UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA CIRCULAR 314 April, 1929 TERMITES AND TERMITE DAMAGE S. F. LIGHTi TERMITE WORK IN" WILLOW- FOREWORD Termites of various species are found throughout California; no district can safely consider itself free from their attack. Because of the insidious nature of the infestation, the extent and importance of the damage they cause has long been underestimated. The damage to houses has apparently been increasing in recent years. 1 Associate Professor of Zoology. 2 University of California — Experiment Station The Termite Investigations Committee 2 was formed less than a year ago as a cooperative effort between various industries concerned and the University of California. Among the contributors are the Board of State Harbor Commissioners and various railroad and steamship companies, oil companies, sugar refineries, telephone com- panies, power companies, lumber companies and associations, and wood-preserving and creosoting companies. The committee has as its ultimate aim the discovery of the most effective methods of prevention and control. This circular is a contribution from the committee, and is intended to present a brief description of the termites, their habits, and the damage they do. At the end of the circular will be found recommenda- tions which embody the best information available at present on prevention and control. All such suggestions must be taken as tenta- tive and subject to revision in the light of the information now being gathered. E. D. Merrill, Director, California Agricultural Experiment Station. WHAT ARE TERMITES? Termites are insects, often erroneously called 'white ants.' They attack buildings and implements, and cause much damage and con- cern. Like other insects, they have six legs, and their bodies are made up of segments which are arranged in three clearly marked regions, head, thorax, and abdomen (see fig. 10). The head bears a pair of antennae or feelers, a pair of jaws, together with other complicated mouth parts and, in some cases, a pair of compound eyes. The thorax bears the six legs and the wings when present. Termites have a horny 2 The personnel of the executive committee of the Termite Investigations Com- mittee is as follows: A. A. Brown, Consulting Engineer, C. A. Kofoid, Department of Zoology. Chairman. s> F Light> Department of Zoologv. W » ?" Kil * bride ' So , u 7 the ™ Pacific C. B. Lipman, College of Agriculture. Railway Company, Vice-Chairman. _ _ _/ ... ' .. s » A . 1A J. Walter Kelly, McCormick Lumber E - D ' Merrill > Colle % e of ^culture. Company, Secretary-Treasurer. C. W. Porter, College of Chemistry. R. C. Barton, Pacific Telephone and M. Randall, College of Chemistry. Telegraph Company. Col. J. W. Williams, Western Pacific W. H. Dore, Agricultural Experiment Railway. Station. Frank G. White, Board of State Har- E. O. Essig, College of Agriculture. bor Commissioners. Emanuel Fritz, College of Agricul- Q. e. Young, Pacific Gas and Elec- ture. trie Company. W. H. Hampton, Standard Oil of Dr. T. E. Snyder of the United States California. Department of Agriculture, Bureau A. C. Horner, National Lumber Manu- of Entomology, and Mr. E. M. Ehr- facturers Association. horn of Honolulu, T. H., are con- F. D. Kinnie, Atchison, Topeka & nected with the committee in an Santa Fe Railway. advisory capacity. Cir. 314] Termites and Termite Damage outer covering which is shed or moulted at various times during development to allow for increase in size and changes in structure. Not all species and castes of termites are white. The workers, nymphs, and soldiers of the subterranean termites are white, but the reproductives are jet black (fig. 16, a, b, c) . The soldiers of all Fig. 1. Living termites suggest maggots or worms to many. The three types common in the Pacific Coast region vary considerably in size as may be seen in the photographs (natural size) shown above: upper, dry-wood termites (Kcdotermes minor); center, subterranean ter- mites (Reticuliterm.es hesperus) ; lower, rotton-wood termites (Termopsis angusticollis) . University of California — Experiment Station EN?f\AN£E CA1NETD B?TWt£fj WEATHER CRECK Fig. 2. How dry-wood termites (Kalotermes minor) may attack the framework of a building. The wood-dwelling termites never enter the ground, and require no moisture except that found in sound wood. Fortunately, the rate of increase of such a colony is slow, owing to the small egg-laying power of the queen, and to the facts that there are no true workers and that the nymphs, which do the Avork, are continually reduced in number by changing into soldiers and reproductives. The usual points of entrance are indicated in the upper part of the sketch. After mating and the loss of wings, the royal pair takes advantage of cracks and crevices already existing, or digs through the unbroken surface of the wood in a place protected from the wind and sun's rays, to start a new colony. ClR - 314 1 Termites and Termite Damage 5 species of termites have rather dark-colored heads (fig. lOd) and their bodies are usually darker than those of the workers. The winged reproductive forms are variously colored. In the case of the commonest termites of the United States, they are, as stated above, quite black. Since termites are not ants (see page 11), and since not all species and castes are white, the term * white ant' should be eliminated; it leads to serious misconceptions as to identity, habits, and methods of control of the insects properly named termites. Please cooperate to put this name, termite, into general use ! Habits of Termites Termites are social insects (figs. 1, 4). Just as honey bees live in colonies, have a distinct social life, and have their work divided among a queen, drones, and workers, so do the termites live in colo- nies, have a social life, and divide their work among specialized castes. Fig. 3. The attacks of the dry-wood termites (Kalotermes) on the sapwood and heartwood of untreated poles present serious problems in various parts of the country (see fig.. 13). These attacks may extend to the cross-arms (see fig. 15n) and in some cases even the wooden insu- lator pins are reduced to hollow shells as seen above. The details of their life, such as food habits, nature and location of dwellings, relation of castes and method of colony formation, differ markedly, however, from that of the honey bees. Not only are termites social, living in colonies, but each colony lives entirely shut off from the outside world and from interconnec- tion with other colonies of termites, even of the same species. The dwelling of the colony consists of (1) intercommunicating cavities within wood (fig. 2) or (2) connecting passage-ways within both the ground and the wcod, often interconnected by dark, earth-like run- ways or tunnels constructed by the termites (figs. 4 and 5). Termites live thus in darkness, in narrow passageways, where the temperature, the moisture, and probably the oxygen pressure are to some extent under their control. This cryptobiotic habit is of the University of California — Experiment Station msyqpYiNQ n°°%m§ ATTACK INC, WEATHER B0AI\£S L CELL KITH SOLDIER G-J^rf&S jft ■ Fig. 4. How subterranean termites (Reticulitermes hesperus) may attack the woodwork of the foundation of a building. After the loss of wings and mating, a pair goes into the ground, where they excavate "a royal chamber. The queen lays eggs from which the nymphs hatch. The nymphs eventually become workers, soldiers, or reproductives. While the soldiers guard the passageways, nvmphs and workers tunnel to the surface of the ground and build covered runways over the founda- tion or pipes to the woodwork, which they eat. They enlarge the excavations and provide the king, queen, and soldiers with food in the form of partially masticated wood. In the fall the workers and nymphs construct a tunnel to the surface from which the alates ) (winged reproductives) swarm, usually after the first heavy rain. This is the 'fall flight,' or swarm. A smaller flight occurs in the spring. Cir. 314] Termites and Termite Damage Fig. 5. Subterranean termites build covered passageways made up of. particles of earth and fragments of chewed wood over concrete or other impenetrable materials. In this way they preserve the continuity of their enclosed dwelling from the earth to the wood on which they feed. The covered ways shown above ran up over the concrete walls for two stories in a heated warehouse in the upper San Francisco Bay region. Such work is more common in the southern area and is common in central and northern California only in furnace rooms or other especially warm locations. 8 University of California — Experiment Station utmost importance in any consideration of the termites. To its influ- ence through the ages are due most of the characters of the workers and soldiers, their lack of eyes, of wings, of dark color, and of thick body covering (fig. la). Because of this habit, the control of termites by poison baits, the attack of other animals, or communicable diseases, or any of the other ordinary methods used in insect control, becomes difficult, if not impossible. Any such treatment would mean the handling of each colony individually, and since the colonies are enclosed and seldom give visible indications of their presence, this would not be feasible, particularly since there is no external indication to tell whether one or many colonies are involved. Termites have developed a system of division of labor. Each colony consists of various kinds of individuals especially fitted in form and by instinct to carry on diverse activities. These different kinds of individuals are known as castes. There are usually three castes: reproductives, workers, and soldiers (fig. 16). Certain termites have no specially developed workers, but the grub-like young indi- viduals of the other castes, known as nymphs (fig. lc, light-colored individuals), do the work of the colony. The Reproductive Caste The reproductives (figs 6, 10a, 12a, and 16 a, b, c) are male and female termites which are much more like ordinary insects than are the other castes. They have until after swarming, large, black, compound eyes; somewhat flattened bodies; and a thick, often dark- colored, body covering. They emerge as winged forms (alates) from older colonies at a more or less definite time each year (fig. 6). These flying termites are often mistakenly called 'flying ants.' They mate, drop their wings, and each pair starts a new colony, of which they are the permanent wingless king (fig. 16c) and queen (fig. 16o). In most termite colonies, the body of the queen becomes enlarged owing to the great development of the ovaries, thus allowing for more rapid egg-laying (fig. 4). The Worker Caste The workers (figs, la, 16#) are by far the most numerous mem- bers of a subterranean termite colony, and the ones commonly encoun- tered. They are the palest, usually the smallest, and the weakest in appearance of the adults found in a colony. They are wingless, blind, and usually entirely eyeless, with pale, rounded heads, inconspicuous jaws, and thin body covering. Nevertheless, this is the form which Cm. 314] Termites and Termite Damage does all the work of the colony, such as gathering food, taking care of and feeding the young, the king and queen, and the soldiers, and building such structures as the tunnels, mounds, nests, and fungus gardens, which the various termite species make. It is the workers, together with the immature individuals called nymphs, that make our termite problem. Fig. 6. Winged males and females swarm from the termite colony at certain times during the year. These mate, break off their wings, and start new colonies. The swarming of the subterranean termites of the genus Reticulitermes occurs in the middle of the day between 9 and 3 o'clock on the first clear day after the first real rain of the autumn; lesser swarms emerge under similar conditions in the spring. These male and female subterranean termites are jet black with gray wings and are commonly mistaken for 'flying ants.' The photograph above shows such a swarming from between the bricks in front of Stephens Union, University of California. They are shown about one-fourth natural size. Wood-dwelling termites have no workers, and these functions are accomplished by the immature stages or nymphs of the soldier and reproductive castes (figs. 10c and 12d). Since these are continually changing over into the other castes, the colonies of this type of ter- mite are constantly being depleted by the production of alates and their recurrent swarmings. Their colonies are relatively much smaller 10 University of California — Experiment Station for this reason, and also because of the slight egg-laying powers of the queen. Where a worker caste is present, as in the subterranean termites, the continually increasing number of workers results in the formation of colonies consisting of thousands of individuals. a b Fig. 7. The commonest and the palest and Aveakest type found in a colony of subterranean termites is the worker (a). In spite of their appearance of weakness these workers, as the name suggests, do the work of the colony, and all termite destruction is due to their activities. Wood-dwelling termites have no workers and the work of their colonies is accomplished by young stages of individuals which will become soldiers or reproductives (see fig. 10 b, c) . The soldier (b) of this species, Reticulitermes hesperus, the western subterranean termite, is also white-bodied but has a pale yellow head. By means of its heavy mandibles and lai'ge head it defends the colony against attack. The Soldier Caste Wingless, blind, practically eyeless, and sterile, the strange mem- bers of the termite community known as soldiers (figs. lb, lOd, 12b and c) attract the eye by reason of their greatly enlarged, colored, usually elongated heads, which are extremely thick and hard, and are armed with greatly enlarged, elongated, and often grotesquely toothed jaws (fig. lOd), which are used as weapons of defense. CiR. 314] Termites and Termite Damage 11 These soldiers, like those of man, seem to function chiefly, if not entirely, in cases of emergency, as when the colony burrows are opened by some chance, and the inhabitants exposed to the attack of their arch enemies, the true ants. Their relatively enormous, hard heads serve to block up passageways, while their mandibles or jaws serve to destroy individual enemies. Protected thus from flank attack, they are extremely effective. When outflanked, however, their clumsy movements and unprotected bodies and legs make them easy prey for true ants but a small fraction their size. Fig. 8. The subterranean termites take their cellulose where they find it and frequently destroy books and records in the process. Their workings are usually marked by deposits of earth and partly digested cellulose as seen in the case of the book photographed, which was attacked on the shelves of a bookstore in southern California. ANTS ARE OFTEN CONFUSED WITH TERMITES The small size and social habits of termites have caused them to be associated with ants in the public mind. In structure, the true ants are very different from termites; the ants may always be dis- tinguished by the possession of a narrow waist, while the termite is large-waisted. In life history, the termites differ in lacking the larval and pupal stages of the ant. A young termite is much like an adult, save in size (fig. 16i) . In habits also, the true ants and termites differ radically. Ter- mites live shut off from the rest of the world, feeding upon wood, while ants run about in the open and feed upon various materials, being especially attracted by sweets. These great differences in the habits of the two forms mean that they present utterly different economic problems, and are to be con- trolled by entirely diverse methods. Termites certainly are not ants, and control measures that are effective with true ants fail utterly in combating termites. 12 University of California — Experiment Station The work of certain other wood-infesting insects is frequently mis- taken for that of termites. Professor E. C. Van Dyke of the Depart- ment of Entomology and Parasitology has kindly made the following brief statement with regard to such insects: Fig. 9. Termites shun the light and live entirely shut off from the outside world. In their search for wood to eat, the subterranean termites build their dwellings in front of them in the form of tiny tubes or covered runways made of thousands of particles of earth or wood cemented together by secretions of the termite; each tiny particle is brought separately and put in place by a worker termite. Only the subterranean termites build these structures; the wood-dwelling termites are confined to the cavities which they excavate within the wood. Heat is favorable to such activities and such towers are frequently found in furnace rooms or running up to furnace pipes, as in the photograph, and from there up to the floor above. Note the pieces of waste wood on the ground ; these furnish breeding grounds for the termites. Cir. 314] Termites and Termite Damage 13 OTHER INSECTS COMMONLY CONFUSED WITH TERMITES 1. The true ants, particularly the carpenter ants of the genus Camponotus. The adults are quite different from termites, being fully pigmented and wasp-waisted and the larvae grub-like. The bur- rowings which are made in dry wood are much like those produced by Kalotermes, but the passageways are always clean, never partly clogged with excretory pellets. 2. The 'powder-post' and 'death-watch' beetles. The adults of these are small and linear or cylindrical and their larvae grub-like. They live generation after generation in old, well-seasoned timbers, honeycombing the wood and reducing it to a condition of powder which plugs the old burrows or is expelled from time to time through various shot-hole openings. The very small passageways, the numerous, small external openings and the powdery remnant in their workings help to differentiate them from termite workings. 3. Certain of the larvae of the true wood-boring beetles of the families Cerambycidae and Buprestidae. The work of these, though sometimes very evident and destructive, can always be told by the fact that the burrows are always plugged with fibrous frass or a sawdust-like material, unlike that of the termites, which is either earthy or composed of pellets. The larvae also are elongate and wormlike. HABIT GROUPS AND DISTRIBUTION OF PACIFIC COAST TERMITES Termites are world wide in distribution within the limits of the tropical, subtropical, and temperate zones. More than a thousand species are known. Of these, some forty-six are known to live in the United States, and there are but five states, those located in the north central region, from which termites have not been reported as yet. Of these forty-six species of termites, eleven, belonging to six different genera, are now known to occur in the Pacific Coast states, all of them being found in California and two new species await description. Although there are thirteen kinds or species of termites in the Pacific Coast region, but three of these species are of widespread eco- nomic importance. The thirteen species fall into three distinct groups, characterized by different life habits. Each of these groups is repre- sented by one of the three economically important species. These groups have been given names which it is hoped may come into popu- lar use since they define the economic problems involved. 14 University of California — Experiment Station Fig. 10. Rotten-wood termites, Termopsis angusticollis (five times natural size). The reproductive forms, which are winged for a time (a), swarm from the colony and pair. Both male and female of a pair now lose their wings and set about founding a new colony. The Cm. 314] Termites and Termite Damage 15 Rotten-Wood Termites The rotten-wcod termites belong- to the genus Termopsis, and are represented by the widespread species, Termopsis angiisticollis (fig. 10). These, our largest termites (see fig. lc for natural size), are common in logs and decaying wood in or on the ground along the Pacific Coast from British Columbia into Lower California, They do Fig. 11. Termites prefer the soft wood grown in the spring and generally leave the hard resin-filled summer wood, as shown in the photograph of a softwood pole attacked by the rotten-wood termites (Termopsis) in Oregon. Rotten-wood termites in middle and southern California usually start their attacks in decaying wood and go to sound wood when the supply of rotten wood fails, but reports from Oregon and Washington indicate some attacks on sound Avood in regions of greater moisture. not enter the ground, and while sometimes found working into sound wood, are dependent upon a constant moisture supply. There are two species, the large or common rotten-wood termite, Termopsis angusticollis (figs, lc, 10) and the small or dark rotten-wood ter- mite, Termopsis nevadensis. The latter ranges into Nevada and Montana. The alates of the two species are distinct, but more study is required to enable us to distinguish the soldiers and nymphs of these species. immature forms are known as nymphs (b, c) . Those destined to change into reproductives have wing-pads in later stages (&), those which will become soldiers (c) are darker and larger-headed. Nymphs do all the work of the colony; there are no true workers in the colonies of wood-dwelling termites. The soldier (d) is the defender of the colony, as might be sur- mised from the large head and mandibles. 16 University of California — Experiment Station In moist regions, such as the Pacific Coast from Central California to British Columbia, the rotten-wood termites are responsible for considerable damage to wood in or on the ground (figs. 11, 18). Fig. 12. Dry- wood termites never enter the ground and need no moisture supply. The colony consists largely of whitish, grub-like immature forms (d) known as nymphs, which will give rise later either to soldiers (b, c) or winged males and females, (a). The photo- graphs show the different castes of the common dry-wood termites, Kalotermes minor, enlarged five times. Dry-Wood Termites The dry-wood termites belong to the genera Kalotermes and Neo- termes, and are represented by the common dry-wood termite, Kalo- termes minor (figs, la, 12). These live, as the name would indicate, in dry sound wood, of trees, poles (figs. 13, 15), posts, timbers of derricks, and of buildings (figs. 2 and 13-15), from at least as far north as central Mendocino County south and southeast into Arizona and Mexico. They never enter the ground and require no special moisture supply. There are three species in California. Of these, the common dry- wood termite, Kalotermes minor (fig. 12), is by far the most common, widespread, and economically important. The southern dry-wood termite, K. huooardi is common and of economic importance in Ari- zona but is known only from the extreme southern and southeastern borders of California. The desert dry-wood termite, Neotermes simplicicornis, has a life habit different from the other two ; it is con- fined to the desert area (in California) and is found chiefly at or below ground level, and thus often in damper wood than Kalotermes. Cm. 314] Termites and Termite Damage 17 It is commonly found in mesquite and another desert plant, the Cali- fornia dalea (Parosela calif ornica) . In the Colorado desert and in Arizona it is of considerable economic importance. Fig. 13. Dry-wood termites are especially addicted to sapwood but often go from the sapwood into the heartwood, as seen in the photograph of a portion near the top of a second- growth, 'sucker,' pole. The soldiers of these three species may be readily distinguished by means of their antennae or feelers. Those of Kalotermes hubbardi have an enormously enlarged third segment, those of K. minor (fig. 12b) have the third segment less strikingly enlarged, while in Neo- termes simplicicornis there is a slight enlargement or none at all. 18 University of California — Experiment Station Subterranean Termites The subterranean termites belong to the genera Reticulitermes, Leucotermes, and Amitermes. They are represented by the western subterranean termite Reticulitermes hesperus (figs, lb, 6b, 7, 16), whose range extends along the whole Pacific Coast and back to the desert slopes and high mountains. • Fig. 14. The wood of houses is sometimes attacked by the dry-wood termites. As seen in the photograph above of the work of the common dry-wood termite {Kalotermes minor) they eat up to the paint itself, leaving cavities which yield at once to pressure. This specimen is from Suisun in the upper San Francisco Bay region, where such work is uncommon. The dry-wood termites are most numerous in the southwestern region of the United States and along the Pacific Coast into northern California. Fig. 15. Dry-wood termites usually make large irregular chambers, not conforming to the annual rings of the wood. Above (a) is a photograph of the work of the common dry-wood termite {Kalotermes minor) in the cross arm of a telephone pole. The colonizing pair of dry-wood termites drill a neat hole (b), which they soon plug up with chewed-up wood. Lumber in the pile should be protected during the swarming season. If spaces are left between pieces of lumber in the pile to admit light, termite invasion seems to be discouraged. Coverings also may be helpful. The subterranean termites live partly or almost entirely within the ground and always maintain a ground connection. They attack sound or decaying wood in or on the ground or build covered run- ways (figs. 5, 9, 20) over impenetrable foundations to reach wood above the ground. Species of the subterranean habit of life belonging chiefly to the genus Reticulitermes account for very material damage throughout practically all of the United States. CiR. 314] Termites and Termite Damage 19 There are three species of subterranean termites of economic impor- tance in the Pacific Coast region. A second species of Reticulitermes, R. tibialis, which we have designated the high-desert subterranean termite, replaces R. hesperus along the western desert slope of the Mojave and Colorado deserts, in certain parts of the San Joaquin Valley, and at some unknown level in the eastern mountains. The \s \ t Fig. 16. The western subterranean termite, Reticulitermes hesperus, shown above, five times natural size, is the most widespread and destructive species of the Pacific Coast. The winged reproductives, males and females, have jet black bodies and gray wings and swarm on clear days after rains in early autumn and spring. They drop to the ground, assort in pairs, lose their wings, and each successful pair founds a new colony. They are now known as king (c) and queen, (b) . The soldiers (d), workers (e) , and nymphs (/, g, i) are white and have given rise to the misnomer 'white ants.' Those nymphs which will give rise to winged reproductives show wing-pads (/) in later stages. The eggs (h) are bean-shaped, and the newly-hatched nymph (i) not greatly different from the worker save in size. short, broad, yellow head of the soldier distinguishes this species from R. hesperus, whose soldier has a long, narrow, pale head (figs, lb, 16d). R. tibialis is commonly encountered in the creosote bush or grease- wood (Larrea tridentata) and in other desert plants, while R. hesperus has not been found in such situations. In the low-desert areas in the Colorado Desert and the Imperial Valley no species of Reticulitermes is found. Here Leucotermes aureus occurs, which we have designated the low-desert subterranean ter- mite. Its habits and economic possibilities have been little studied, but it is known to have done considerable damage to woodwork in 20 University of California — Experiment Station Phoenix and elsewhere. It belongs to a genus known to be very de- structive in the American tropics. Long, slender mandibles charac- terize the soldier of Leucotermes, and the golden color of the alate is in strong contrast to the black of the alates of Reticulitermes. Fig. 17. The subterranean termites attack wood from the ground. Their workings are usually marked by deposits of earthy material or earthen-like deposits of wood waste. Their liquid feces deposited as oval yellow spots on the walls of their workings help to distinguish them from those of the wood-dwelling termites, whose feces are in the form of tiny pellets (see fig. 19). The photograph above of a telephone pole in Berkeley gives some idea of the appearance of their workings. In Arizona, Leucotermes is widespread, having as its natural reservoir, the giant cactus and the cholla. Reticulitermes tibialis occurs in the northern part of that state and R. humilis, a species related to R. hesperus, is common in much of the southern area. The five species of Amitermes are found chiefly in the desert regions and do very little damage. Cib. 314] Termites and Termite Damage 21 INDICATIONS OF TERMITE PRESENCE OR ATTACK General Signs Termites live a concealed life, and give external indications of their presence and activities in only four important ways: (1) by the failure of wood due to their attacks (fig. 14), (2) by the emergence Fig. 18. The work of termites in wood is often associated with a type of deterioration due to fungus attack properly known as dry rot. Indications point to the probability that the termites spread the fungus and give rise to conditions favorable to its growth. In the public mind termite damage is very commonly confused with dry rot. The piling in the photograph has been damaged by the rotten-wood termite (Termopsis), as is indicated by the accumulations of large pellets. It was one of a number of timbers thus damaged in an Oakland shipway. of the reproductive caste as swarming alates (fig. 6), (3) by the characteristic fecal pellets of the wood-dwelling termites dropped from their workings (fig. 19), or (4) by the characteristic covered runways (figs. 5, 20), 'towers (fig. 9), or tubes (fig. 21), built by sub- terranean termites from earth to wood or from wood to earth. 22 University of California — Experiment Station 'Dry Rot' Sagging floors and walls and the consequent difficulties with doors and windows are the most commonly noted results of wood failure in buildings. Much of wood failure is commonly attributed to dry rot. A great deal of this failure is actually due to the attacks of ter- mites of various types and a great deal of the actual dry-rot damage is due to the introduction and spread by the termites of the fungus and the moisture necessary to its development. Pf|^^!# Fig. 19. The workings of the wood-dwelling termites are characterized by accumulations of the tiny impressed fecal pellets shown in the above photographs twice natural size. The pellets of the rotten- wood termites (a) are much larger than those of the dry- wood termites (b) ; the latter are more perfectly formed. Signs of the Wood-dwelling Termites The frontispiece shows an extreme case of the work of the dry- wood termite. Their work can usually be detected by weak points in the wood where the galleries come close to the surface (fig. 14). The fecal pellets (fig. 19) present in the wood or near it, indicate that it is the rotten-wood or the dry-wood termite rather than the subter- ranean termite, since the latter does not produce pellets. The pellets of the rotten-wood termite are larger and less perfectly formed than those of the dry-wood termites (fig. 19). Cir. 314] Termites and Termite Damage 23 Signs of the Subterranean Termites Aside from a general failure of the wood, the work of subterranean termites is indicated in many cases either by a frayed-out condition of the wood at ground level (fig. 17) or, especially in the southern part of the state, by the characteristic earthen-like covered ways and tubes (figs. 20, 21). Fig. 20. Tubes and covered ways projecting the conditions of the colony home in the earth to their workings in wood are characteristic features of the activities of all subterranean termites. These are composed of tiny particles (b) of earth or partly digested wood. The common subterranean termite, Reticulitermes hespervs, builds these very extensively in southern California but rarely does so in the central and northern portions of its range. That it can do so is indicated by the photograph (a), which shows the runways built in a single night in the Termite Committee's laboratory in Berkeley by termites removed from ground connections. Investigation of Suspected Wood Open suspected wood and search for termites, for galleries eaten out by them, and for pellets. Collect termite specimens, particularly soldiers, from the infested wood, preserve in alcohol or other preserv- ing fluid and send to the biological headquarters of the Termite Investigations Committee, 216 Zoology Building, University of Cali- fornia, Berkeley. If no specimens are found, send in pellets or a sample of damaged wood. Use the form found on last page of this circular. 24 University of California — Experiment Station Fig. 21. Subterranean termites working in wood far from a ground contact at times build exploratory hanging tubes evidently in search of more immediate ground contacts and moisture sources. Those in the photograph, built in the basement of a house in southern California, were over three feet in length. HOW CAN TERMITES BE CONTROLLED? Methods to be employed will necessarily depend npon various factors, such as (1) the kind of termites actually involved, (2) the kinds common in the locality, (3) the frequency of occurrence of termites in the locality, and (4) the degree of damage to be expected in case of attack. These will naturally vary in different localities. Certain general suggestions may be made at this time to be used with intelligent modification in the individual instance. These are Cir. 314] Termites and Termite Damage 25^ entirely tentative and subject to modification in the light of the committee's findings. The first point to be settled is the nature of the termite concerned. Control of Wood-dwelling Termites in Old Structures 1. Look for nearby source of infestation in dead portions of living trees, other buildings, fence posts, or poles. These should be elemi- nated if at all possible, or reduced to a minimum to prevent annual reinfestation. 2. All infested timbers should be removed and burned. Where this is impossible or inadvisable, relief may be sought by the intro- duction of paris green by bellows, or of orthodichlorobenzene. In case of recent infestation where workings are so small as to make this difficult, watchful waiting would seem to be best. Control of Subterranean Termites in Old Structures 1. The timbers in or on the ground should be removed if possible and insulation accomplished. 2. Where this is impossible, palliative measures may be resorted to, such as treating the timbers with creosote or sodium arsenite and the ground near them with sodium arsenite or other poisons, but this treatment may be ineffective in reaching the colonies. Infested Wood Should be Burned Numerous instances of spread of infestation by means of such wood have come to the attention of the Termite Investigations Com- mittee. Storing infested wood in cellars is dangerous, not only because of termites, but because of danger of beetle attack. Preventive Measures for New Construction 1. All refuse wood, such as stumps, roots, and loose pieces (see fig. 9), should be removed from the site. 2. The ground of the building site should be treated with some poison such as 5 to 10 per cent aqueous solution of sodium arsenite, or with crude oil. The earth under and just inside the foundation particularly should be so treated. (Note ! These are destructive to vegetation, and the sodium arsenite is a dangerous poison.) 3. All wood, set in or on the ground, should be thoroughly impreg- nated with coal tar creosote, to insure preservation, wherever the investment justifies the expenditure. 26 University of California — Experiment Station Fig. 22. Subterranean termites attack buildings by entering from the ground. The most important means of protection against them, therefore, is to insulate the wooden structures of the building from the ground. This involves imjjenetrable foundations. But impenetrable foundations sometimes crack, and such a crack makes an especially favorable passageway for the termites from earth to wood. To obviate this a metal termite shield as crudely diagramed above may be used. The projecting and overhanging edge is designed to prevent them from building their covered ways over the foundation to the wood, or at least to bring them out into the open if they do build over the projecting edge. si fl ~- Solid Block Bridging - ■fletat SkuU Fig. 23. The plans given above for proofing an ordinary house against subterranean termites embody the best methods that we know at the present time. In central and northern California present conditions do not seem to demand so great a ground clearance nor the projecting termite shield, but it would seem the part of wisdom to insure against eventualities. Cm. 314] Termites and Termite Damage 27 4. All untreated wood, at least in southern California, should be at least 24 inches above ground (figs. 23, 24). In northern California, the height may be reduced, but this increases the danger of earth contacts. Constant supervision will be required to prevent banking of earth against this protective foundation outside and underneath the building. Gardeners and plumbers should be warned and watched to this end. Fig 24 Stucco houses with enclosed wood seem especially vulnerable to termite attack. The plans given above for proofing a stucco house against the attack of subterranean termites have been modified somewhat from those ordinarily in use by the suggestion that the stucco be discontinued at the foundation level, the color effect being maintained by a color wash on the concrete foundation. 5. All pipes from ground to wood are potential pathways for entrance, and some step should be taken to obviate this, such as coat- ing the pipes with tree tanglefoot. Pipes running through concrete foundations should have a metal collar soldered to them and set in concrete. 6. Particular care should be taken in case of supporting pillars and porches to avoid exposure of wood to contacts with the earth, especially those due to laying of concrete floors at varying levels. 7. To prevent entry through cracks in concrete, a continuous, inverted, channel-shaped metal shield of heavy, galvanized iron may be placed between the foundation and the wooden sill (figs. 22-24). 28 University of California — Experiment Station FURTHER LITERATURE ON TERMITES Banks, N. and Snyder, T. E. 1920. A revision of the Nearctic Termites (Banks) with notes on Biology and Geographic Distribution (Snyder) Bulletin 108, United States National Museum. (Complete bibliography through 1919.) IIegh, emile,. 1922. Les termites, partie generate. Deseription.-Distribution geographique.- Classification.- Biologic- Vie sociale.- Alimentation.- Constructions.- Rapports avec le monde exterieur. Bruxelles, Impr. industrielle & financiere. Oshima, M. 1920. Formosan termites and methods of preventing their -damage. Philip- pine Journal of Science, vol. 15, No. 4. Snyder, T. E. 1926. Prevention of damage by termites or white ants. Farmer's Bui., U. S. Dept. Agric, No. ]472. Snyder, T. E. 1915. Biology of the termites of eastern United States, with preventive and remedial measures. Bureau of Entomology Bulletin No. 94, Part II. Snyder, T. E. 1928. Termite pole damage in California. Electric West, vol. 60, no. 3, pp. 135-138. Further Information Where further information seems called for or where some par- ticularly interesting or important cases of termite damage are encoun- tered, communicate with the Termite Investigations Committee's sub- committee on Biology, 216 Zoology Building, University of California, Berkeley, California. Send specimens if possible. If the circumstances seem to warrant it, one of the Committee's field biologists may be sent to investigate. Where this is not possible or does not seem necessary, full advice will be given. If you have information concerning termite damage in any locality or if you desire advice in case of termite damage, fill out the blank below, tear off the page and mail to Room 216, Zoology Building, University of California, Berkeley, California. In case of termite attack the committee will gladly cooperate to the extent of its knowledge. If the extent or nature of the attack seems to warrant it, a field biologist will be sent, when possible. In other cases, advice will be given by letter or by means of published articles. Name and address: Place collection was made, street, number and city: What kind and what part of structure was attacked! Any other information concerning the attack, including the kind of lumber, age of structure, ground connections of wood, and whether ground was damp or dry. If anything other than buildings was attacked, give name and extent of damage done. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION BULLETINS No. No. 253. Irrigation and Soil Conditions in the 397. Sierra Nevada Foothills, California. 262. Citrus Diseases of Florida and Cuba 398. Compared with those of California. 400. 263. Size Grades for Ripe Olives. 402. 268. Growing and Grafting Olive Seedlings. 405. 277. Sudan Grass. 406. 278. Grain Sorghums. 407. 279. Irrigation of Rice in California. 283. The Olive Insects of California. 304. A Study of the Effects of Freezes on 408. Citrus in California. 409. 310. Plum Pollination. 313. Pruning Young Deciduous Fruit Trees. 328. Prune Growing in California. 410. 331. Phylloxera-resistant Stocks. 335. Cocoanut Meal as a Feed for Dairy Cows and Other Livestock. 411. 343. Cheese Pests and Their Control. 344. Cold Storage as an Aid to the Mar- 412. keting of Plums, a Progress Report. 346. Almond Pollination. 347. The Control of Red Spiders in Decid- 414. uous Orchards. 348. Pruning Young Olive Trees. 415. 349. A Study of Sidedraft and Tractor 416. Hitches. 350. Agriculture in Cut-Over Redwood 418. Lands. 354. Results of Rice Experiments in 1922. 419. 357. A Self-Mixing Dusting Machine for Applying Dry Insecticides and Fun- 420. gicides. 361. Preliminary Yield Tables for Second 421. Growth Redwood. 423. 362. Dust and the Tractor Engine. 363. The Pruning of Citrus Trees in Cali 424. fornia. 364. Fungicidal Dusts for the Control of 425. Bunt. 426. 365. Avocado Culture in California. 366. Turkish Tobacco Culture, Curing, 427. and Marketing. 367. Methods of Harvesting and Irrigation 428. in Relation to Moldy Walnuts. 368. Bacterial Decomposition of Olives During Pickling. 429. 369. Comparison of Woods for Butter 430. Boxes. 431. 370. Factors Influencing the Development of Internal Browning of the Yellow 432. Newton Apple. 371. The Relative Cost of Yarding Small 433. and Large Timber. 373. Pear Pollination. 434. 377. The Cold Storage of Pears. 380. Growth of Eucalyptus in California 435. Plantations. 385. Pollination of the Sweet Cherry. 386. Pruning Bearing Deciduous Fruit Trees. 436. 387. Fig Smut. 388. The Principles and Practice of Sun- 438. Dryine Fruit. 389. Berseem or Egyptian Clover. 439. 390. Harvesting and Packing Grapes in California. 391. Machines for Coating Seed Wheat with Copper Carbonate Dust. 392. Fruit Juice Concentrates. 440. 393. Crop Sequences at Davis. 394. I. Cereal Hay Production in Cali fornia. IT. Feeding Trials wit! i42. Cereal Hays. 443. 395. Bark Diseases of Citrus Trees in Call fornia. 444. 396. The Mat Bean, Phaseolus Aconitifo lius. 445. Manufacture of Roquefort Type Cheese from Goat's Milk. Orchard Heating in California. The Utilization of Surplus Plums. The Codling Moth in Walnuts. Citrus Culture in Central California. Stationary Spray Plants in California. Yield, Stand, and Volume Tables for White Fir in the California Pine Region. Alternaria Rot of Lemons. The Digestibility of Certain Fruit By- products as Determined for Rumi- nants. Part I. Dried Orange Pulp and Raisin Pulp. Factors Influencing the .Quality of Fresh Asparagus after it is Har- vested. Paradichlorobenzene as a Soil Fumi- gant. A Study of the Relative Value of Cer- tain Root Crops and Salmon Oil as Sources of Vitamin A for Poultry. Planting and Thinning Distances for Deciduous Fruit Trees. The Tractor on California Farms. Culture of the Oriental Persimmon in California. A Study of Various Rations for Fin- ishing Range Calves as Baby Beeves. Economic Aspects of the Cantaloupe Industry. Rice and Rice By-Products as Feeds for Fattening Swine. Beef Cattle Feeding Trials, 1921-24. Apricots (Series on California Crops and Prices). The Relation of Rate of Maturity to Egg Production. Apple Growing in California. Apple Pollination Studies in Cali- fornia. The Value of Orange Pulp for Milk Production. The Relation of Maturity of Cali- fornia Plums to Shipping and Dessert Quality. Economic Status of the Grape Industry. Range Grasses of California. Raisin By-Products and Bean Screen- ings as Feeds for Fattening Lambs. Some Economic Problems Involved in the Pooling of Fruit. Power Requirements of Electrically Driven Manufacturing Equipment. Investigations on the Use of Fruits in Ice Cream and Ices. The Problem of Securing Closer Relationship Between Agricultural Development and Irrigation Con- struction. I. The Kadota Fig. II. Kadota Fig Products. Grafting Affinities with Special Refer- ence to Plums. The Digestibility of Certain Fruit By- Products as Determined for Rumi- nants. Part II. Dried Pineapple Pulp, Dried Lemon Pulp, and Dried Olive Pulp. The Feeding Value of Raisins and Dairy By-Products for Growing and Fattening Swine. Laboratory Tests of Orchard Heaters. Standardization and Improvement of California Butter. Series on California Crops and Prices: Beans. Economic Aspects of the Apple In- dustry. BULLETINS — (Continued) No. 446. 447. 448. 449. 450. 451. 452. 453. 454. No. 87. 115. 117. 127. 129. 164. 166. 178. 202. 203. 209. 212. 215. 232. 239. 240. 241. 243. 244. 245. 248. 249. 250. 252. 253. 255. 257. 258. 259. 261. 262. 263. 265. The Asparagus Industry in California. The Method of Determining the Clean Weights of Individual Fleeces of Wool. Farmers' Purchase Agreement for Deep Well Pumps. Economic Aspects of the Watermelon Industry. Irrigation Investigations with Field Crops at Davis, and at Delhi, Cali- fornia. Studies Preliminary to the Establish- ment of a Series of Fertilizer Trials in a Bearing Citrus Grove. Economic Aspects of the Pear In dustry. Series on California Crops and Prices: Almonds. Rice Experiments in Sacramento Val- ley, 1922-1927. No. 455. Reclamation of the Fresno Type of Black-Alkali Soil. 456. Yield, Stand and Volume Tables for Red Fir in California. 457. Series on California Crops and Prices: Oranges. 458. Factors Influencing Percentage Calf Crop in Range Herds. 459. Economic Aspects of the Fresh Plum Industry. 460. Series on California Crops and Prices : Lemons. 461. Series on California Crops and Prices: Economic Aspects of the Beef Cattle Industry. 462. Prune Supply and Price Situation. 463. Series on California Crops and Prices: Grapefruit. 464. Drainage in the Sacramento Valley Rice Fields. Alfalfa. Grafting Vinifera Vineyards. The selection and Cost of a Small Pumping Plant. House Fumigation. The control of Citrus Insects. Small Fruit Culture in California. The County Farm Bureau. The Packing of Apples in California. County Organization for Rural Fire Control. Peat as a Manure Substitute. The Function of the Farm Bureau. Salvaging Rain-Damaged Prunes. Feeding Dairy Cows in California. Harvesting and Handling California Cherries for Eastern Shipment. The Apricot in California. Harvesting and Handling Apricots and Plums for Eastern Shipment. Harvesting and Handling California Pears for Eastern Shipment. Harvesting and Handling California Peaches for Eastern Shipment. Marmalade Juice and Jelly Juice from Citrus Fruits. Central Wire Bracing for Fruit Trees. Vine Pruning Systems. Some Common Errors in Vine Prun- ing and Their Remedies. Replacing Missing Vines. Measurement of Irrigation Water on the Farm. Support for Vines. Vineyard Plans. Leguminous Plants as Organic Fer- tilizers in California Agriculture. The Small-Seeded Horse Bean (Vicia faba var. minor). Thinning Deciduous Fruits. Pear By-Products. Sewing Grain Sacks. Cabbage Production in California. Tomato Production in California. Plant Disease and Pest Control. CIRCULARS No. 266 Analyzing the Citrus Orchard \>y Means of Simple Tree Records. 267. The Tendency of Tractors to Rise in Front; Causes and Remedies. 269. An Orchard Brush Burner. 270. A Farm Septic Tank. 273. Saving the Gophered Citrus Tree. 276. Home Canning. 277. Head, Cane and Cordon Pruning of Vines. 278. Olive Pickling in Mediterranean Countries. 279. The Preparation and Refining of Olive Oil in Southern Europe. 282. Prevention of Insect Attack on Storerf Grain. 284. The Almond in California. 287. Potato Production in California. 288. Phylloxera Resistant Vineyards. 289. Oak Fungus in Orchard Trees. 290. The Tangier Pea. 292. Alkali Soils. 293. The Basis of Grape Standardization. 294. Propagation of Deciduous Fruits. 295. Growing Head Lettuce in California. 296. Control of the California Ground Squirrel. 298. Possibilities and Limitations of Coop- erative Marketing. 300. Coccidiosis of Chickens. 301. Buckeye Poisoning of the Honey Bee. 302. The Sugar Beet in California. 304. Drainage on the Farm. 305. Liming the Soil. 307. American Foulbrood and Its Control. 308. Cantaloupe Production in California. 309. Fruit Tree and Orchard Judging. 310. The Operation of the Bacteriological Laboratory for Dairy Plants. 311. The Improvement of Quality in Figs. 312. Principles Governing the Choice, Op- eration and Care of Small Irrigation Pumping Plants. 313. Fruit Juices and Fruit Juice Beverages. 314. Termites and Termite Damage. The publications listed above may be had by addressing College of Agriculture, University of California, Berkeley, California. 26m-4,'29.