The Lancaster Farmer 



Prof. S. S. RATHVON, Editor. 



LANCASTER, PA., OCTOBER. 1875. 



Vol. VIL Mo. 10. 



THE ARMY WORM. 

 J.fiirit It itt titi i/iti n ctii . 



On page l:U, Scptomher iiumlun- of The 

 Faumkh, in an extract fioni the Gnrrcl Coun- 

 (i/(M(l.) f/((2i"((f,lK'aiie(l "Destnictive Worms, " 

 \ve sugjicstod that said worms were ])rolialily 

 the "Army Worm," addini; tlie scientilic 

 name, to let tlie intellij^iMit ri'ader know ex- 

 actly what we nicant l)y "Army Worm," be- 

 eanse it i>ften occurs, that when almost any 

 worm injurious to vegetation becomes numer- 

 ous, the uninformed, or undiseriniinating, are 

 very apt to designate them "army worms," 

 just as if numbers alone were necessary to de- 

 termine the siHM'ies of an obnoxious subject of 

 the insect world ; although it is very probable 

 that the true army worm had been so called, 

 from the fact that it generally appears in 

 large and destructive armies. It is not jn'oba- 

 ble lliat Vegetation will suffer anything from 

 army worms the present sea.son, but having 

 the illustrations on hand, we have thought it 

 meet to enlighten our readers as to what the 

 anuj' worm really is, as a suliject for future 

 reference. 



The army worm has appeared in Pennsyl- 

 vania at dilVerent periods, and in different 

 places, but we have not hoard of its Jjeing 

 here — at least not in Lancaster county — dur- 

 ing the present year. Fiy. 1 represents the 

 mature larva of tliis insect, and it will be seen 

 that it very closely resembles the common 

 "cut-worm." and to which it is allied. In 

 the absence of a specimen of the larva from 

 which to describe it, we will appropriate a 

 brief description by Prof. Riley, and we 

 think this, with the illustration before them, 

 will enable our readers to recognize this worm 

 when they hapi)en to see one. If they cannot, 

 then the fault must be theirs and not ours. 



"The general color is dingy black, and it is 

 striped longitudinally, as follows : On the 

 back a broad dusky strii)e ; then a narrow 

 black line ; then a narrow wliite line ; then a 

 yellowish stripe ; then a narrow sub-obsolete 

 white line ; then .a dusky stripe ; then a nar- 

 row white line ; then a yellowish stripe ; tlu'ii 

 a sub-obsolete white line ; belly obscure 

 green." This, of course, has reference to the 

 one side, or one-half of the worm. It will be 

 seen that it is composed of a head and twelve 

 segments, or sections. To the first three are 

 attached three pairs of feet called the "pec- 

 toral feet," or legs ; then thia'e are two seg_- 

 ments without any feet ; then there are four, 

 each containing a pair of prehensile feet, or 

 "pro-legs ; '' with these it holds fast wliile it 

 stretches the fore part of the body out in 

 search of Ibod ; then there are two more seg- 

 ments without any feet, and the terminal or 

 anal one has a pair of feet very similar to the 

 other eight. 



The ]iu]ia, or vlirijsalis, is a glossy chestnut 

 or mahogany Ijrown, and resembles the pupo' 

 of cut-worms generally, but not so dark in 

 color as some of them. The apex, or end of 

 the abdomen, is armed with two converging 

 points, or si)ines ; two tine hooks on each side 

 of them. These jiupa- are naked in the earth, 

 in a sort of cavity, but no cocoon around 

 them, and it is by means of these spines and 

 hooks that they work themselves towards the 

 surface of the earth, when the moth is ready 

 to come forth. 



When mature, tile hirv<i is about an inch 

 and a-lialf in length, and the head is .some- 

 what broader than the succ<'eding segments, 

 of a pale gravi.sh yellow color, speckled with 

 brownish. 'I'he juijki is about three-ijuarlers 

 or an inch in length, and aliout the .sanii- in 

 circumferenci' at the thickest part. Fiij. 2 is 

 the inuKjo, or perfect moth, the body of which 

 is robust an(l three-cpiarters of an inch in 

 length ; the expansion of souif specimens be- 

 ing two inches from tip to tip of the wings. 

 Tlu' geni'ral cohu' of the moth is a fawn, or 

 reddish brown, and it has a whitish spot near 

 the centre of the front wings, from whence 

 comes the specific, name luiijiuncta; there are 

 dusky oblicpie lines on the wings. 



This insect 

 belongs to 

 the old limu- 



ly JS'ortllithl, 



or "night- 

 flyer.s," and 

 originaly Ije- 

 longed to the 

 tyiiical genus 

 of that fami- 

 Fi,/. 2. ly. 



The army worm and motli seem to be widely 

 diffused, as varieties of them, or species nearly 

 allied to them, have been found in England", 

 in Brazil, in .lava, in India and in Australia, 

 and no doubt it occurs wherever grass grows. 

 Entomologists are by no means in jierfect 

 agreement as to whether it is single or double 

 brooded; that is, whether it |iroduces one or 

 two broods within the year. ^^ery able 

 authorities, however, maintiiin that it is single 

 brooded. It apjieai-s to have been Very de- 

 structive the present season in Maryland, and 

 that it appeared about the end of "August, if 

 that is really the insect to which the |iara- 

 graph in the Septendier nundier of The 

 'Fakmeu alludes. Prof. Hiley states that in 

 southern ^lissonri it appears in the larva 

 state about the middle of April, and in 

 the northern part about the middle of .May. 

 while in Massachusetts it ajipears in the mid- 

 dle of .Tune, and in Maine in the middle of 

 July. In the State of Pennsylvania we might 

 look for it from the middle of May to the first 

 of .Tune. 



The develomenlal progress of the army 

 worm seems to be from "egg to egg" during 

 the Spring, Summer and Autunui ; that is, the 

 eggs are generally deposited sometime during 

 tlie autumn, on perennial grasses, at or near 

 the base of the plant, where they remain all 

 winter, and are hatched out in tlie spring, 

 from the beginning of May to the beginning 

 or middli! of .July, according to latitude or 

 temperature, except those that winter in the 

 pupa state, of which there are often many. In- 

 deed it is very probable that they are hatched 

 out at dirt'erent jieriods, and the larva aiipear- 

 ing at these different periods in the .same 

 locality, seemingly evinces that there is more 

 than one brood in a season, but this may only 

 be an appearance. Be that as it may. how- 

 ever, after the larva has matured it goes into 

 the ground to be transfornud to the jiiijia. and 

 this accounts for the sudden disa|)i)earence, 

 to the great a.stonishment of tlie farmer 

 .sometimes, who is altogether unable to 

 account for this disappearance, and imagines 

 that it has at least left the premises for 

 " a little season." But when it ajipears 

 again it will not be in the form of a worm 

 but in the form of a moth. When they have 

 Ihiished one field or enclosure, they trav(d in 

 immense numbers to another, and from this 

 circumstance they have received theircommon 

 name "army worm," as previously suggested. 

 They differ very materially in size and color 

 in the different localities where the}' have oc- 

 curred, from the eastern to the western States ; 



sojnneb so indeed, both in the larva, llw ]iu])a 

 and the iiiKKjn, as to seem like<lifrerent species, 

 but no doubt tliey are all the same. This 

 habit of trav(ding from one field to another, 

 has led some of the farmers who have been 

 troubled Willi them to head them off by jdow- 

 ingdeeji furrows across their track, the straight 

 side of the furrow being toward the licdd niiin- 

 fested. The worm then finds it dithenlt or ini- 

 po.ssible to ascend the straight side, and isthus 

 arrested in its progress. Here thev often 

 gather in teiis'of thousands and are destroyed. 

 Some strew dry straw or leaves in these fur- 

 rows and set lliein on tire, and thus destroy the 

 worms. 



It is suggested that the earlierof the worms 

 or the moth breeding IVoin them, deposit their 

 eggs on the grass higher up the stock, and 

 tiiat thus they are cut off and carried to the 

 stack or the liarn, and from thence get into 

 the dung heap, from whence they are carried 

 to the fields. 



They seem to thrive best in moist sea.son.s, 

 or on moi^t lands, if the moisture is not too 

 great. Too much heat and too much moisture 

 are not favorable to theii' health or increase. 



Army worms do not occur in destructive 

 numbers, more than one or two sea.sons in 

 succes.sion. If they sometimes appear for 

 three consecutive seasons, it is (juite ns often 

 that their ajipearance is liniite(l to a single 

 season. This is owing to the fact that there 

 are a nvniiber of [larasites that prey upon 

 them, and these parasites greatly diminish 

 their numbers the second season, and entirely 

 exterminate them the third. 



At least two of these parasites are "Taehina- 

 tlies" — namely, the "Red-tailed Tachina " 

 (E.e<iri.-<ta /(wcaiiiVi, Kirk,) and the " Yellow- 

 tailed Tachina" (ExoriKta ./(f/nV((m?a, Riley,) 

 both iiretty large species, being a third of an 

 inch or more in length, and having tlie'geiieral 

 appearance of the common grey and black llesh 

 flies. And then there are two or three pretty 

 large Ifliiuwiinn flirs conspicuously among 

 which is the army worm ophion (Oiihiim fnirga- 

 tiis. Say). We have on several occasions bred 

 liotli tills insect (or an allied spi'cies) and a 

 species of IVtii/us out of vari<ius Lrpidiqilerout 

 larva, esiiecially the "Fennel worm.s," [I'ajii- 

 /»')) besides two small hlinriimonn, namely : 

 the ^[lf:nl■lwru.1 vitrtux and the Przamarhiui 

 niiniurux of Walsh, and the army wcuin Ich- 

 neumon " (IcIiiKumiin kucatiia, of Dr. Fitch,) 

 and also some others, making seven or eight 

 in number, or even more. " 



It has not only been stated — with what 

 truth we are unable to say— that the army 

 worm has been known to pass through wheat 

 fields and destroying all the chess or cheat 

 growingin them and leaving the wheat intact, 

 but that they have absolutely saved the crop 

 in helds infected with rust, by eating oflf all 

 the infected blades and leaving the ears of 

 wheat free of injury, and that disgusting as 

 they are, they have saved the farmers in a 

 single neighborhood thousands of dollai-s. If 

 this can be substantiated, it will only be an- 

 other illustration of how completely disgui.sed 

 a blessing may lie, or that, under certain cir- 

 cumstances, a blessing may grow out of what 

 we have deemed a curse. But, of course, it 

 would not be wise in farmers to depend much 

 ujion such contingencies, lest they might un- 

 con.sciously "reckon without their host," and 

 find themselves overwhelmed in the end. 

 From what has been ssiid, it will lH\seen that 

 thearmy worm deposits itseggson the grassdur- 

 ing the summer and autumn, and that the eggs 

 remain there all winter; if therefore, such 

 grass is burned off, when it is dry, the 

 eggs will be destroy<-d. and a brood of worms 

 from them will be prvvented the following sea- 

 son, and prevention is always better than cure. 



