16 J. E NTOMOI.. Soc. BHIT COI.UM lllA 74 (1977). DF: c. 31. 1977

PARASITES OF THE CASEBEARER, LARICELLA (: ). IN THE WEST KOOTENAY AREA, BRITISH COLUMBIA 1

G ORDON E. MILLE R' AND THELM A FINLAYSON'

ABSTRACT The parasite complex of t he larch casebearer. Coleophora laricel/a (Hbn.). was investigated in the Kootenay area of British Columbia in 1973 and 1974. Forty-one species of hymenopterous parasites were obtained fr om rearings of almost 153 .000 fin al-in star host larvae and pupae. In 1973 and 1974 . 31 and 24 species. respectively. were reared. with 14 co mmon to both years. Twenty-nine of these. in 24 genera. were confirmed as larch casebearer parasites by individual rearings and by reports in the li terature. No parasites were obtained from eggs. needle-mining larvae. or third-instar case-bearing larvae. The highest total percentage parasitism was 17.7% in 1973 and 24.5% in 19 74. both at Rossland. In Collection II t he Dicla docerus spp. complex comprised 46.0% of the total parasitism in 1973. and 63.8% of the tota l in 1974: it was the most abundant at four of the eight collecting sites in 1973 and 13 of t he 14 sites in 1974. Spilochalcis alhifmlls (Walsh) comprised 32.8% and 23.5% of the total parasitism in the years 1973 and 1974 respec tively : it was most abundant at three collection sites in 1973 and at two in 1974. Mesopolo/Jus sp. constituted 4. 9% of t he total in 1973 and 9.9% in 1974. Larch case bearer densities in the first co llection in 1973 were highest at Fruitvale and Shoreacres wit h 150 and 130 cases per 100 fascicles respectively: in 1974. t he highest host densit ies in t he first collection were at Kootenay Bay and Fruitvale with 48 and 41 cases per 100 fascicles respectively. IV!'RODe CTroN Yahk. In 1974 these eig ht were again investi­ The larch casebearer. Co leo phora laricel/a gated plus the following additional six sites: (Hbn.) (Lepidoptera: Coleophoridael. a Cranbrook. J ohnstone Creek Park. Kootenay E uropean species introduced into western Bay. Roosville. Rykerts and Winlaw (Fig. II. North America. is currently a target of Collection I on May 14- 15. 1974. consisted biological control efforts. Releases of exotic mainly of fin al-in star larvae and Collection I I parasites have been in progress for about 17 on June 12- 13. mai nly of pupae. years (Denton 1972: Morris and Monts 19 72: Ten t rees were sampled in each collection at Ryan and Denton 1973: Ryan el al. 1975. 19771. 1. 5 - 3. 0 m (5-10 ft. I and at 6. 1 - 7.6 m (20-25 ft.) Turnbull and Chant (19611 argued that the Five primary branches were taken from the full ecology of a pest being considered for a circumference of each tree at each heig ht. biological control programme should be studied Mass-rearing was done in 30. 5x61.0x30.5 em in t he area of proposed release prior to t he (lx2x 1 ft.) cardboard boxes in which t he tops introduction of natural enemies. To determine had been replaced by 0.2 mm mesh. Individual the identities of parasites and degree of paras i­ rearin g of larvae and pupae collected at t ism of C. laricel/a in British Columbia. surveys Cascade. Ro ssland. Sheep 's Creek and Shore­ were carried out in 1973 and 1974. Resul ts of acres in 1974 was done in '/2 dram vials to t he 1973 survey were reported by M iller and which fr esh larch needles were supplied as Finlayson (19741 . required by t he feeding larvae. METHODS Eggs were collected both years from 10 Procedures in 1974 were similar to those t rees at each site and mass-reared in petri used in t he 1973 survey and were described by dishes. Early larval instars were collected at Miller and Finlayson. Samples were taken in Rossland and Shoreacres in August and 1973 at eight sites: Anarchist Summit. Arrow October. 1973. These were mass- reared in Creek. Cascade (=Christina Lake l. Fruitvale. approximately t he same way as t he later Rossland. Sheep's Creek. Shoreacres. and instars. RESU LTS lBascd on a thC' si ~ s uhmitt ed h.\' t he s pnior <.Iu t. hor in part ia l A total of 134.5 11 C. laricel/a were mass­ fulfill ment. o f a n M .Sl'. d!'grl'C' . reared: 102.947 in 1973 and 31,564 in 1974: and 18,300 were reared individ ua ll y in 1974.

-' (;radU3t.e ~ tud (' nt and Professor, respt'ctivel,\', Simon F'ra s ~'r In 1974 there were 20.168 casehearers in U ni\'ersit y . Burnah,\', fl.C. V;)/\ l SI) Coll ection I and 11 .396 in Collection II. whereas J. E NTm IO L. Soc. S HIT. COI. U\I FlI r\ 74 ( 1977). DI·:c. 3 1. 1977 17

Scale m iles o 30

~ Range o f Larix ~ occidentillis

~ Rangeof ~ Coleophora la ricella

~ - - - CO LLECTIO N SITES

ANAf '~ Cf II ST SU MMIT 8 WINLAW JOHN STONE CREEK PARK 9 KOOT E NAY BAY CASCADE 10 ARROW CREEK R OSSLAND 1 1 RYKERTS 5 FHUIT V ALE 12 YA HK 6 SHEEP'S CR E EK 13 CR ANBROOK SHOR EAC RES 14 ROOSV I L LE

Pig. I. Di s trihu t ion o f ('oll'ophora larinlla in I1ri tish Columbia in 1972 and location of till' coll ection s ites in 197:, and 1974. ( Adapted frolll H. F. Shepherd and D. A. 110ss. "Pr'oble m analysis : larch casebc'arf' r in /3 .C." U npublis hed J nLernal l1 epOf'I BC-:\? P ac. For . l1 es. Cent .. Victoria. I1. C. 197:3). I II J. ENTmWL. SOc. BHIT. COI.lJMIl IA 74 (1 977 ). DE c 3 1. 1977 t he comparable coll ections in 1973 amounted to In 19 74, a total of ] ,91l9 specimens of 24 40,695 and 62,242. As more samples were t aken species of hy menopterous parasites and hyper­ in 1974 t han in ]973, t he figures indicate a con­ parasites were reared as compared with 4,459 sid erable reduction in populations over tbe specimens of 3 1 specie s in 1973 (Miller and range of t hi s s pecies in British Columbia Finlayson 1974). The total number of species between the two years. obtained in t he two years was 41, with 14 common to both. TallIe I. Confirmed parasites from mass-rearings of Coll'ophora lariel'lI a in Rrit ish Columbia in 1973 and 1974

Abunda nce 1974 May 8-9 May 23-25 May 14-1 5 June 12-1 3 No. No. No. No. No. No. No. No. Hy menopterous Parasites Obtained Sites" Obtained Sites" Obta ined Sites" Obtained Sitesh

Braconidae Rracon pygmal' us Prov. ','," 32 5 273 8 9 5 6 4 I ch neumonidae Campopl('x rufip<,s Prov. " 2 1 ()iadcgma s p.' ,' 3 2 1 1 Gl' lis ('n('lIus (Say)', ' , " 2 2 2 2 Gl' li s s p. " " , 9 4 3 2 Itopl(>('(is Vl'sca Townes' 1 I 2 I I'ris(omerus sp. " ' 2 1 4 4 4 3 Scam bus dl'l'lIruS Walley ' 10 2 4 2 2 1 E ulophidae !\ehryso('han'lIa s p. '. ' 30 3 7 2 3 Chrysol' haris laricincll at, (Rat7.. )', ' 5 2 Cirrospilus pic(us (Nees )3 I I ()ieiado('erus spp. (2) " " ' 325 8 1.4 80 8 693 14 669 14 Elach('r(us pro(l'o('ratis (How.) ' Euderus cushmani ICrawford) ' 2 I Eulophus sp. '* 2 2 I Tl'trastichus dolosus (Ca han) , 9 2 Tdrastichus ('(,us Wlkr. " ' 14 2 5 Zagrammosoma ampricanum Gir. ' 10 2 E ncyrtidae Cnpidosoma sp. " Pteromalidae Ca(olanus a£'lll'oviridis IG ir. ) ' ." 2 I Habrol'ytu5 phyl'idis Asbm. , , I 5 2 Ml'sopolobus sp. " ' ]5 2 15 8 6 III 9 104 9 Chalcididae Spilochaleis albifrons (Walsh) ', ' , " 1.054 6 247 7 E ury tomidae Eu ryt uma s p. ,, * Diapriidae Tell'nomus spp . 13) ' * 6 2 Trissolcus sp. 3* 10 2 -- -- a-out of 8 b-out of 14 I confirmed by individual rearin gs in this study 2 confirmed by Bousfield a nd Lood 11973 ) 3 con firmed by Webb 11953) * confirmed to genus only. J. E NTO\lOL. Soc. BRIT. COL UMBIA 74 (1977), D EC. 3 1, 1977 19

Table 2. Relative a bunda nce of the confirmed Colt'ophora laricl'lIa parasite species obtained from mass·rearings of C. laricclla in British Columbia in 1973 and 1974 (in per cent)

1973 19 74 Species May 8·9 May 23·25 May 14 · 15 June 12·1 3 ---- Dicladoeerus s pp. 86.7 46.0 83.2 63.8 Spilochaleis a lbifrons 32.8 23 .5 Rraeon pygmaeus 8.5 8.5 0.6 Mcsopulobus sp. 4.9 13.3 99 Tetrastichus ee us 4.4 0.1 Ot her (no. of species) 4.8 (3) 3.3 (19) 3.5 (7) 2. 1 (12) ------

Some of the parasites that emerged from loch alcis aibi[rons (Walsh) were previously mass-reared samples could have come from recorded by Andrews and Geis tlinger (1 969) . hosts other tha n C. larieeLla that were These workers also obtained Bracoll sp. which accidentally included in the collections. A mass· may well have been B. pYf{maeLls Prov; reared parasite was considered to have come AmbiymerLlS sp. which probably is the same as from C. larieel/a only if it had been obtained the M es(}poiobll s sp. found in this study; and a from t he individual rearings in this work, or species reported as DieladocerllS lOes / woudii had been verified previously (Bousfield a nd Weslw. which may be either of the two new Lood 1973; Den ton 1972; Sloan 1965 ; Webb species found in this study, D. nearc/iells 1953 ). Yosh. or D. paci[i clI s Yosh. (Yoshimoto 1976). Twenty·nine s pecies have been con firmed as Two s pecies not taken in the s tudy but which parasites of C. larieella (Table I). The 12 have been reported previously as parasites of species not considered to be casebearer para· C. iaricella in British Columbia are S camblls sites are; Aphidills sp. (Aphidiidae ); Aeruly /a /rallsg resslIs (Holmg.) and S ceptro/heiys sp. , H ypuso /er sp. Ochneumonidae) ; deiolle (Wlkr.) (Andrews and Geistlinger 1969). Apros/oee/ll s spp. (2) , Diglyphlls sp., A lt houg h many parasite species were ob· M eliltobia sp. (Eulophidae ); Thysanll s s p. tained, only a few predominated , with (Thysanidae ); Cyrtogaster vulgaris Wlkr. Dicladocerus spp. and S. aibi[rol1s being by far (Pteromalidae ); AphanogmLl s sp. (Cera phroni· t he most a bundant (Table 2). The most a bun· dae); and A e1is ta sp. (Diapriidae). dant species were also the most widespread Most of the confirmed species represent new (Table 1) . Dicla ciocerLl s spp. and M esopoioblls host records for British Columbia. Gelis sp. increased in relative abundance in 1974 ten"l/lIs (Say), S eambLl s deeorus Wly., T etra sti­ when compared with 1973, while the other c/lLl s eells Wlkr. [=xanthops (Ratz.) I a nd Spi· s pecies tha t were relatively abundant in 1973

Tahle :1. Summary of confirmed parasites from mass-rearings of Coleophora laric ella collected at 14 locations in British Columbia on May 14· 15, 1974 .

I Pa rasit ism C. laricella IDiciadoccrus spp. Mesopolohus s p. Other Total No. of Cases/ 100 No. 0/. No. No. No. No. of 0/. Location Cases Fascicles I Emerged 0 Emerged % Reared % Reared Taxa 0

Anarchist Summit 95 1.2 1 1.1 1 1 1.1 Arrow Creek 2, 126 29 .8 36 1.7 9 0.4 3 0. 1 48 2 2.3 Cascade 1,488 17.7 61 4.1 9 0.6 8 0.5 78 7 5.2 Cranbrook 53 0.6 3 5.7 3 1 5. 7 Fruitvale 2,774 40.8 86 3.1 11 0.4 11 0.4 108 5 3.9 J ohnstone Creek Park 169 8.5 2 1. 2 2 1 1. 2 Kootenay Bay 4,275 47.8 9 0.2 4 0.1 5 0.1 18 2 0.4 Roosville 61 0.7 3 4.9 3 1 4.9 Rossla nd 832 8 .0 54 6.5 3 0.4 9 1.1 66 4 7.9 Rykerts 4,6 19 27.5 162 3.5 27 0.6 3 0. 1 192 2 4.2 Sheep 's Creek 1.873 19.7 12 1 6.5 3 1 1. 7 19 1.0 171 5 9.1 Shoreacres 1.604 25 .4 150 9.4 18 1.2 13 0. 8 181 6 11. 3 Winlaw 94 1.2 4 4.3 l.l 5 2 5.3 Ya hk 105 0.8 1 1.0 1.0 2 1 1.9 ""o

Tabl e 4. S um mary of confirmed par asites from mass ·rearings of Coleophora laricella collected at 14 locat io ns in British Columbia on Ju ne 12·13, 1974

I Paras it ism I I Spilnchalc is '- I C. laricplla Dicladocl'rus s pp. I Mcsopolnbus sp. a lbifrnns Ot her Tota l trl ~ I No. of Cases / lOo l No. 0/, No. % No. 0/, No. No. No. % 3 Locati on I Cases Fasc icles . E merged 0 Eme rged Eme rged 0 Reared % Reared of T axa ::: r- o

Anar chis t Su -' ~4----o.~-I -5- ~m~ - - 5.3 1 6 2 6.4 l.l [fJ 11 0.7 Arrow Cr eek 1. 546 IS. 1 I 97 6.3 12 O.S 8 0.5 128 3 8.3 o,..., Cascade 1,199 10.5 53 4.4 9 0.8 60 5.0 5 0.4 127 13 10.6 ttl Cra nbrook 3S 0.4 2 5.3 2 I 5.3 Frui tva le 1.6 15 26.1 71 4.4 11 0.7 12 0.7 5 0.3 98 6 6.1 '" J ohnsto ne Creek P ar k 115 5.0 4 3.5 4 1 3.5 () o Koote nay Bay 2,024 36.0 62 3.1 3 0.1 65 2 3.2 C:: Roosv ille 56 0.7 1 I.S I I I 1.8 ::: Ross land 147 3.9 23 15.6 2 1.4 6 4. 1 5 3.4 36 2 24.5 0: Ry ker ts 1.720 IS. 1 123 7.2 24 1. 4 14 O.S » 6 0.3 167 3 9.7 -...J Sheep 's Creek 1.001 9.4 97 9.7 IS l.S 19 1.9 17 1.7 151 6 15.1 .. Sho reacres 1. 724 15. 1 124 7.2 27 1. 6 124 7.2 12 0.7 287 13 16.6 <.!:> Winlaw 75 O.S 5 6.7 I \.3 1 8.0 -...J 6 -...J Yahk 42 0.3 2 4.S 1 2.4 3 1 7. 1 :- U :'l (') W .....

<.!:> -...J -...J J . E :'-ITOMO I.. Soc. BKIT. CO I.lHIBL\ 74 (1 977 ). DF.c 3 1, 1977 2 1

decreased , relati vely. In 1974. Dic/adocerus was found again in 1974, Ryan et al. (1 974 ) spp. were t he most abundant at all locations in give possible expla nations for the presence the fir st collec tion (Table 3) and at 13 in t he of these species. second (Table 4). In 1973, j)irlac/oceru s spp. A uathis pl1mila (Rat z.) (Braconidae) is were the most abundant at six of t he eig ht conspicuous by its a bsence in t his survey. It locations in t he first collection and at fi ve in t he was released against C. laricella in British second collec tion : B . pygmael/ s was t he most Columbia in 1969 and has since become esta b­ a bunda nt at t wo in the fir st collec tion a nd one li shed (Morris and Monts 1972 ). One of t he in the second : and S. albifrolls was the most release sites was less than one mile from t. he a bundant a t two in the second (M iller and Arrow Creek location in t hi s study. Finlayson 1974). The increase in parasitism between t he two Greater parasitism, in terms of both number collections in both 1973 and 1974 indicates t hat of taxa and percentage parasit ism, occurred adult parasites are active during this period in t he second collection tha n in the fir st in both and/ or that C. laricella reaches a more suscep­ 1973 (Miller and Finlayson ) and 1974 (Tables 1, t ible stage, Sweep-net collections of adults of 3,4). B. p ygmaeus, J. vesca, Diclaclocerl1 s spp. and The greatest casebea rer densities per 100 MesofJolobus sp. during t he first 1974 collection fascicles in 1974 we re at Kootenay Bay and confirmed their presence in the fie ld during t hi s Fruit vale where t here we re, respectively, 47. 8 period. The increase in parasitism by S. albi­ and 40.8 in t he fir st co llection and 36.0 and 26. 1 li"olls between collections was probably co rrela­ in the second (Tables 3, 4). The greatest total ted wi t h the increase in host pupal populations percentage parasitism of 24. 5% occurred at bet ween collections, as pupae are t houg ht to be Rossland where host density was 3.9 case­ the stage attacked by t hi s species (l3 ous fi eld bearers per 100 fascicles. Percentages of para­ and Lood 1971) . Similar increases in parasitism sitism at the vario us locations were not rela ted of C. laricella and other coleophorids during t he to host densities, as was also t he case in 1973 spring- feeding perio d have been reported (Miller and Fi nlayson 1974 ). (Beacher 1947 : Bous fi eld and Lood 197 1: Achrvsoc:harelill sp. was the only gregarious Doner (934) . parasite species indicated by indivi dual Mortali ty of C. laric:ella caused by t he na t ive rearings. The mean number of adults produced parasites may be limited by t he number of from four cases was 3.25. Bous fi eld and Lood alternate hosts available to t he parasites in t he ( 19 71 ) also found a very low in cidence of absence of sui table instars of C. laricella as g regariousness. However, t hey found three t hese, or reia ted species, are known to have species, A chrvsocharella sih'ia Gir ., T. ceus more t han one generation per year I Clausen and M es()polobus sp., t hat occasiona lly pro­ 1962: Dowden 1941: Jasch 1973 1 and not all of duced more t han one adult per case. t hem can be spent on C. laricella. S. aibif/'Oll s is No parasites emerged from mass-rea rings more dependent on alternate hosts t han other of 2, 427 eggs, 19,279 needl emining larvae, or species as very few females (2.5% of the spec ies 6,890 fa ll -co llected, casebearing, third-in star total in 1973 and 0.0% in 1974 ) emerged fr om lar vae, C. laricella in t his study . DI SCLSS IO\ A positive trend was noted bet ween total The parasite co mplex and incidence of para­ percentage parasitism and t he lotal nu mber of si tism on C'. Ill ric"lla in British Colum bia were lepidopteran and sawfly larvae (whi ch mayor compara ble to those in other areas of Nort h may not be alternate hosts of t he parasites America I fl o us fi eld and Lood 197 1. 1973: taken ) at fi ve of t he sites. In eastern Ca nada Denton 1972: Sloan 1965: \Vebb 19531. The the introduced species C. laricillellae, is much parasite co mplex also resembles the complexes more effect ive against C. laricella in t he in t he Alps region of E urope (J asch 1973), presence of A. p umila or in t he presence of alt hough more major spec ies, in terms of rela­ a lternate hosts due to improved synchroni­ tive a bundance and constanc~ ' , occurred in t he zation (Quednau 1970 ). The lack of alternate A Ip s . There was a low in cidence of three species hosts has been suggested as a limiting factor of of parasites in needle-mining lar vae and case­ parasitism in other coleophorids (Beacher bearing, t hird-instar larvae in t he Alps, 1947: Doner 1934,19361. whereas no paras ites we re taken frolll t hese Spec ies of exot ic parasites t ha t have been stages in Bri t ish Colum bia. There are no recently released, or t hat are co ntemplated fo r reports of parasites t hat emerge from ( '. lari­ release, against C. la ricella in western Nort h cella eggs. A merica are taxonomically rela ted to the native Miller and Fin layson (1974) reported two species reared in t hi s study. They also are non­ European species that had been released specific and non- synchronized with C. laricella again st C laricelill in eastern Nort h America (with t he excep tion of A. pI/mila) and have a in the 1930's: ( 'hr\,socharis laricillellae (Ratz.) minor role in reducing larch casebearer popula­ a nd Cirrospill/s pic/us (Nees). C. laricil1(,lIa e t ions in Europe (Jasch 19 731. For t hese 22 J. ENTOMOI.. Soc. BHIT. COLUMRIA 74 (1977), D F.c. 31, 1977

reasons, the probability that they will be effec­ Agriculture. Ottawa. Ont., for identifying the tive biological control agents in western North parasites. The work was supported by National America is questionable. Research Council Grant No. A4657 and in ACKNOWLEDGMENTS 1973 by Contract OSP3-0228 from t he Pacific We t hank Drs. J . R. Barron, L. Masner, Forest Research Centre. Canadian Forestry W. R. M. Mason. C. M. Yoshimoto, and Messrs. Service, Department of the Environment, H . E. Bisdee a nd M. Ivanochko, Entomology Victoria, B.C., for both of which we express our Research Institute. Canada Department of appreciation. References Andrews. R. J . and N. J. Geistlinger. 1969. Parasites of the larch casebearer , Co lcophora laricclla (Hbn.I, in British Co lumbia (Lepidoptera: Co leophoridae l. J. entomol. Soc. Brit. Columb. 66: 50- 5 1. Beacher. J. H. 194 7. Studies of pistol case-bearer parasites. Ann. ent. Soc. Am. 40: 530-544 . Bousfield , W. E. and R. C. Lood. 197 1. Impact of parasites on the larch case bearer in the Northern Region 1970. U.S.D.A. For. Servo Rept. 71-4, Northern Region, Missoul a, Mont. Bous field, W. E. and R. C. Lood. 1973. Parasites of t he larch casebearer in Montana. Idaho, and Washington. Environ. E nt. 2: 212-213. Clausen. C. P. 1962. Entomophagous . Ha fner Publ. Co. , New York. Denton, R. E. 1972. Establishment of Aga this pumila (Ratz.1 for control of larch casebearer, and notes on native parasitism and predation in Idaho. U.S.D.A. For. Servo Res. Note I NT-1 64, Intermt. For. and Range Exp. S t n. Doner. M. H. 1934. Observations on t he biology of Micrubracon pyg maeus (Prov.I, an important parasite of Co leophora pruniclla Cl. Ann. ent. Soc. Am. 27: 435-442. Doner. M. H. 1936. Hymenopterous parasites of Co leophora pruniella CL., and parasites recorded from other species of Coleophura. Ann. ent. Soc. Am. 29: 224 -24 4. Dowden. P. B. 1941. Parasites of the birch leaf-mining sawfl y (Phyllotoma nt'morata). U.S. D.A. Tech. Bull . 757. Jasch , A. 1973. Populationsdynamik und Parasitenkomplex der Lioirch enminiermotte, Coleophora laricella Hbn .. im natiirlichen Verbreitungsgebiet der E uropa ischen Uirche, Mill. Z. a ngew. Ent. 7:1: 1-42. Miller. G. E. and T. Finlayson. 1974. Native parasites of the larch case bearer. Colcophora laricella (Lepidoptera: Coleophoridael. in t he west Kootenay area of British Columbia. J . entomol. Soc. Brit. Columb. 71: 14-2 1. Morris, E. and J. Monts. 1972. Larch casehcarer infestations in Nelson Forest District. 1972. Can. For. Serv .. Forest & Disease Surv. Pest Rept .. Pacific Forest Research Centre, Vi ctoria. B.C. Quednau, F. W. 1970. Competition and cooperation between C. laricint'llae and A. pumila on larch casebearer in Quebec. Can. Ent . 102: 602-612. Ryan. R. B .. W. E. Bousfi eld . R. E. Denton. R. L. J ohnsev. L. F . Pettinger and R. F. Schmitz. 1975. Additional releases of larch casebearer parasites for biological control in the western Un ited States. V.S.D.A . For. Servo Res. Note PNW-242. Ryan , R. B .. W. E. Bousfield , C. W. Johanningmeier. G. B. Parsons, R. F. Schmitz and L. J. Theroux. 1977. Releases of recently imported larch case bearer parasites for biological control in t he western Vnited States. including relocations of Agathis pumil a. V.S.D.A. For. Servo Res. Note P NW-290. Ryan, H. B .. W . E. Bous fi eld , G. E. Miller and T . Finlayson. 1974. Presence of Chrysocharis lari­ cinellae, a parasite of the larch casebearer, in t he Pacific Northwest. J. econ. Ent. 67: 805. Ryan, R. R. and R. E. Denton. 1973. 1ni t ial releases of Chrysocharis laricinell ae and Dicladocerus Wl'stwoodii for biological control of the larch casebearer in the western United States. V.S.D.A. For Servo Res. Note PNW-200. Sloan, N. F. 1965 . Biotic factors affectin g populations of the larch casebearer Colcophora laricc lla Hbn. in Wisconsin. Ph.D. Thesis, Univ. of Wisconsin, Madison. Wisc. Turnbull, A. L. and D. A. Chant. 1961. The practice and theory of biological control of in sects in Canada. Can. J . Zool. :19 : 697-753. Webb. F. E. 1953. An ecological study of t he larch casebearer. Col eophora Iaricclla Hbn. (Lepidop­ tera: Coleophoridae l. Ph.D. Thesis. Univ. of Mi chigan. Ann Arbor, Mi ch. Yoshimoto, C. M. 1976. Revision of the genus Dicladoccrus (Eulophidae : Chalcidoidea l of America north of Mexico . with particular reference to species attacking larch casebearer (Lepidop­ tera: Co leophoridae l. Can. E nt . lOR: 1173- 1206.