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This Kwn ■• filiiMd at tlw raduetion ratio ehackwl bttow / C« docunwnt Ml film* au tsux d* rMuction indiqu* ci- d at s ow . lOx 14x ita 22x 26x MK y 12x 16x 20x 24x 28x 32x Th« eopy flimad hun to ttM gwMrosity of: IMS bswi fspcPwiccd QMnks Llnry AgrieuHurt CanMta POmHMc ooiMidM'inf of tiM origifMl eopy quality eofioitioii MM wflipility in kflcpin9 with ttM OrigiiMl eeplM in printad papar eovara ara fHnMd bag l nnin g whh tha front cevar and anding en ttM laat paga viHth a prtntad or iNustratad impraa- •ion, or tho bacic eovar whan a ppropr ia ta. All othor original eopioa ara filnMd baginning on tho firat paga with a printad or illustratad impraa- •ion. and anding on tha laat paga with a printad or muatratad imp r aaaion. L'axaniplaira film* fut raproduit griea i la g«n4ro8it« do: BibliothkpM Afrioultur* Canada Laa Im a gaa aulvantaa ont 4tA raproduitaa tive la plua grand coin, eempto toiM do la condition at da la natMti da Taxampiaira Aim*, at an ee nfe rm it* avae laa eonditiona du contrat da fllnMga« Laa aKampiairaa originaux dont la eouvartura tt papiar aat imprimda aont fiimda an commandant par la pramiar piat at an tarminant soit par la d amitra paga qui eomporto uno amprainta di m praaaion ou dlHuatration. soit par la aacond plat, a alon la eaa. Teua laa autraa axampiairaa originauji aont fiimda an commofMant par la pramiAra paga qui eomporto uno amprainta dimpraaaion eu dlHuatration at an tarminant par la damMra paga qui eomporto uno toHo amprainta* Tha laat raoordod ahall contain tha TINUEO"). or tho frama on aach mloroflcha lymbol •^(moaning "CON- aymbd ▼ ( m ea n i n g "INO"). Un dee aymbolee suiventa apparattra sur la demMre imege do cheque mierofiche, seion le eaa: la aymboie — *> tignifie "A SUIVRE", le aymbole y aignifio "FIN". Mope, pletee. cherta. ate., may Im Mmed at d i fferent reduction ratioe. Thoae too lerge to be entirely inehided in oim eapoeuro are fHmed begkming in the upper left hand comer, left to right and top to bottom, aa many framee aa required. The following diagrama iNuatrata the method: 1.00 eartee. planchee. taMeeux. etc.. pauvent Atra fHmde A dee taux da rdduction diffArants. Loraque le document eet trop grand pour Atra raproidult en un soul clichd. ii aat fHmA A partir do i'angia aupdrieur gauche, do gauche A droite. et do iMut en bee. en prenent le nombre dtmegee nAceaaaire. Laa diagrammea suiventa iHuatrentla nMthode. 1 2 3 1 2 3 4 5 6 MKXocorv MMunnN mt chait (ANSI and ISO TEST CKAKT No. 2) A /APPLIED IN/MGE In ^Ki 16^^ Ea«t Uoin Strtct Roch«t»f, Ntw York 14609 USA (716) 482 - 0300 - Phont <716) 286 -5989 -Fox DOMINION OF CANADA DEPARTMENT OF AGRICULTURE ENTOMOLOQICAL BRANCH 0. OOflDON HCWITT. DOM'MIQN CNTOMOLOQWr THE ARMY CUTWORM Bttxoa {Chorizagrotia) atuciliaris Grotk. BY B. H. STRICKLAND, M.Sc Field Officer BULLETIN l^o. 13 niMWMd by direotion of Hon. MARTIN BURRELL, Minlatar of AariouKur*, OtUwa OTTA ,/A qOTERNMENT FRINTINO BCRBAV 1916 C212 ^ i wipmiwrrii DOMINf^N OF CANADA DEPARTMEN JF AGRICULTURE ENTOMOLOGICAL BRANCH C. QOnOON HEWITT, DOMINION CNTOMOLOQI8T THE ARMY CUTWORM Euxoa {Chorizagrotis) auxiUarin (Jr(»te. •y E. H. STRICKLAND, M.Sc. FiflJ Officer BULLETIN No. 13 Published by direction of Hon. MARTIN BURRELL, Minister of Agriculture, Ottawa OTTAWA GOVERNMENT PRINTING BUREAU 1916 94641—1 NOTE. All inquiries relating to inHet-t pestn, and packages (up tu 1 1 oun(>er< in weight) containing specimenfl may l)e mailed "Free" if addrexKed to the Dominion EntomologiBt, Department of Agriculture, Ottawa. In all cases where it u posmble, living HpccimonH of the insects should l>c sent inclosed in a sirong wooden or tin box to prevent damage in transit. Living insects should be supplied with a liberal quantity of their food plant, and in all cases they should be carefully packed. The name and address of the sender should >>(■ written on the outside of the package, and a letter giving as full details ah possible nhould iu all cases accompany the insects «ent in for report. Farmers in the Prairie Provinces may communicate with either of the following Field Officers: Mr. E. H. Strickland, Dominion Entomological Labora- tory, Lethbridge, Alta.; or Mr. Norman Criddle, Dominion Entomological Laboratory, Treesbank, Man., regarding insect injuries, particularly in cases of emergency. Letters and packages to these officers must bear postage and cannot be mailed free. Ottawa, Mhp I> 1, 1916. To the Honouruhlc Thi* Minb cr of A^rirulturp, Ottawa. Sir, — I have the honour to oubmit for your approval, KntomoloKicnl Bulletin No. 13, entitled "The Army Cutworm," whieh haw been written by Mr. E. H. Strirkland, Field Oftieer in charge of the Entomological Lalmratory at Lethbridge, Alta. The Army Cutworm, which Hhould l>e dintinguiKhed from the true Army Worm, in new to Canada an a field pest, although we have previouo recordn of minor injuries by thix 8perie». In 1916 an exten<M Advlu .tioB. lUkiti H*bit> ii( ttm Urv* . . . HilirniattiHi FlllMi plMlk rMdiM habltn Micntiba n( i)h> larv» mkI twhavhwr to liahl Plipatkm Habilii a( Ihr molhi Emi-rvBi'p Dnlrii ••( flight . Allnii'tioB tu liaht mad buildinca Katranrc intn hoaxxi . . Maluriitkm t^ lhi> ovaritM Ovipuailitm vw' Dalonfo'. .•■ IxH-aiioa ol I Namhor ol tat laid by aa ladividaal moth Leacth of CM atMe. . Nambwol bromU Natanu eaemiM I'radaton PknwitM. . Uiaeaam Methoda ol roatrol , Preveative ni>>aiiuni« < 'Iran nummiT-lallow Kemedial meaauiw , Poimned baiu Trap (ttrtowa C'oBitruction ol trap funuwi . Poiioaed bait in trap (urrowK Ptiifinnl •horta IN>iraBed voKftlation Efforta d raanibaliam upon poiMtning in lurrowa. . C'omparativo valup ol pniaoning in lurrowa aad brc. Number and luration lA (urniwn Maiatenanre ol lurrowa. . Cprayinc allalla Irrigation ditrhea Control miwauma rometimm l«roniineode> Trapping in ptwt holm Lantern trap* lor the r ^ iilr< Rolling Arknowleilgmenta Literature i«lerr«d to in text atiag »it uaauitable to prairitt roaditiona tm». 9 9 9 W 10 II II II II M ■I 14 14 14 M l« 10 10 ir 17 17 M M to 10 10 10 a n 13 n u » 24 H M M M s » m ao ao » ILLUSTRATIONS. Page. Fig. 1.— Army Cutworm ogxa. 80 times natural »i«e 9 2.— Full-grown Army Cutworm. Twice natural ai»e 9 3. — The ' iirec varieties o( Army Cutworm moths: var. auiiliarh. var. Mrofrrena and var. agrettia. Natural sixe II 4. — Twig of Manitoba maple with bark eaten off by Army Cutworm!^. Natural siie 12 h. — Earthen cell in which the cutworm pupates. Natural sixe 14 6.— Diagram showing the nightly rapture of Army Cutworm moths in 1914 18 7.— Diagram showing the nightly capture of Army Cutworm moths in 191.1 18 8. — Caloaoma tepidum: a larva, h adult. Natural sixe 20 9. — Apanlrlff lamcept Ashm. 8 times natural sixe 21 10. — Meteorui sp. 8 times natural sixe 21 1 1 . — Berecyntut bakeri How. var. nixoa. 20 times natural sixe 22 12.— Diagram of vertical-sided furrow 25 13.— Diagram of dusty-sided furrow 28 14.— Preparing a dusty-sided furrow 26 15.— Applying poisoned slinkwecd to a dusty-sided furrow 27 THE ARMY CUTWORM. Euxoa (Choriiagrotis) auxiliaria Grote. By E. H. Strickland, Field Officer, Dominion Entomological Laboratory, Lethbridge, Alberta. SUMMARY. The Army Cutworm (Euxoa auxiliaris) is new to Canada as a field pest, though it was recorded as doing damage to gardens in 1903. Since 1898 it has been a frequently recurring field pest in the state of Montana, where it has caused considerable damage. In 1915 an extensive outbreak of this insect occurred in Alberta, and covered a territory of about 3,000 square miles. The cutworms are variable in appearance, some of them being almost black, while others resemble the Red-backed Cutworm (Euxoa ochrogaster), although the back is more yellowish and striped (page 9). The eggs are laid in the autumn, upon weedy fields. They hatch before winter sets in, and the cutworms may be half grown before the ground freezes up. They are dormant throughout the winter, and remain in the soil until the spring (page 11). Soon after the frost is out of the ground they come to the surface and feed freely upon the weeds. When the cutworms are numerous they soon destroy all of the weeds upon the fields where they hatched and have passed the winter. Then, like the Army-worm, they move off more or less in a body, in search of more food (page 13). In all of the cases that we have observed, their general line of march has been towards the northwest. Light appears to direct the larval migration (page 13). The larvie are strongly attracted to artificial light, and can be captured at night in lantern traps. The food plants include practically all weeds, all field crops such as grain, flax, beets, alfalfa, etc., as well as garden crops (page 12). When food is scarce the larvae become very cannibalistic, and feed freely upon each other. The larvte do not feed from below the surface of the soil as do the common cutworms (page 12). By the middle of May the most advanced larvse have matured, but the majority of them do not form cells until about the first week of June. Most of them transform to the pupal stage within their earthen cells in about twelve days' time (page 14). The moths fly from the middle of June till the end of September or early in October. They may a'stivate during the hottest part of the summer and so appear to be double brooded (page 19). These moths, with tho.se of Nodua clandestina, constitute a most annoying domestic pest. Most of them enter houses between the shingles or though cracks around doors and windows. They are not very strongly attracted by light, and the majority do not enter houses because of the lights in them (page 16). Light traps in the field are not a satis- factory means of control, for they capture very few of these moths (page 16). The eggs are laid from the last week in August to the middle of October. Although apparently most of them are laid in the soil, the moths always choose places where there is plenty of green growth near which to lay eggs (page 17). Weedy summer-fallow is a specially favourable place, for the moths hide under 8 the clods by day (page 23). Fallow land can be kept unattractive to all cut- worm moths by destroying »11 green growth on it from the last half of August to the end of October. The destruction of larvae by poison can be accomplished with comparative ease. This is done most economically by the use of a poisoned bait applied to specially prepared furrows. In wet seasons vertical-sided furrows can be used (page 25), but often these cannot be employed, since the soil is usually too dry for their construction without expensive hand labour. Under such circumstances they can be replaced with dusty-sided furrows (page 25). The furrows are made around clean fields which are to be protected. If the fields are already infested, supplementary furrows may have to be made through them (page 28). Two classes of bait may be used as carriers of the poison. They are shorts sweetened with molasses (page 2b), and green vegetation. For the latter the best results have been obtained with stinkweed, or alfalfa (page 27). A method of destroying the larva by the use of irrigation ditches has been evolved in Montana. This might be used where water is available during an army cutworm outbreak (page 29). INTRODUCTION. The spring of 1915 was marked, in southern Alberta, by an outbreak of a cutworm which was almost unknown, previously, as a species of economic importance in Canada. This cutworm is the larva of the noctuid moth Euxoa (Chomagrotia) auxiliaria Grote. Three fairly well-defined varieties of this moth have been described as three distinct species. These are E. auxiliaria (s.s.) Grote, E. introferena Grote, and E. agriatia Grote. Observers who have studied long series of these moths have doubted the validity of these species, and Mr. F. H. Wolley Dod now tells me that breeding experiments conducted by himself and Mr. W. H. T. Tams leave little doubt as to the specific identity of the three varieties. The species is a native of North America. It occurs most abundantly on the western prairies, though it extends as far east as central Manitoba, while a specimen of the moth has been taken in Mexico. It has never, however, been recorded as a pest of much economic importance at a distance of more than a hundred miles east of the Rocky mountains. This cutworm appeared, for the first time, in the literature of economic entomology m 1898, when Wilcox described a serious outbreak of the larva in the Missoula and Bitter Root valleys of Montana. He proposed for it the popular name of an Army Cutworm, on account of the migratory habits assumed by It being similar to those of the true Army-worm {Cirphia unipuncta). From that date to the present the reports of the Montana State Entomolo- gist have recorded local outbreaks on various occasions, culminating with an account of an "almost statewide" outbreak in the spring of 1915. At this latter date the larvae appeared for the first time in sufficient numbers to constitute a menace to the grain and other crops of southern Alberta. Inquiries regarding them were received from farmers in a district of about 3,000 square miles in extent. Infestations were particularly heavy in the Ravmond and the Bow Island districts. On one previous occasion only had the larvae been sufficiently abundant -n Canada for this insect to be regarded as one of economic importance. In 1903, Fletcher recorded it as injurious to gardens in Calgary and Regina. In the same year, Gillette reported an outbreak in Colorado, though on this occasion there is no record of their attracting attention in Montana. The references cited above comprise all that has been written on the biology of tjie species. In these accounts there is no record of the larvae being present m destructive numbers for two years in succession. It is highly improbable, therefore, that the Army Cutworm is a pest that \/e shall have to fight annually, even though it appeared this year in such large numbers that it constituted a serious menace to grain fields in Alberta. It is liable, however, to occur at any time in sufllciently large numbers to warrant the adoption of efficient control measures. DESCRIPTION OF THE STAGES. Eggs. (Fio. 1.) These are nearly Rlobular, but are a little fluttenef ^ye* «"« "'ong the clypeal sutures ; wX^w" ^if"°j:i' r t^'' 'V''^ •"""i"'- ^\' *•"« Prothoracic shield is dark greenish-pey, mottled ™ln.,r^'fhfKJ{S''/"/'r*'* "' '^^^ ""? r**" "" indefinite white mediSline. -Ke general witZwhif/J^i^n I •'*"'', ^'^^^ '"J*^ " ^."" '"'^y ^T"" """led with reddish4)rown. and Tl V m.^itH^ri'"C °^ '""^"'? '"tensity running the length of the body. This line is gener- shLrw^lfl™. . ""'i*'**"- Laterally, the body is dark olive green mottled with a lighter Tl,„ ! Jil 1 " T*'"'. °J, '". *'"'e, ""^es » double, indefinite light line along its entire length, the iZIS^fe^^H' T^ '''"^''' "Ji:' a-t ».'tu»ted on a lighter creamy band which merges fnto [...iPi. ^K ^° f ^^^ ^''^^"^ *•"?"«•» '* ." 'i'^'T'y contrasted with the dark green of the laterals. The tubercles are not prominent, those on the dorsum are black and shining, while f-^t^^^'^'^^V^'fi'"* "'? ''•'^' "^r"- *"«"" e""-*" ari«e« » «hort, black hair. The tnief^J are .S^: w i»i "^*' ?*"! °i P^?i^ T provided with lateral plates of green ehitin. Thranal shield 18 but little contrasted with the body colour, and has a w^ll-defined median line. This type of larva is sometimes much like that of the common Red-backed eutworm {Euxoa ochrogaster) , from which it is distinguished by its more dull coloration, especially that of the dorsum, which is more yellowish and mottled, by the dark margins of the median line which give it a more striped appearance, and by the more extensive mottling on the head. Another variety of the larva, which is almost as common as the above, has the dorsum almost entirely dark green, though on the posterior half of each segment there are two creamy patches. Still other larvte are found in which all pigment is reduced, and the dorsum 18 almost white. AH of these varieties intergrade, and since among the larvae from one moth s eggs nearly all degrees of variation are found, while all of the three varieties of moths can be bred from any variety of larva, it is seen that larval and adult variations are not specifically correlated. Pup^. The pupa are indistinguishable from those of other species of this genus, and of the closely related genera which we have studied. The length varies, but it 18 usually about two-thirds of an inch (17 to 18 mm.), while the diameter at the base of the thorax is about one-fifth to one-quarter of an inch The colour varies according to the maturity of the pupa and to the variety of the inclosed moth. When first disclosed the pupa is light straw yellow, but when ™5 •'i''fu''^™Y be pitchy black if it contain a dark auxiUaris s.s. adult, or chestnut red If the inclosed moth is of the agrestia variety. The cremastral spines are very variable in disposition and shape, though in most normal pupse they consist of two stout spines. These may be close set, or wide apart, strongly divergent or parallel, and occasionally they are set on a prominence. They tend, however to be more often closely set, and to run parallel, than in other related species. One or more subsidiary spines may be present. Since the pupse of our common Iielrt and garden cutworms show these variations also, we have found no method of distinguishing vvith certainty those of any one species of the Euxoa group from the other related forms. In all species we have been able, however, to distin- guish the sex by the position of the genitalia. The disposition of the female genitalia on the pupa indicates that it consists of the external organs of three segments, whereas that of the male is confined to a single segment Adults. (Fig. 3.) The moths of this species, as previously stated, are very variable in appear- ance and no attempt will be made hen- to give technical descriptions of the varieties. They are fairly uniform in size, and the spread wings are usually between IJ inches and Ij inches in expanse. The antenna of both sexes are 11 filiform, but the sexes can UNually b«! separated bv the males havinu a more reddwh or brown tmge than the females, in whieh sex grey prtHlominates. When at rest the wmgs are folded flat over the body. Fig. 3.-The three varietic. ol Army Catworra moths: var. auxUiariH. var. introUren,. an.l var. agresli. Natural 8i»e. (Original.) HABITS. Habits of the Lar\\e. K . ^nder artificial conditions all of the eggs obtained from captive moths'have hatched between heptember 10 and October 27, and it is probable that some- where withm the range of these dates the majority of young larvse appear under natural conditions. We liave made repeated efforts to find them in the field during the autumn of 1915, but without success. Cooley (1908) states that in Montana the young larva' hide in stools of wheat, and do not avoid the light us noticeably as they do when they are larger. HlUERN.VnON. At the approach of winter the larva, manv of which are then half grown become dormant and remain in or on the soil until the si,riiig davs are sufficientlv warm to bring them to life once more. The winter is not passed in any • v-ial stage, for the larvsp from one batch of eggs develop with surprising irreg v in the fall and when their activity is suspended bv cold, those from di, nt batches of eggs may be in any stage from the earliest to about half grown. I ooley states also that they do not hibernate in speciaiiv constructed cells, and that some farmers report finding them between the snow and the soil, while at other times they are 2 to 3 inches deep in the soil. Our attention was drawn to th. m fir.4, in 1015, on April 3, when numerous specimens had b-en attracted over night to the electric light at the main entrance of the provincial jail at Lethbridge. They varied in size from one-quarter inch to nearly 1 inch in length. Since at this date the frost had been out of the ground 94641— 2§ 12 for two or three days only it is evident that they had hibernated in several stages. During the next few days we received reports from various quarters of an alarming abundance of larve in fields which were being prepared for spring FOOD PLANTS. Infested fields examined at this time contained a mixed growth of tansy mustard (Siaymbrium inciaum), tumbling mustard (Siaymbrium nltiaaimum), volunteer fall wheat, prairie grasses, and patches of stinkweed (ThL.spi arvenae). Although subsequent observations showed that the Army Cutworm will feed upon practically all green growth, it was seen at this time that they showed a marked preference for tansy mustard and stinkweed. Fall wheat and tumbling mustard were almost untouched until the fields had been practically denuded of the other weeds, while prairie grasses were eaten only as a last resource. In 1898, Wilcox gave a list of forty-two food plants besides native grasses. Our observations this year have brought up the number to fifty-one, chic of Fig. 4.— Tvig or Manitoba Maple with bark eaten off by Army Cutworms. Natural siic. (Original.) which are: wheat, oats, rj'e, barley, alfalfa, clovers, all vegetable crops in infested gardens, foliage of fruit trees, stinkweed, all mustards, lamb's quarters, and willow sage. In addition to the above we received two accounts from Purple Springs of damage to Manitoba Maple seedlings (fig. 4) by these larvae. They ascended the young trees and fed freely upon the bark of the smaller branches. Several trees were killed in this manner. We obtained some of the damaged twigs, together with the larvae taken upon them, and the latter were bred through to maturity in order that we might establish their identity. FEEDING HABITS. Unlike the more common prairie cutworms, the Army Cutworm feeds above ground, and '.las never been seen to attack a plant from below the surface of the soil. When food is scarce it will sometimes follow a plant upon which it 18 feeding down into the soil. This is unusual, and when food is plentiful the larvae feed most extensively upon the leaves only, when they are attacking grain crops. The subterranean feeding species of cutworms almost invariably kill all of the young plants that they attack, and they feed to so small an extent on each of them that they destroy a large number before their appetites are satisfied. When, on the other hand, army cutworms are present in their normal small nunibers the damage they do individually is slight, for with abundance of food they usually do not destroy the growing point of a plant and, therefore, though development is retarded to some extent, the majority of these plants will survive the attack. In years such as 1915, when on some fields these 13 oatrrpillnrs were so numerous that there were 1(K) to lo() of them to ;. ure foot, they will, however, consume all available fcxid rapidly and eompleti^ MUiKATION or LARV^ AND BEHAVIOUR TO LIGHT. As soon as the food supply is rxhuusted the larvjp, as though by common consent, leave the stripped fields where they passed the winter and minrate more or less in a body in search of pastures new. We do not know for certain what factors control their course of miKiation, but it is evident that somethinK very dehnite causes each individual to take up a general line of march and hoUl to It with little variation. The guiding principle appears to Iw that of light 1 hey are certainly positively phototropic to artificial light at night time We proved this by setting out in an infested field a numln-r of 18-inch pans, in some of which we placed lanterns. The pans were all sunk in the ground so that the rim was level wth the surface of the soil. Each was partly filled with coal oil h-ach of four pans, provided with lanterns, caught on an average 850 larvw a night, wherea.s similar pans without lights captured an average of 94 larvae This attraction to light was demonstrated also at Bow Island, where the streets are lighted with natural gas. Although the larvas were not sufficiently numerous in the immediate vicinity of the town to attract general attention they swarmed in dense masses under every street lamp, covering an area of about SIX feet in diameter. *i. *J^^T".""'"J"?*r,'"" experiments were made, the larvae ranged from alwut the third stage to full grown, and the various stages were found in the oil in alxjut the same proportions whether a light had been placed in the pans or not. From this It would seem that all of the stages found in the spring are similariy oriented by light. It has been noticed both here and elsewhere that the larvie usually remain below the soil fcom sunrise until alwut 4 or 5 p.m., when they come to the surface in search of food. At this time the sun has lost most of its strength and It IS seen that the general migration is towards it. Thus their course of migration at this time is towards the west. Usually the larvae hide from the direct rays of the sun when it is high The reason is, apparently, that at such times the light is too powerful for them and it.s action has changed from one of attraction to one of repulsion. Normally' then, they remain below ground during bright sunny days, until the sun is suflSei- ently low for its weakened rays to have lost their repelling power. When food IS scarce, however, hunger overcomes their aversion to exposing themselves U, the sun, and at such times the larvae may come above ground during the hottest part of the day. If the day be clear they will then crawl directly away from the sun, and thus travel in a northerly direction. At such times they move with great rapidity. This appears to be the explanation of the phenomenon noticed here and elsewhere that the general trend of migration is in a north- westeriy direction. There are, of course, local and temporary variations due to cloudy days and excessive migratory activity at night, but in all instances which have come under our observation the general direction of migration has been as above indicated. The distance traversed by the worms in their migration depends largely upon the abundance of food. We have not data upon this point as definite as desirable. It was seen, however, that within a week nearly all of the larvw had left a newly seeded, and therefore quite clean, quarter-section which had been protected against further infestation. Wilcox.(1898) states that in Montana an army of worms travelled 3 miles in a north-west direction between the first of April and the first week in May doing considerable damage all along the line of march ". This would indicate that there was a moderately plentiful supply of food available, and it is reason- 14 able to HuppoHP that they would have travelled over a eonMiderahly greater diHtance had the land been clean. It will Iw seen that thifi in an important point when we are oonHlderinR the quention of control. PUPATION. When the larva is full grown, and has finished feeding, it burrows into the soil for the purpose of constructing a hard-walled cell in which to trans- form into a pupa or chrysalis. Since it is necessary for the larva to have either solid or moist earth 'jr the construction of such a cell, it burrows down until such conditions are obtuined. The depth at which the cell is formed varies considerably, therefore, and it may l)e just below the surface or from 2 to 3 inches deep. The cell is oval, and, in so far as we have been able to see, it is mmlelled by the head in conjunction with a revolving motion of the whole Iwdy. The internal surface is quite smooth. The fine particles of earth are not held together by silk, though there is evidence of some other salivary secretion which cements them together though it does not make the wall waterproof. (Fig. 7.) Fi«. 8.— Earthern cell in which the cutwomi pupstoH. Natural «iie. The internal measurements of the cell are usually a little under an inch in length and half an inch in diameter. The wall varies in thickness from about one twenty-fourth inch, to one-sixteenth inch when all superfluous loose earth has been removed. These cells may lie in almost any plane in the soil. We have found them most frequently lying more or less horizontally, while Gillette (1904) found that their position in the soil was usually vertical, with the head end up. In 1915, the earliest evidence of cell formation observed was on M.iy 9, and the last captive larva to make a cell did not do so till June 15. The majority of larvae had formed cells by June 2, which appears to be al)out the average date of maturation in the field. This date refers only to the brood at Lethbridge, which we were observing, for the average tiate varied by up to a week earlier or later in neighbouring localities. The mature larvae remain for a varying period in their cells l)efore pupation. The shortest time that we have on record is four days, and the longest is seven- teen days. The average seems to he about twelve days. The first pupa was obtained in the lalwratoryon May 26, though the majority of transformations were not accomplished until June 2 to 5, lietwecn which dates about 60 per cent of the larv'ffi pupated. Our latest record was on July 1. In 1915, the length of the pupal stage varied between seven and eight weeks, and in most cases the longer extreme was approached. Two specimens of the same species were bred in 1913, and in each case the pupal period was of Uiirty days' duration only. Habits of the Moths. EMEROKNCE. From field cages in which condition:! were practically normal, it was found that recently emerged moths came to the surface at all hours of the day as well as during the night. The datps upon whlrh wventy-five adultM uppourrd uIkivp ground pxt<>ndi-d from July 19 to August 2. Over wsventy-five per rent of these emerimi between July 21 and July 27. A light trap was run in conjunction with breeding work, and from this we obtained data to the effpct that the maximum flight at Lpthbridge was (jver More our first adult emerged in the cages. Our larv» were colle«tpd mainly upon the Experimental Farm, where they were not particularly numerous. Sincp our cages were set out in connection with parasite work wp did not collp«-t larve for thpm till they were approaching maturity. The larv» thus caged cannot have been seriously affpctcd by thp handling this necessitated, and their subs(>t}uent life was such a close approach to normal that we Ik'Upvp the dates given abovp are those upon which the brood under observation would havp hatched in nature. Our light trap consisted of a half gallon mason jar "killing l)ottlp", fitted with a paper funnel, as describpd by J. D. Evans (1908). This was hung under the porch light of the superintendent's house at the Experimental Farm, and was allowpd to run all night. DATE8 OF FLIOHT. Our first catch of E. auxiliaria was made on June 15, when three specimens (one male and two fpmales) were taken. From this date up till July 13, when over two thousand moths of this species were taken in IJ hours, the nightly catch increased very rapidly. The number of moths taken varied considerablv from night to night, and the capture made on July 13 was abnormal, for the numlMT of specimens taken represented a comparatively small percentage of an innumerable swarm of moths which smothered the ceiling, walls, and pillars of the porch, and could not gain admission to our already overflowing trap. On the previous and subspqupnt nights we took, on an average, 215 moths onlv. This figure represents a normal nightly catch for the trap, such as was main- tained with considerable temporary fluctuations until alwut August 7 (fig. 7). From this date there was a steady decline until early in Septemlwr, when there was a marked increase, particularly among the males. On Septemlwr 12 there was a sudden drop in temperature to 4" F., which practically stopped the flight around buildings. Six specimens were taken, however, on September 18, after which date no more captures were made with the light trap. Specimen.s were present in the fields till early Octolier. XT • ^* '^*!^o''e stated, larvae were not verj- abundant on the Experimental Farm. Neither did any farmers, in the immediate vicinity, report their presence in such numbers as would account for over 9,000 adults being taken in a single light trap during the two weeks preceding the first emergence from larvse collected locally. It is evident, therefore, that they were the moths from some early maturing brood which had developed in a nearby place. We received, <>arlier in the year, a notification of a large mass of "worms" moving across the prairie to the north of the farm, and it is probal-le that this was the source of the flight. ATTRACTION TO LIGHT AND BUILDINGS. The moths of this species, and to a less extent those of NocUm dandedina, constitute one of the most annoying household pests in districts where they are abundant. It is practically impossible to keep them out of the houses, where they leave not only disgusting deposits on windows and furniture, l)ut in addition they have a most annoying habit of darting .irnunfl such light J «'; there may be in the house, suddenly falling into food or anything left uncovered, and also of shooting up one's sleeves or down one's neck in a most disconcerting manner. Id It m grnprally pon«;«leml that it in the lixhtH in tlip hwiMm whicli nttrnrt the m«)thinnto them. Thw, however, i* only partially true, for the n.tion of the lifhtMl lampH w for the greater part only that of ronrentrating the mothH, whu'h are already in the houw, around them. The Hwarm» of mothw wen in the eveninw* attempting to escape from windowH of ImrnM whirh are never lighted at night time ii« a proof of thin ntntement. The mothN of thin npeiien live for a remarkahlv long time In-fore the ovanen begm to develop. Thii* period Bppe«r.4 to lie in all eanen of ut lenttt thr««c monthn' duration. The fields, with their romparative lack of shelter and f.Mxl, are not well suited to the requirements of the moths durinK this lengthy period, whereas trees and bmhlmgs offer shelter, and often nourishment also. Since th-re are very few trees on the prairies, tiie moths assemble rapidlv amund buildings and Btraw piles. This holds true also for Nociua clande»fina, whieh has a similar ile-history. Of all places chosen by the moths for congregation, those in which In.th buildings and flowering nlants arc present seem to Im' the most favoured. The light trap, to which we liave already referred, was hung on a jwrch over which ^\ "i?"""'* "^ elematis. This, liesides adding to the shelter afforded by the building, offennl a large supply of nectar and moisture which were sought ■o eagerly by the moths that they could be seen feeding upon it at all hours of the dav. Though a light will not attract the moths of this species from a great dist- ance. It will draw them readily from 15 or 20 feet, and our trap thus recorded the varying abundance of moths at the creeper, and around buildings A similar trap hung outside u small building, which was destitute of vegetation captured on an average 10 males and 12 females of this species per night while the former trap was taking 142 males and 147 females ikt night. Lantern trarw placed in the field during July and August, both at Lethbridge and ut Welling, failed to catch any of the moths, though at the same time they were swarming around lights near and in buildings. ENTRANCE INTO HOV8E8. E' t>ry morning the majority of the moths leave the flowers, etc., whore thev have ....en feeding during the night, and seek out small crevices in which to shelter from the daylight. AInny hide in foliage or in straw piles, while others creep under roof shingles, in cracks around doors or windows, and in chinks between weather-boards. In most of the cases observed, where moths were present m houses m such numbers that they constituted a pest, they had gained admission mainly under the shingles. When these are slightly warped or shrunken tliey offer innumerable small crevices into which the moths creep far enough to be protected from the daylight. Where there is a possibility of working their way through into the building, by however (1 vious a course, many of them will do so. In one house at Lethbridge, which had every door and wmdow screened we took as many as 700 moths a night from a light trap hung m the attic, heedless to say, the attio was not plastered MATURATION OF THE OVARIES. From July 10 to the middle of September a number of female moths were j^issected each week. At the beginning of the flight there was very little fat bccty present in the abdomens, and the ovaries were alwavs undeveloped Bv the end of July the fat body in most moths had increased considerably. The ovaries were developing very slowly, though at this tim.? the individual ova could be seen with a dissecting microscope. The fat body reached its maximum 17 ahumJani-.' l.y nlMiut tho mid«n,. „f AufuM. u. whiih tini.- the ovarirn In-khii to «l.-v.l»p morr rapUlly. till by Aupwt HI, diwH^ud -petimro. revi-alinl .>«h whuh wire almost v< uplfti'lv di'vi'lJip^'d. "* In 1915 the ma, rity •/captive- motliM did not lay iimm until i\w i-nd of JJi'I)t..inlH.r or hi' iHummng of t k-toln-r. By thin tini.. thr moth- had diMapin-and fmm th.' liRhtx artmml huildmRM, the lant cHptiirf iN-inR mad<> on Senti-mlH-r IN. An ••xammation of a ■umm.T-fallow field on s,.pt..mlH»r 29 li'-ulti'Il in the diwovpry of M.vi.ral vpr>- mueh ruhlHMl f.-maloH of thix ^\Hf\i'», hidins und.-r cUhIh. Although wp were unHueeewnful in our attempts to fimi laid egKH at thii* time w,. found that m earh raw the alwlomen wan half filled with mat «• euM whieh imlieated that a numln-r had \wn already laid. Flarlier in the year' when the motliH weri' at the height of their flight aroun.l huilding-, we" had examinefl the -ame field with.)Ut finding an many mothn an we di<| ,m thix .M-.aHioii whirh wa« oyer a week t we had taken our .nM moth m» the light trap. OVIPOHITION AND KwM. DATE or OVIPOHITION. In Alberta the eggs of thin moth are laid exthwively in the fall The eiirlieMt date upon whieh we have an artual reeord of ovi|Kwition Ih Augu- 1 30 ThiH reeord was obtained in 1914. In 1915 the first eggs were obt. ' on September 3. The oviposition perioti extends probably for nearly two m..ntl... since the latest date on which we obtained eggs was Octolier 18, and twelve only of our captured '-males ovipo. ite noil they wrrr never Attached to i-Mrh oUier in RroupM uf more than three. Their diiirovery in nature, if in the Moil, [» therefore a ver>- diffirult matter. The Pale Weatem Cutworm (Porotagrotii orthogonia) unciou>)tediy doe* lay ita eopi in the mil, for on three occaniona we have found it* comparatively large egR* in the loone t>arth under rlodn, though on every ovraaion they were Muffiriently near to vegetation to enMure, a* far an poMiiii>le, a nupply of food for the larv* when the>' hatched. . «L ng. •,— Diaamn aitowNig th« aiahtly raptum ii< Anny Cutwnnn niothn la IVM, Tbt raptvrM mad mi*» tMnprnlum ara avfracnl am-kly. (IMgiaal.) RoMikov (1914) found in RuNNia that the mothit of Kuioa tegrlin laid their eggs in the noil or on straw, and not upon green vegetation, whereui* the vfgn of various species of other genera were found upon the vegetation growing m the same fields. Nt'MBER or EGOa LAID BY AN INDIVIbl'AL MOTH. The largest numl>or uf eggs that we have ubtuineil from a Mingle moth in captivity is 1,100. Though the average wan conHidorahly under this figure, others laid ovi>r a thousand, and it is probahle that in nature the a ,rtT!t|ce would H * *•$) i 9 If n at «w* -«— « ■rum > J / r\ *M / / Y" am / 1 I 1 1 1 I 1 vl •• / 1 > N^ / ; / 1 \ _^ =£ 1 / ^ \ ^:^ pil Kig. 7.— Uiugrain ahuwinit tlir nightly cupturt' of Army Cutworm motha in 1915. The ruptures an>er 28 to 29 wa.'^ placed 10 out-of-«l«M>rii,* ami wan half huriiHl in thr mtil. Thr rt *i« tMipm to hatrh on OrtolMT 29, an«l Ih**)' hmi nil hatrhrtl within four dayH. Nl'MIIRII or HRIMIDH. Our (. MHTVationn Hhuw that th<* moth ii« itiniili>*linNMiiHl in AllMTta, though a tpniii'ncy to vittivat*' Rivett the impn*«Mion, in wmit* y«*un<, that thf>rf> an* two (iintinrt ItrmxlH. Th** Nummpr of HM4 wuh i>xr<>|itiontilly hot in AllH>rta. Our trap n*('oni<*(l flinhtM that year, the Hrnt biMtinR till thr i*nnpt<>nilH-r 12 (tin. m the trmneraturr curve on thi> chart it will lie Mi>n that then* wai« the IpaHt activity aurin| tlu> protracttni hot »pi'\\ in late July an«l AuruM. In 1915, the fliRht wan more rontinuoUH (Hk. 7), though the tem|iorary diminution durinR AuRUHt rorreHpondit fairly clom>ly with the nm> in teni|M>raturt> recorded durinR that month. IxN'al diHturbanceM, Nuch aa wind or rain, rauMii variationM in nightly capture)*, and the chartM do not xhow an plainly a<« we could wiHh the evident relation uf the fliRht of thin moth tp temperature. We iinagine that the two diittinrt fliRhtM of mothn recordeii by (iillette (1004) in Colorado renulte activate. He deticribe« the fin«t flight, which extended from April 16 to July 1(), an lN>ing more abundant than the later flight from Septemm-r 13 to Octolnr 12, of which occasional upecimenM only were itei-n. From the adulti* of the lirrtn, and the following obxervationrt will, we think, throw tutme light on the matter. Towards the end of Julv a numlH>r of captured female K. auxiliarin moths were placed in separate pill Imixch, and were fed on dilute molasses. These l>elongcd to our first flight, and at the time of capture no female moths contained developed ova. During OctolKT three of (hese laid eggs. The eggs were sterile, but they were laid after the last moths of the lecond flight hid been taken at lights, and at the same time as r^oths capturcil during this MM-ond flight wero laying eggs also. Cooley (1908) considered it improbable that thi.i species is double-bn sided in Montana. The only occasion upon which we have oliserveanlele» laetirepa Anhm. 8 times natural niic. '( >riKinal. ) held by stray silks to the mass of cocoons, though it usually lives long enough to crawl away, and it may re-enter the soil. The number of cocoons from one larva varied from three to forty-two, and averaged about thirty-five. The adults hatch about three weeks after the cocoons are made. Meteorus sp. — Probably undescribed— (fig. 10) parasitized 8 per cent of the larvffi. The host does not come above the soil when it is mature, but ma\ form a normal cell, though generally it wanders aimlessly in the soil till the contained larvse bore through the skin and spin up. Their emergence does not Fir. 10. — Mt'teorun ftp., pniljultly un(Irsr the clods by day, and are surrounded with the green vegetation among v/h-ch they lay their eggs. In a large tract of fallow land examin-^l during September, we turned up many more moths when moving clods on such parts as bore w<«eds than we did upon the clean areas. It is essential, therefore, that summer-fallow be kept clean — absolutely clean — from the middle of August until after the end of September. In this way only can summer-fallow be rendered unattractive for egg laying to the moths of the Army Cutworm, as well as to the moths of other cutworms. It is advisable, also, that the surface be worked up as finely as is compati- ble with good farming practices in order that it may offer as" little shelter as possible to the moths. Gillette (1904) states that the moths lay their eggs freely on the prairie. This is true, apparently, in Alberta also, for we have found the larva; far out in unbroken tracts of prairie. They do less harm there than they would on grain fields, and if fallow land is made less attractive to the moths, more of them will lay their eggs on the prairie instead of on cultivated land. REMEDIAL ML AnlRES. On account of the migratory habits of these larvae, no unprotected fields are absolutely safe from attack in years when the larvae are sufficiently numerous to be moving across the county in search of food. At such times they may arrive in swarms upon fields where every precaution h.s been taken to prevent them from breeding. When army cutworms are abundant, therefore, everyone must keep a sharp lookout for them, and take steps to deal with them immedi- ately if they appear on his farm. POISONED BAITS. The Army Cutworm can be controlled in a similar manner to other cutworms by the judicious use of poisoned baits. These can be applied broadcast to attacked fields, but it is advisable so to use them only when the larva> are present in large number-! in a crop which is well above the ground. For such a use we have obtained the best results by 24 the employment of a mixtmt- consisting of: shorts, 50 pounds; molasses, 1 Kal'on; water, li^ Ralldiis; and Paris green, 1 pound. The shorts and Paris green are mixed while dry. The molasses is then dissolved in the water and the solution is added slowly to the shorts mixture which 18 stirred constantly with the hands in order that any lumps which form may be broken up. The mixture is spread broadcast at the rate of 20 pounds of the shorts to the acre, and by preference should hv applied as late in the afternoon as is con- venient. Where the soil is wet the shorts may be replaced fairly satisfactorily with bran, or half bran and half shorts, but wherever possible the shorts should be used. On perfectly dry land bran is almost useless. The reason for this is that bran under prairie conditions in southern Alberta, appears to have very little attraction for cutworms when it is dry, even though it be flavoured with molasses Shorts, when similarly flavoured, however, are almost as attractive when drv as they are while moist. When bran is used the water should be increased to B gallons to overv .'lO pounds. • When obtainabk-, cheap crude beet molassej should be used, .such as that which 18 made by local sugar factories. This i.s more attractive to cutworms than cane molasses, and is incomparably cheaper. TRAP FURROWS. Broadcasting is an expensive means of checking cutworm devastation and on account of the migratory habits of the species we are considering, tht> benefit derived from it may be temporary. Wherever possible, therefore, we would advise that farmers utilize tr. i w.i m which to trap and kill the Army Cutworm. In our description of the life-history of this pest, we stated that the iarvte are seen first soon after the frost is out of the ground. At this time farmers are beginning to prepare their seed-beds. They may find that an enormous number of cutworms are present in, and on, tlic soil of the fields they intend to SOW. • c P"'"J''5P<''"ience is that it is safe to proceed, and to sow the crop on such an infested field, provided that it is deare.l of all growth, and that efficient furrows are made around, and in some cases, through it. Such furrows, when made and poisoned in the manner described below, prevent practically all fn-sh incursions of larvae, and will in a short time capture most of those already in the field. We have already shown that the general movement of larvje is north and west, and that even when allowance is made for temporary variation the mijjra- tion IS, on the whole, in one direction. In the early spring the period intervening between the time when the pre- ■ paration of the seed-bed is begun and the time when the crop first appears above ttie ground is from one to two weeks. We have thus at least a week in which *'\*[?, ^"vantage of the migratory habits of these larvm. When the land is freed from green growth there is no food left for the Iarya> and they migrate at maximum speed, sooner or later to enter one of the trap furrows prepared for them. If, on the other hand, the spring cultivation has not killed or buried all green growth, migration will be much retarded, and the crop may be up before the larvie have been destroyed. In this event, expensive broadcasting of poisoned bait alone will ensure the cron against serious damage It IS essential, therefore, that an infested field be thoroughly cleaned before the crop is sown. Construction of trav furrows.— Vtiually the soil is very drv during the seeding period in southern Alberta, and for this reason it is very 'difficult, and often impo.ssible, to construct a vertical-sided trench of the type usually advocated for holding back an invading srtny of thi pest, or the Army-worm. In wet seasons, however, such a trench would be practical. The plough with which the furrow for such a trench is made must be provided with a coulter. The earth is thrown toward the advancing larvte, so that the furrow is vortical on the side which is to be protected (fig. 12). Such a furrow must be trimmed with a spade upon itj vertical side, so that this may he suffieientiv smooth to prevent the larvte from climbing up it. MlftMTWM. m > TO at PnoTccr CO tilt. 12.— UiiiKruni of viTtical-sidfHl (urniw. (Orijiinai.i Such a furrow cannot be made successfully when the soil is loose and dry. and in any case the subsequent trimming up with a spade calls for more labour than is usually available, on account of the length of the trenches farmers may have to construct. Under such conditions a dusty-sided furrow will be found to be more effective, and is considerably cheaper in construction (fig. 13.) DIKCCTION or Field TOi£ PRCTECTE O Fig. 13. — DiatcniM of dusty-.sided furrow. lOriKinal. Thi« i.< made as follows: Turn a,-: deep a furrow as possible with a walking plough, throwing the eaith towards the field to be protected. This furrow should be sufficiently deep so that the distance from the crest of the ridge to the bottom of the furrow is at least a foot. If this is not obtained with ploughing once, the plough should be run through the furrow again in the same direction as before. Now drag a heavy log down the furrow. The man who is in charge of the horses should stand on the back end of the log to weight it down. This operation will crush all of the large clods, and leave a smfwth, dmtv, sloping side to the furrow (fig. 14). Usually the soil is sufficiently mjist to crumble most easily directly after the furrow has beeu ploughed, while if the log is not drawn down it till the clods have thoroughly dried out, it will be difficult to crush them sufficiently with one operation. 26 The army cutworms which attempt to croso 8uch a furrow experience great difficulty in doing so, for the loose particles of earth move under them, and offer no foothold whatever. No form of trench, however, except one calling for expensive hand lalwur, is effective as a permanent mechanical barrier against the migration of a large number of cutworms. Such a trench, of which a description is given by Gibson (1914) in connection with Army-wurm control, is not often practicable upon large western farms on account of the labour for which it calls. Fig. 14.— Pri'paring a duaty-nided furrow. (Original.) Poisoned bait in furrows.— To make a trap furrow effective it is lecesiiary, therefore, to treat it with a poisoned bait which will kill the larvse entering it. Several mixtures have been recommended for this and for similar purpcwes. We have given most of them careful and repeated trials under varying conditions, and as a result of these numerous experiments we can strongly recommend any of the following mixtures : — 1. Poisoned shorts. — The mixture which we tlescribed for use when broad- casting bait is the one which can be most readily prepared by farmers. The ingredients are: shorts, 50 pounds; molasses, 1 gallon; water, Ij gallons; and Paris green, 1 pound. These should be mixed in the manner described on page 24. Thia bait should be applied at the rate of 10 pounds of shorts to 60 or 70 rods of trench. The cost of materials used in this bait, when crude molasses is used, i.s about $1.20 per mile. When shorts are not available in sufficient quantities they can be replaced with, or mixed with, bran. As before stated, bran is distinctly inferior to shorts, especially in a dry season. 2. Poisoned vegetation. — In several of the localities attacked there were pivtches of stinkweed {Thlaspi arvense) which, on ar(:>unt of its being a winter annual, makes a large and rapid growth early in the spring. Cutworms are particularly fond of this weed, and it can be used to advantage to replace the shorts and molasses as a carrier for Paris green in bait. It is, moreover, a noxious weed, which should be hand pulled in any case. The labour involved in collect- ing this weed is therefore serving a double purpose, and is chargeable to the requirements of good farming more than to the expense of controlling army cutworms. 37 Stinkweed bait w prepared at) follows: Weigh out 50 poundM of the freshly pulled weed, and place it in a heap on the floor of a barn or, if the day is calm, on dry hard ground. Sprinkle with sufficient water to moisten it thoroughly. Now dust in 1 pound of Paris green, turning the vegetation over ronstantly with a fork till the poison is evenly distributed throughout the heap. The bait is now ready for application to the furrow, along the bottom of which the plants should be scattered, 6 to 9 inches apart, so that 10 pounds will cover up to 50 or 60 rods (flg. 13). Fig. 15.— Applying poisoned stinkweed to a dusty-sided furrow. (Original.) The cost of the bait, exclusive of labour, is about 35 cents per mile. It is advantageous to apply the bait late in the afternoon, sinco its attractive- ness depends mainly upon the freshness of the stinkweed. This bait proved to be as effective as poisoned shorts during the first two days after application, but it was not eaten to any extent when quite dry. When stinkweed is not available it can be replaced with other vegetatijn ■^on which the larvae will feed readily. We have used alfalfa with considerable success, and as a bait it is almost as good as stinkweed, though it i* a little less retentive of its moisture. Since, however, no benefit is derived as a direct result from pulling alfalfa, the labour involved makes this a somewhat expensive bait when it is used to replace a noxious weed such as stinkweed. The now growth at this season is not sufficiently advanced to allow of its being cut with a mower. In some cases it may be more convenient to spray vegetation intended for bait, before pulling. For this purpose a mixture of about 1 pound of Paris green to 30 gallons of water should be used, in order that the bait may be heavily coated with poison. Some farmers are unable to obtain either shorts or green vegetation, x'or such we would recommend one of the two following baits, though they are distinctly inferior to the mixtures we have already described: — Fair rnults were obtsined from the use of Affal/a hay sweetened with molMMB; 1} gallons of crude niolaM<>8, diiwolved in r^.j^t an eciual quantity of ^**^fi' '* ""*"* '"*" ^ pounclH of hay, to which as lavrti water i» now added as It will soak up. Two poundH of Paris green are tMn ntirred into the mixture, which should be applied in the evening in as wet a rondition as possible, since it loses its attractiveness when dry. On account of its bulk, 10 pound*, of hay will cover more than 100 rods. A bait can be made also from fresh home droppings, of wh' mnde ar,t sweetened with a gallon of crude molasses and poisoned witl .nd of Pa. is green, but this is a poor substitute. Effect oj cannibalism upon poisoning in furrous. — The quantities of Pariif green recommended in the alwve mixtures are considerably in excess of the actual amounts necessary to kill the individual larva which feed at all extensively upon the bait. The reason for this is that larvs feeding upon such heavily poisoned bait are killed quicklv and very few of them leave the furrow. We have stated already that larvaj feed readily upon each other, especially upon dead specimens. No exception is made with poisoneu larvae, and subse- quent arrivals feed almost as freely upon these as they do upon green vege- tation. These dead larv» thus become, themselves, poisoned bait, and when a large number are migrating, the killed specimens soon cover the bottom of the furrow. We have not tested the length to which this secondary poisoning can be carried, though we find that two larvK are killed readily with a single dead spec'nien which has been poisoned by the bait in a furrow. In any case, the majority of living larva apparently prefer to stay in the furrow and continue to feed upon the dead bodies of those which have been poisoned, till sooner or later they themselves succumb. The post holes we made in treated furrows for estimating the relative value of baits continued to yield up to an 80 per cent mortality a week after the bait had been applied. Comparative value of poisoning in furrows and broadcasting. — When larvte are migrating, we have seen them pass rapidly over dry bait, without appearing to be aware of its pre^nce. In a prepared furrow, however, their progress is impeded, and after one or more unsuccessful attempts to escape, nearly all of them will stop and feed upon the bait with which it keeps them in contact. Experiments were made in which similar amounts of bait were placed upon the open soil and in prepared furrows. An averape of about three times as many dead larva were taken from under the bait in the furrows as from that on the level ground, and in all cases much more of the former bait had been eaten. In order to estimate the value of a dusty sided furrow treated with the short i mixture we have described, we made counts of the dead larvje to the foot of our experimental furrow at Welling eight days after the bait had been applied. The average number of dead larvse was 537 to the foot of trench, which is equiva- lent to nearly 3,000,000 to the mile. At this time there was no sign of the bait left, and since the larvse had been continuously feeding freely on dead specimens the total number already killed must have greatly exceeded this figure. Number and location of furrows.— When a field is considered to be in danger of attack by larv», which are known to be in the vicinity, a single furrow should be made around it. By watching this furrow the farmer will be able to see whether larvoe are attempting to enter his fields. If in the evenings numbers are present in the furrow, it should be treated with bait immediately. If the larvae are migrating on to a field in large numbers it may be advisable to make two parallel furrows, about a rod apart, along the side or sides from which they are entering. The inner one need not be treated unless it is seen to contain many larvaj which have escaped from the first. This should effectively prevent further invasion in large numbers. When a crop ban l)<>i>n auwn, and the larvs arc already numerous in the field, furrow* should l)e piouKheti throufth it in one or imth dirtH'tionx, and poiiHined at once. The dirttance t)etween theiu> furrows varien aorurdinR to the time when the rrop will he up. If it ix not antiripated that the crop will he aliove ground in less than a week, and the field ii« (|uite clean, the furniws ni>ed not lie less than 40 or 60 rods apart. Within a few days most of tiie larve will have entered one of them, and will be poisoned. Before making these furrows, notice the Keneral trend of migration, and arrange them in such a way that they will cut across the line of march. Maintenance of furrow* — After rain it is necessary to draw the log once more down the furrow and so crumble up the surface crust which forms on its sides. This will nec(>Nsitate a second treatment with bait. In any case it is advisable to watch the furrows fr.)m time to time during the migration imtIimI, and to replenish the bait when necessary. It cannot be claimed that this methoer of larva; do comparatively little damage because they do not kill all of the plants which they attack, when there is abundance of food. Thus, at a minimum cost. Army Cutworm damage can Im> reducetl to negli- gible proportions by the use of poisoned bait in conjunction with properly constructed trenches. SPRAYING ALFALFA. We have not known the Aimy Cutworm to kill out alfalfa in Alberta, though when a large number are working across a field of it they seriously retard its growth. In this ca. to move #ithin a few minute* After they were expoMMl rONTWlL MCAIIVRM SOMITIIIES RECOMMENDED BUT VNRVITAELS TO FRAIRIE CONOITIONIt. s»* I'f^^t'^ "* ^ *ofc«--A method of trapping larvc in piMt hole* bored at ntervaU of one or two rodi along prepared furrowH han in-en Uied with huiciw in controlling local outbrcalu of the Army-worm, and ha« liwn oocamonailv recommended to praino farmer... Thi* methtni entails too much expenHivV labour for large fields, for betiidea the labour involved in Iwring the pout holcn the Iarv0 trapped munt l»e dextroyed. Lantern trap$ for the «w/u//«.— Suggestions of various traps for use in th« fields, when the moths of this species are flying, have be<.n made from time to time in the lo-al press and elsewhere. As we have shown in discussing the habits of these moth*, such traps would b<; of so little value that they would certainly nov pay for the expense of running them. Where they might he ot value would be :»ear houses and in other place 4 where the moths swarm before they return to the fieldt* in September «of/inff.-<>ushing the larva> with a heavy roller is sometimes advocated, but this IS rarely practicable under southern Alberta conditions. It is of value only when cutworms are on the surface of hard unbroken soil. On land which ha J been recently worked the majority of larvaj are simply pressed into the loode ■oil, while many of them are subjected to no prejsure at all. A float drawn over such places would be more eff»ctive than a roller, since the action is then more one of grinding than of iimple pressure. ACKNOWLEDGMENTS. Jnv«.S-?f"„''7i"^ *^^/v,''- ^- Anderson, Jr., who started an independent Investigation of this pest at Raymond upon its appearance there. This afTorded parallel data, of which use is made in this bulletin. Mr. F. W. Walsh assirted in the investigation during the latter part of the dPCUiOu* ... '^|?™"f'»°'i* *^''' J°Xf*.*!f*.*'.°" ^''^ laboratory has been under constant obligation to Mr. W. H. Fairfield, Superintendent of the Experimental Farm at ♦k ^-S ^'u'- "*' r™u"y courtesies and suggestions, and without his co-operation the dimculties of the work would have been materially increased. LITERATURE REFERRED TO IN TEXT. 1898 Wilcox, E. V. An Army Cutworm. Montana Agric. Exp. Sta. Bull. 17. 1903 Fletcher, J. Cutworms. Rep. of the Ent. and Bot., Aun. Rep. of Exp Farms, Canada. 1904 Gillette, C. P. Cutworms. Rep. of the Ento. Agric. Exp. Sta. of Col Agric. College, Bull. 94. 1905 Johnson, S. A. Cutworms. Agric. Exp. Sta. of Col. Agric. College, Bull. 1908 Evans, J. D. Rep. of Ent. Soc. of Ontario. SI 1908 Cooli>y, R. A. An Army Cutwomi, Ath Ann. Ri>p. of thf rtUle Rnt. of Montana, Bull. 71. 1010 (Vmlpv, R, A. The Army Cutworm, Mont. Afric- ('"H. Kxp. Hta. Clrr. 4. 1914 Ruiw'!:'jv. Orrupiefl fallow lanm. of Bur. Knt. of th<> Mr. Com. of thf CVnt. Btl. of l^mi Atlmin. and Agrte. P«>troKraii x No. 7. 1015 Coolev, R. A. Control of thr Armv Cutworm, Mont. Aftrir. Coll. Kxp. Hta. Circolar 47. lOtA GilMon, A. The Army-worm. I)om. of Canada, Rnt. Br. Bull. 0.