage if used on 
 plants sensitive to them. It is suggested 
 that the tolerance of a particular plant 
 be determined before using these chemi- 
 cals extensively. 
 
 SUNBURN 
 
 Some of the shade-loving plants, such 
 as rhododendron, camellia, and azalea, 
 occasionally will be burned by too much 
 sun. This injury appears as a large brown 
 area down the center of the leaves (see 
 page 42) . Not only is it unsightly, but it 
 allows the entrance of organisms that 
 would not be able to enter healthy tissue; 
 in turn, these organisms make the injury 
 more unsightly. 
 
 CONTROL: The control is to place 
 susceptible plants in desirable locations; 
 once they are established and doing well, 
 do not move them to sunnier locations. 
 
 RUST DISEASES 
 
 Diseases known as the rusts are quite 
 prevalent in many areas of California. 
 They are so named because on infected 
 surfaces the causal fungi produce small 
 pustules which rupture, releasing red, 
 brown, or yellow spores that give the 
 plant a rusty appearance (see opposite). 
 The most commonly affected garden 
 plants are rose, chrysanthemum, snap- 
 dragon, carnation, hollyhock, iris, and 
 heuchera. 
 
 Merion and Kentucky bluegrass are 
 also attacked by rust fungi. The disease 
 first appears as reddish brown and 
 orange patches that usually spread 
 rapidly until the entire lawn may be 
 affected. Growth of the grass is then much 
 reduced. 
 
 CONTROL: Control rust fungi by 
 spraying with zineb (commonly sold un- 
 der the trade names Parzate and Di- 
 thane Z-78). In addition, certain cultural 
 practices will help in the control of these 
 diseases. Raking up and burning leaves 
 from the infected plant help remove the 
 
 [43] 
 
overwintering stages of the fungi. With 
 roses, pruning back so that no foliage is 
 left on the plant helps to keep the disease 
 from carrying over from one season to 
 the next. Watering plants in the morning 
 or watering so that none is splashed on 
 the foliage helps to control some of the 
 rust diseases. 
 
 Control of the disease in Merion and 
 Kentucky bluegrasses is difficult. Acti- 
 dione, a new antibiotic, and actidione, 
 ferrated, are reported to give fair control 
 of stem rust when used as a foliage spray. 
 Actidione is sold in tablet form and the 
 spray is prepared by dissolving 1 tablet 
 (380 mg) in 1 gallon of water. A wetting 
 agent such as a kitchen detergent should 
 be added to insure good coverage. Keep- 
 ing the lawn well fertilized and mowed 
 high will help reduce the damage caused 
 by this disease. 
 
 TWIG DIEBACK OF ROSE 
 
 Twig dieback of rose is a common 
 disease caused by a fungus considered to 
 be a weak invader. It usually enters 
 through pruning wounds and kills the 
 stump above the bud, but may occasion- 
 ally invade beyond and kill the whole 
 branch. 
 
 CONTROL: The control is simple and 
 consists of pruning just above a bud so 
 that there is no stub or "dead end" wood. 
 
 ANTHRACNOSE OF SYCAMORE 
 
 This disease is very common in syca- 
 more trees in California. It is caused by 
 a fungus which attacks only the develop- 
 ing leaves and twigs causing the leaves to 
 turn brown and die (see page 45). De- 
 foliation usually results from these infec- 
 tions. 
 
 CONTROL: The best control measure 
 is to spray the trees with a protective 
 fungicide. Time of spray application is 
 important. Spraying with Vancide 51 or 
 zineb (sold as Dithane Z-78 or Parzate) 
 in two applications as a delayed dormant 
 and broken bud stage or as broken bud 
 
 and young leaf stage will give good con- 
 trol. It is also helpful to prune out in- 
 fected twigs and branches. 
 
 SCORCH OF MODESTO ASH 
 
 This disease is similar to sycamore 
 anthracnose but differs in that the leaves 
 of the ash tree are susceptible at all stages 
 of development. The fungus causing this 
 disease attacks the leaves during wet 
 weather, causing brown patches over 
 large areas and at the edges (see page 
 45). It may also cause some defoliation. 
 
 CONTROL: Control of the disease is 
 by protective fungicides. The same fun- 
 gicides used to control sycamore an- 
 thracnose will probably be effective 
 against scorch. Since the disease is spread 
 entirely by rainfall, a good coverage on 
 the young leaves during the rainy season 
 is important. 
 
 FIRE BLIGHT 
 
 Fire blight is a disease resulting from 
 a bacterial infection. The bacteria enter 
 the plant primarily through flowers but 
 also through natural openings or wounds. 
 The disease causes serious damage on 
 pears and apples. It may also affect such 
 ornamental plants as flowering crabs, 
 pyraeantha, and hawthorn. The disease is 
 recognized by a sudden wilting of in- 
 fected blossoms, which, after a short time, 
 turn brown (see page 45). Leaves and 
 twigs may also be killed. The dead leaves 
 cling to the twigs and the aifected 
 branches appear to have been scorched 
 by fire — hence the name "fire blight." 
 
 CONTROL: The disease can be con- 
 trolled by the application of fixed copper 
 (about 1 teaspoon per gallon of water) 
 as a spray during the blossoming period. 
 If the plants continue to bloom for some 
 time, two or three applications at 5-day 
 intervals may be necessary. About */2 
 teaspoon of Dreft or other kitchen deter- 
 gent added to the copper and water mix- 
 ture will insure better coverage by the 
 spray material. Pruning out infected 
 
 [44] 
 
/ 
 
 € 
 
 Sycamore anthracnose attacks only the de- 
 veloping leaves and twigs and causes much 
 leaf drop. The leaf tissues around the veins are 
 most frequently attacked. 
 
 Scorch of Modesto ash. The fungus causing 
 this disease attacks the new foliage during wet 
 weather, resulting in scattered, brown patches 
 of dead leaf tissue throughout the leaves. 
 
 wood and twigs 6 to 8 inches below the 
 diseased area should also be done to in- 
 sure good control. This removes the prin- 
 cipal source of inoculum. The pruning 
 shears should be sterilized between each 
 cut with a Lysol solution (1 part of Lysol 
 diluted with 9 parts of water). Pruning 
 alone may be all that is necessary for 
 
 Fire blight of pear may be recognized by a 
 sudden wilting of infected blossoms which, 
 after a short time, turn brown. 
 
 control if the affected plant is well iso- 
 lated from other susceptible plants. 
 
 PEACH LEAF CURL 
 
 This is a disease principally affecting 
 peach. It is caused by a fungus that sur- 
 vives unfavorable conditions as spores 
 lodged on the surface of the tree. When 
 
 Peach leaf curl causes the young developing 
 leaves to thicken and curl. The parts affected 
 may vary in color from buff to bright red. 
 
 [45] 
 
conditions are suitable in the spring, the 
 spores germinate and infect the young 
 developing leaves, causing them to 
 thicken and curl (see page 45). The af- 
 fected parts may vary in color from buff 
 to bright red. Infected leaves usually 
 wither and drop off. The infection may be 
 serious enough to cause much defoliation. 
 CONTROL: The disease can be easily 
 controlled by applying a spray before the 
 buds begin to swell in the spring. 
 Ferbam, or Ziram. or a fixed copper 
 fungicide have all proved to give ade- 
 quate protection for this disease. 
 
 IRIS LEAF SPOT 
 
 A disease common on iris in California 
 is one caused by a fungus and known as 
 leaf spot. The first evidence of the trouble 
 is the appearance on the leaves of small 
 brown spots surrounded by a water- 
 soaked margin. The spots enlarge until 
 
 Iris leaf spot. Infected areas appear as 
 round spots. These may enlarge, coalesce, and 
 sometimes cause premature death of the entire 
 leaf. 
 
 they coalesce. Parts of the infected leaves, 
 particularly toward the tip, die, and 
 sometimes the whole leaf may die pre- 
 maturely (see opposite). The centers of 
 the older spots become gray with a red- 
 dish-brown border. 
 
 CONTROL: The fungus overwinters in 
 the old leaves and the best method of re- 
 ducing this disease is to carefully remove 
 and burn all of the leaves in the autumn 
 months. Spraying with the fungicide Fer- 
 mate, applied when the leaves are de- 
 veloping, will help protect the leaves 
 against infection. The heavy, waxy coat- 
 ing on the leaves of iris makes it very 
 difficult to get good coverage with fungi- 
 cides and therefore the addition of a 
 spreader-sticker is necessary. 
 
 VIRUS DISEASES 
 
 Many of the diseases encountered in 
 the home garden are the result of virus in- 
 fections. Viruses are extremely small en- 
 tities that are spread in various ways. 
 They are transmitted, most commonly, by 
 certain insects. This is done when the in- 
 sect, after feeding on a diseased plant, 
 moves to a healthy plant and injects the 
 virus it carries into the plant during the 
 feeding process. Another means by which 
 viruses may be transmitted is by contact 
 between diseased and healthy plants, or 
 by implements contacting first a diseased 
 plant and then a healthy plant. Certain 
 viruses may be carried within the seed 
 but this method of transmission is not 
 common. Plants propagated by vegeta- 
 tive means form still another means of 
 spreading viruses. Cuttings, scions, tu- 
 bers, bulbs, et cetera taken from a virus- 
 diseased mother plant almost invariably 
 harbor the virus. 
 
 Symptoms expressed by virus-infected 
 plants are variable. Usually, infected 
 plants are stunted and appear unthrifty. 
 Commonly, the first evidence of the dis- 
 ease is seen on the leaves. It may appear 
 as a mottle which has given rise to the 
 term "mosaic disease" (see specimens 
 
 [46 
 
If "J&SXZ 
 
 Carina mosaic and rose mosaic. The first evidence of virus-infected plants may be a mottle or a 
 yellowing of tissues, which has given rise to the term "mosaic disease." 
 
 here), or may be a general yellowing of 
 the foliage that is frequently confused 
 with deficiency diseases. Many viruses 
 cause distortion of the leaves and stems. 
 Color "breaking" in many flowers is the 
 result of a virus infection. 
 
 CONTROL: Control of virus diseases 
 is difficult, and once a plant is infected 
 nothing can be done for that particular 
 plant. Removing and destroying infected 
 
 plants will serve to minimize the danger 
 of spread. Control of insect vectors, al- 
 though not very successful over large 
 areas, may be helpful in preventing 
 spread of the virus in the home garden. 
 Since virus diseases can become, and fre- 
 quently are, very serious in vegetatively 
 propagated plants, care should be taken 
 to select only those plants for propagation 
 that are free of virus. 
 
 In our publications it is sometimes convenient to use trade names of products or equipment rather 
 than scientific identifications. In so doing it is unavoidable in some cases that similar products 
 which are on the market under other trade names may not be cited. No endorsement of named 
 products is intended nor is criticism implied of similar products which are not mentioned. 
 
 Co-operarive Ext 
 co-operating. Di: 
 
 ision work in Agriculture and Home Economics, College of Agr 
 ibuted in furtherance of the Acts of Congress of May 8, and Jun 
 
 ulture. University of California, and United States Department of Agriculture 
 30, 1914. George B. Alcorn, Director, California Agricultural Extension Service. 
 
 40wi-6,'59(C6937)MH 
 
PURPOSES OF A UNIVERSITY. 
 
 ..to explore 
 see new visi 
 .find new riches 
 
 "I like to compare scientific research 
 to mountain climbing in an unexplored range. 
 Considerable preparation, training, and a strong 
 motivation are required to get up to the 
 upper altitudes even if no one particular stretch 
 of the way is particularly difficult. 
 But once there, it is relatively easy for one 
 to see vistas or even to stumble across 
 new riches that people of equivalent ability 
 who have stayed behind, have no 
 possibility to see or to find." 
 
 Glenn T. Seaborg 
 
 Chancellor at Berkeley 
 
 Nobel Laureate in Chemistry, 1951 
 
 (From his address at the Secondary Education Board Conference. San Francisco. April 5, J957)