Hs 
 
 I Hi 
 
 hifertjf if the lioiid Slates Scvernmscl 
 
 ClRCULAH No. 105 
 
 United States Ik'ii.irtni^Mjf^toitilt 
 
 BUREAU OF HNT 
 
 L. O HOWAHI). Kntomologist a 
 
 III i: ROSE si. I <;s. 
 
 r.v r. ii. < 'hi 1 1 1 mm \. 
 In Chargt of Truck Crop <tmi Special //;>..' In mitigations. 
 
 lioses grown in gardens in the United States are attacked by three 
 species of sawflies which live, in their larval stages, on the foliage, 
 skeletonizing the leaves or cutting out holes of variable size and 
 greatly disfiguring the plants. The larva?, popularl} know n as " i 
 slogs," " slugworms," and "roseworms," have been classified as the 
 American rose >\\\n\ the bristly roseworm, and the coiled or curled 
 roseworm, respectively. For the sake of uniformity they may all be 
 called rose slugs. The first of these, ;i- ii- common name indicates, 
 i- native t<> America; the other two are evidently accidental intro 
 ductions from Europe, ;i- they are now common in I >< >t 1 1 hemispheres. 
 \ with 1 1 1 « »- 1 other sawflies," they are found more abundantly in the 
 North, but are quite troublesome as far southward ;i> Maryland and 
 Kansas. They practically confine their depredations t<> the flower 
 
 ; >lcn. ;in«l roses are the only plants thai are seriously damaged l>v 
 them. Injury i- due entirely t<> the larva?, and the three species, each 
 representing a distinct genus, differ considerably in appearance in all 
 stages, as also in their life history and manner of work. 
 
 THE AMERICAN ROSE SLUG. 
 rf< him uiii 1 08a I tarr. < ' 
 
 The American rose slug was firsl identified as ;i pest about the year 
 1831, when it * 1 i « I damage in gardens at Cambridge, Mass. At that 
 time the species was somewhat restricted to that locality, but later, 
 according to Harris, who observed and studied it- habits, it grad- 
 ually spread in that vicinity and by 1840 it hud become so great a 
 nuisance that :i premium of $100 was offered for the most successful 
 method of destroying it. 
 
 " Hymeuopterous Insects of the family TeolkmHuldse 
 * Synonyms : Uonostcgia rosa ■•;:•] Sclandnia rosa" 
 Bepon Ins. <>f M..-<s. inj. to Veget., 1841, i 
 5411B Clr. L06 06 
 
 52$. 
 
DESCRIPTIVE. 
 
 The sawfly which produces the American rose slug is a four-winged 
 bee-like insed (fig. 1. a) of a deep shining black color, with tran- 
 luccnt smoky wings having dark-brown veins and a brown spot near 
 die middle of the edge of the forewings. The wing expanse of the 
 female is about two-fifths of an inch and the length of the bod \ 
 fully one-fifth of an inch. The male is a little smaller. 
 
 The larva or slug (A. figs. 1. 2) when full grown is about one-third 
 of an inch long and sluglike, with the thoracic joints enlarged. The 
 
 Fig. 1. — American rose slug (Endelomyia rosw) : n, Adult sawfly; b. mature larva; c, 
 work of larvae on rose leaf; <l, section of rose leaf, Showing location of egg near upper 
 margin ; e, egg in situ on bit of rose leaf, o, '». e, Much enlarged : o, loss enlarged ; d, 
 about natural size. ( Original, i 
 
 body is soft and delicate, but not gelatinous and slimy, as is the case 
 with some sawfly larvae — for example, the pear slug. The color is 
 green above and yellowish on the lower surface. The head (fig. 2, c) 
 is small, oval, and yellowish, and has a black spot on each side, 
 inclosing the eye. 
 
 DISTRIBUTION. 
 
 The assertion has been made by Riley " that this sawfly undoubtedly 
 originated in New T England, where it fed upon wild rose. With the 
 lapse of years, if we assume this statement to be correct, it has been 
 disseminated by commerce into neighboring States and through the 
 
 ° American Entomologist. Vol. Ill, 1880, p. 115. 
 
 [Cir. 105] 
 
3 
 
 importation <>f rose bushes rrom eastern nurserie to '■ tern gardens. 
 Owing to the sluggish habits of the female, its distribution l>\ flight 
 has undoubtedly be6n rorj slow. Ii occurrence in Nev York, Sen 
 
 p, Ohio, Illinois, Michigan, and Missouri ha been known for a 
 number of year . and it undoubtedly occupies intervening States, 
 
 In 1904 we received reports of injuries bj il in Pennsylvania, New 
 York, Maryland, and Kansas; In that year it also appeared :it Char 
 
 ville, Va., and the following May reached the District of Colum 
 bia, where it has been quite abundant since. In 1908 il was reported 
 injurious :ii ( !incinna1 i. < )li i< >. 
 
 < ... 
 
 
 W 
 
 I 
 
 I 
 
 CL 
 
 ' >v 
 
 Pifl -. American rose ^in_- [Entleloi ,. r larva al 
 
 work on upper . lower lai under surface; '.. larva, 
 
 rtew, enlarged; e, head of iirv.i. more enlarged I Original i 
 
 Ml l HISTORY. 
 
 The parent sawflies issue from the earth at varying time- from 
 about the Lsl of April, or earlier in the District of Columbia, to the 
 third week in Maj . or, according to Harris, until the middle of June 
 in Massachusetts, beginning ;it about the time when the roses first 
 unfold their leaves and continuing until they are in full leaf. During 
 this period pairing takes place and eggs are deposited. The females 
 are particularly sluggish in the cool of morning and are not often -ecu 
 in flight, resting during the greater part of the day on the leaves. 
 When disturbed they draw up their legs and fall to the ground The 
 males, however, are quite lively, flying from one rose hush to another 
 
 and hovering around their less active partners. 
 
 [Clr 
 
The female in depositing her eggs turns a little in one side, 
 unsheaths her delicate saw-like ovipositor, and thrusts it between 
 the two cuticles of a leaf, depositing a single vgg in each incision. An 
 egg is shown about natural size at <I. figure 1. and much enlarged at <. 
 The egg i- of circular outline, much flattened, and measures about 
 one-twentieth of an inch in diameter. Hatching begins in from 
 ten days to two week- after the eggs are deposited. 
 
 The larva' or slugs are to be found at work as early as the 1st of 
 .May in the District of Columbia, but their appearance in number- is 
 seldom noticed until the second or third week of that month. Obser- 
 vations conducted at Washington, 1). C., show that the periods men- 
 tioned are subject to considerable variation. In L905 the first 
 sawflies of the new generation appeared June 2. Owing to the 
 irregularity of appearance of the parent " flies.*' larvae of the first 
 generation may be found at work for a period of live or six weeks. 
 Feeding takes place chiefly at night, and always on the upper surface 
 of the leaves, the lower surface, ribs, and midribs remaining as a 
 skeleton ( fig. 1, c). The leaves are practically always skeletonized, 
 not eaten into as in the case of the other two rose slugs, except when 
 the larva' are nearly grown. During the daytime the larva usually 
 rest- concealed on the under surface of a leaf ( fig. 2, a). 
 
 Sometimes the larva' are so abundant that not a leaf on a bush is 
 spared, and the foliage look- as though it had been scorched by fire, 
 and eventually drops off. The larva? are stated to be between two 
 and three weeks in attaining their growth. They cast their skins 
 several times, leaving them fastened to the leaves. After the last 
 molting they lose their greenish hue and become opaque yellowish. 
 They then descend into the earth to a depth of an inch or more, and 
 each constructs for final transformation a somewhat fragile oval cell 
 or cocoon coated with particles of earth. Here the insect remains as 
 larva until the following spring, when it transforms to pupa shortly 
 before issuance in May. 
 
 The species i- single-brooded, in which respect it resembles many 
 other species of sawflies." 
 
 REMEDIES. 
 
 This rose slug and the others which will be discussed are quite 
 easily controlled by several different methods. 
 
 Sprinkling with water. — A strong stream of water directed upon 
 the plants from different sides by an ordinary garden hose or large 
 
 " It is evident from Harris's account (I. c.) that in ascribing two generations 
 
 to this rose slug he must also have had the bristly rose slug under observation. 
 Miss M. E. Murtfeldt writes on tins head that she has disproved Harris's state- 
 ment " by repeated rearing of the insect under close observation." (41st Annual 
 Kept. State Hort. Soc. Missouri, 18'JS, p. 2SS.) 
 [CIr. 105] 
 
 
syringe, if applied every daj or two, will soon rid rosebushes of the 
 pest, rhia is ;ii the Bame time an excellent remedy for rose aphidee 
 or plant lice. The insects are dislodged, fall to the ground, and are 
 unable t" return to reinfesl the bushes. This remedy was tested 
 practically by Dr. L. O. Howard mam years ago. 
 
 Pari Where it is possible t<> apply them without danger 
 
 of poisoning human beings or disfiguring the plants for ornament, 
 different poisonous preparations are useful. Of these, Paris green, 
 cither dry or in solution, arsenate of lead, and white hellebore are 
 • I remedies. Paris green is best used as a Bpray in the proportion 
 of an ounce iii ;i gallon of water. Applied dry, it is mixed with •_'" 
 
 part- of Hour or similar diluent and puffed on the plant- by mean- of 
 a powder bellows or insufflator. For use in large gardens, however, the 
 poison is employed at the rate of 1 pound to from 75 to 125 gallons 
 of water, lime being added in about the same proportion as Paris 
 green to prevent scorching. For properly mixing and applying this 
 insecticide a -prayer of good quality should be used. Sprinkling 
 with n watering pot or with a whisk broom will n<»t answer the pur 
 po-e and is, moreover, dangerous to tender foliage. The Pari- green 
 i- first mixed with n small quantity of water into a fine paste before 
 the bulk of water i- added and should be churned in the sprayer or 
 force pump until thoroughly blended. The resulting mixture, being 
 a mechanical one. i- not con-taut and the arsenical sinks to the bo( 
 torn. The solution should therefore he constantly stirred while 
 being applied in order that an even application may he made. In 
 applying an arsenical spray an effort should he made to reach all of 
 the lea\e-. which may he accomplished by spraying from two sides. 
 Two or three applications will suffice for the spring generation of 
 rose slugs. Scheele's green and some other arsenicals can he used 
 instead of Paris green. 
 
 Arsenate of lead. A -till more valuable insecticide for such insects 
 a- rose slugs and other leaf feeders i- arsenate of lead, hut it- use i- 
 open to the objection that it di-color- tin- leafage, leaving a white 
 deposit, which is not. however, permanent. It i- applied in practi 
 (•ally the same manner a- Pari- green and i- a less poisonous arsenical, 
 and, being -old in paste form, i- used at a considerably greater 
 strength about 1 pound combined with 15 to 25 gallons of water or 
 Bordeaux mixture. Being adhesive, it adhere- more firmly to the 
 leafage and is much less likely to produce scorching. 
 
 Hellebore. Hellebore is used at the rate of l ounce to from 2 to :'. 
 gallons of water, and kills by contact a- well a- by it- poisonous effects 
 
 ■Additional information in regard to the preparation and use ..f arsenate ••( 
 lead ami other Insecticides is given in Farmers' Bulletin 127, wblcb may be 
 had gratis .»n application to the r. s. Department of Agriculture. 
 [Clr tor.] 
 
when oaten by the insect. It is less poisonous to man than an arsen- 
 ical, but not so effective to leaf-feeding larvae. It may also be applied 
 dry mixed with about double its weight, or more, of powdered plaster 
 or cheap flour. 
 
 When not in use the receptacles containing poisons should be 
 plainly labeled " Poison ! " and placed on a high shelf or in a locker 
 out of the reach of children. Properly applied, there is no danger, 
 in using an arsenical on ornamental plants, of poisoning human 
 beings, or domestic animals other than rabbits or similar pets. 
 
 Soaps and other washes. — Oily soaps, such as fish-oil or whale-oil 
 soap, and other soaps, and tobacco water will kill these insects, but 
 their use is open to the objection that if applied just before or at 
 blossoming they are apt to injure the petals of delicate flowers, and 
 whale-oil and tobacco also leave an unpleasant odor. A neutral 
 soap, such as castile or that used by physicians and surgeons, leaves 
 no odor. 
 
 Dry powders. — Fine, sifted road dust, where this can be readily 
 procured, is also of value thrown upon the plants, preferably by 
 means of a powder bellows, as it closes the breathing pores of the 
 larva? and thus kills them. Finely powdered lime, and buhach (Per- 
 sian insect powder, or pyrethrum) are also effective. 
 
 Hand picking. — If rose slugs are picked oil' by hand upon their 
 earliest appearance this will greatly reduce their numbers for the 
 following year. In the adult or " fly " stage these insects may be 
 easily captured by hand on cool mornings. Hand picking may be 
 tedious, but it is effective. 
 
 Fall cultivating. — If other means that have been specified have not 
 been utilized for the suppression of the slugs, many individuals may 
 be destroyed by frequent cultivation of the soil between the rose 
 plants during the late summer and autumn. This has the effect of 
 breaking up their pupal cells and otherwise disturbing the insects so 
 as to interfere with proper hibernation. 
 
 THE BRISTLY ROSE SLUG. 
 
 (Cladius pectimcornis Fourcr.) 
 
 The bristly rose slug, called also the spiny rose slug, is the principal 
 enemy of the rose in and near the District of Columbia, not excepting 
 the rose-chafer. It is believed to have been brought in from Europe 
 some time prior to 1833, since it was mentioned by Harris in his 
 catalogue of Massachusetts insects of that date. In the early 
 seventies it was reported from Connecticut and in after years it made 
 its way westward and southward, doing more or less injury where- 
 ever established. Since 1880 it has done much mischief in Wash- 
 [Clr. 105] 
 
ington, I >. ('. In 1886 it was reported from Lafayette, [nd. In 
 i W as ob erved to be injurious a( St Charles, Mo. Soon after 
 wards it was recognized as a pe < it St. Louis, where ii attracted 
 considerable nttention. 
 
 hi S( RIPTION \ M> I » i — I RIB! I los. 
 
 The adult of this species (fig. 3, a) differs considerably from thai 
 of the American rose slug, as will be readily seen by a comparison of 
 the illustrations of the two forms. It is ;i larger insed and u mem 
 
 ber of a differenl genus. The wing »x | »:i 1 1-.- is ;il t one-half of an 
 
 inch for ili«' female; a little shorter for the male. The ground color 
 i- black. The antenna are rather stoul and acutely pointed, and in 
 
 Fio. :! Brlet - {Cladtut pectinicornU) a, Adult female; '-. antenna <>( male; 
 
 .-. larva: d, head of same; t, female pupa: /. n VII enlarged. (Reengrayed after 
 
 Riley, except •/. original. 
 
 the male the proximal joints, or those nearesl the head, are pectinate 
 or comb-toothed (fig. 3, &), which has given rise to the specific name 
 /-. ctinu ornis. 
 
 The egg (fig. I. a) is white, flattened, rounded, stoutest at the 
 anterior end, and more pointed at the opposite end. It measures about 
 
 3 mm. in length. 
 
 The larva or slug, shown in figure '■"<. c, and figure 1, <. </. varies 
 from yellowish to glaucous green, and the whole surface is quite 
 bristly, especially at the sides, a character from which this larva de- 
 rive- its common name and which will distinguish it from the other 
 two that feed upon the rose. The length when full grown is a little 
 [Clr. 106] 
 
more than three-fifths of an inch and the diameter is between one- 
 tenth and two-tenths of an inch. 
 
 The pupa (fig. 3, e) is grayish green, the thorax and end of the 
 body are slightly yellowish, and the antennae, wing-sheaths, and !• 
 are while with a slighl greenish tinge.'' 
 
 The distribution includes the States of Massachusetts, Connecticut, 
 New York, New Jersey, Pennsylvania, Maryland, the District of 
 Columbia, Indiana. Illinois, and Missouri. 
 
 It is generally distributed on the continent of Europe and occurs 
 also in England and Scotland. 
 
 Fig. 4.— Bristly rose slug (Cladiua pectinicornis) ; <i, Egg; h. portion of leaf showing 
 eggs in situ and work of young larva- : c, <i, lateral and dorsal aspects of midci' 
 ment of newly batched larva : c, larval claw ; /, rose leaf showing nature of defoliation. 
 All except/ enlarged. (Reengraved after Riley.) 
 
 LIFE HISTORY. 
 
 The bristly rose slug differs considerably from the preceding in its 
 life economy. Its appearance at Washington. D. C., and at St. Louis, 
 Mo., has been observed from the latter days of April to the third 
 week of May, beginning about the time that the first rose leave- are 
 put forth. Its eggs are inserted in the upper surface of the petiole 
 of the leaf and are deposited in rows of three or more together. 
 
 The slug in its earliest stage skeletonizes the leaves, leaving whitish 
 blotches and small holes (fig. 4. f), but with increased growth it eats 
 large, irregular holes in the leaf (fig. 4. &), devouring the entire sub- 
 
 s More detailed descriptions <>f the stages are furnished in C. V. Riley's 
 article, Insect Life, Vol. V, pp. 6-11, which includes accounts of the other t\v<> 
 species here treated. 
 [Clr. lor»] 
 
stance, and frequentl) leaving nothing but the stronger ribs. While 
 feeding, the slug rests in concealment on the lower »ui*facc of :i leaf, 
 and does nol feed < >> i the upper surface, as does the American rose 
 slug. Upon attaining full growth ii does not, like the latter, aban 
 ■ Ion (lie plan! upon which ii has fed until the final generation, [ndi 
 cations are thai there ma) be three and, in -nun- in its 
 
 southernmost range, perhaps four generations produced each year, 
 larva occurring as earl) as the 1st of Ma) and as late as the Isi 
 lit' November. In northern Europe two generations are recognized." 
 The larvae of the earlier generation spin their cocoons ( fiir. 3, />. 
 which are composed parti) of silk and parti) of a glutinous sub 
 stance, upon the lower surface of the leaves, or mi twigs or near by 
 objects, usually surrounding them w ith an irregular fringe. The lasl 
 or autumn generation forms it- cocoons among fallen leaves and other 
 rubbish about the base of the rose bushes. 
 
 The egg period in late April and early in May has been observed 
 in the District of Columbia to last for from seven to ten days, and 
 the young larva? begin feeding in tin' lir-t and second weeks of May. 
 
 I .mi \ re grow rapidly, and cocoons have been Ion mi by the middle of 
 May. The pupal peri ml observed was fifteen da) . so thai the second 
 brood of flies may appear before the end of May. This second g 
 eration begins work about the second week in June, l>ut during July 
 there is a comparative cessation, presumably between the second and 
 third broods of worms, when fresh growth is little affected. 
 
 Mr. (I. Paul-. St. Louis Altenheim, St. Louis, Mo., wrote in re{ 
 to observations conducted by him on this species at St. Louis in 1904. 
 The sawfly continued depositing eggs up to September 17. October 
 
 II he placed larvas in a jar: three transformed to pupa' October 17. 
 l!'. and •_' I and issued March 30 to April 10 of the following year. 
 One larva pupated October 16 and issued March •_'_'. having passed 
 about five months in the pupal stage. This shows considerable varia- 
 tion in tlu' time of issuing indoor-, and would probably be duplicated 
 to a certain extent in the open. April •_"•> he observed the sawfl) 
 depositing eggs on the have-. 
 
 , \ vrt RAl ENEMIES. 
 
 No natural enemies of tin- rose -Inn- appear to have been recog- 
 nized in America, hut in Europe it i- preyed upon by two paras 
 Acrotomus luciduliu Grav. and Mesochorus cimbicu Uat/. 
 
 ■Various European authors have written en this species. One <>f fin- most 
 accessible general articles is thai by M. s. <\ Snellen van Vollenboven, trai 
 
 lated from i he Dutch by J. W. May and nuulisbed iu The Entomologist, Vol. 
 vill. is?."., pp. 26 - ■• 
 [Clr. lor.] 
 
10 
 
 REMEDIES. 
 
 The same remedies advised against the American rose slug are em- 
 ployed against the presenl species, with the exception of fall cultiva- 
 tion, which is practically useless when applied to it, owing to the 
 fact that the cocoons are formed upon the plants on the surface of 
 the ground and not buried in the earth as with the preceding specif-. 
 Since there are more than one generation of this slug, sprinkling 
 with water and spraying with poisons must be repeated several tin 
 in order to produce the desired results: in short, as often as the 
 insects reappear upon the plants, from April to October, according to 
 locality. 
 
 THE COILED ROSE SLUG. 
 
 (Emphytua cpnetus L.°) 
 
 The third of the rose slugs under consideration, the coiled rose 
 slug, is a comparatively recent importation. As with the two pre- 
 ceding species, it first attracted attention near Boston, Mass., but 
 not until the year 1887.'' It is probable, however, as in the case of 
 most European insects introduced into this country, that its importa- 
 tion was accomplished at a considerably earlier date. Reasoning 
 from analogy, this insect might have been brought from the mother 
 country on potted roses ten or twenty years earlier than the date 
 specified, as that length of time is sometimes necessary for a foreign 
 insect to become permanently established so as to attract attention 
 by its injuries. 
 
 DESCRIPTION AM) DISTRIBUTION. 
 
 From the two preceding species this insect may be readily sepa- 
 rated on account of its larger size in the adult stage (fig. •*>. a). It has 
 nearly transparent wings, and a wide band which crosses its shining 
 black abdomen near the middle. The body is comparatively slender, 
 and the head longer than in the other two species. The wing expanse 
 is about five-eighths of an inch and the length of the body about three- 
 eighths of an inch. 
 
 The larva when mature is about three-fourths of an inch long and 
 differs notably from the other two species here considered in being 
 perfectly smooth. It is cylindrical and tapers very slightly toward 
 the posterior extremity. The color is metallic green above, orna- 
 mented with small white dots, and the lower surface, including the 
 legs, is grayish white. The head (fig. 5, c) is yellowish orange, with 
 a dark brownish-black stripe down the middle. The eyes are black. 
 
 ° Emphytus cinctipes Nort. is recognized ;is a synonym. 
 ».T. G. Jack. Garden and Forest, Mar. 26, 1890, pp. 151-152. 
 [CIr. 10r>] 
 
II 
 
 The tii -i thoracic segment is ' • 1 1 1«- and the las! two are gi The 
 
 larva habitually rests in the coiled or curled position shown in 
 figure •">, 6, one that is never assumed by either of the other rose slugs, 
 
 and it is from this habil thai it der English m 
 
 In addition to Boston, it has been authentically reported from 
 Jamaica Plain, Roxbury, and Nev Bedford, Mass.; portions of 
 Mimic; Allegheny, I'a.: Nev York, and Canada. In the Eastern 
 Hemisphere this species ranges over the major portion of Europe, 
 extending int<> Siberia. 
 
 NATURAL HISTORY. 
 
 The coiled rose slug is credited with being double-brooded, and as 
 it extends it- range southward it will probably produce a third gen- 
 eration, since we know of the appearance of the " worm " from May 
 
 i"i.; 5 Colled rose Blug {Bmphytua cinctua) : a, Adull fei Full grown larva; ■ . 
 
 head of same; ''. work on plant : t, <. young Ian ; >/. '>. 
 
 enlarged; c, more enlarged. (Reengraved aftpr Riley.) 
 
 to October. Eggs are deposited singly on the underside of the 
 leave- to the observed number of from three t<> -even. This slug 
 differs from the other-- in devouring the entire substance of a leaf. 
 feeding along the edges with it- bodj roiled beneath it. and when al 
 resl remaining curled in a ball on the lower surface (see 1 i ir. 5, e). 
 Upon reaching maturity the slug deserts the leave- and bores into 
 the pith of the stems of dead rose bushes or other available plants, 
 and here the pupal state is passed, the fall generation hibernating to 
 emerge the following May. At Boston, Ma—, the adults have also 
 been observed in duly, this indicating the first new generation. 
 
 \ more technical description by I>r. II. <;. Dyar is given in the Canadian 
 
 Entomologist, VoL XXVI, p. 160. 
 
 [Cir. 105] 
 
UNIVERSITY OF FLORinA 
 
 12 ■illffillllll 
 
 3 1262 09216 5298 
 
 NATURAL KM. M iks. 
 
 A parasitic enemy of this species was reared by the writer from 
 larva- received from Allegheny, Pa., in 1904. It issued October 20, 
 and proved to he a tachina fly, Tachina rustiea Fall. 
 
 In Europe an ichneumon fly, Cryptus emphytorum Boie., is para- 
 sitic upon this sawllv. 
 
 REMEDIES. 
 
 The remedies are the same as for the American rose slug, subject, 
 however, to the same changes as for the bristly rose slug. 
 
 Approved : 
 
 James Wilson, 
 
 Secretary of Agriculture. 
 
 Washington, I). C, August .',. 1908. 
 
 [Cir. lor, J 
 
 o