Sarai, D. S.

Journal of the Entomological Society of British Columbia

JOUK:"I AL E !,( TO:\[o1.. Soc. BI!IT . r.nr. UilfBLI , VOl .. 6:1 ( 19(;6 ), DEC. 1, 1966 1 9 THE PEAC H TWIG BORER, Anarsia lineatella ZELL. (LEPIDOPTERA: GELECHlIDAE), I~ TH E OKANAGAN AND SIMILKAMEEN VALLEYS OF BRITISH COLUMBIA D . S. SARAI I INTRODUCTION The peach twig borer, Anarsia lineatella Zell ., is reported from Eu-rope, ASia, and North America . It is present in 35 states of the U.S. (Bail-ey, 1948) , in Ontario and British Co-lumbia, where it is often a serious pest of peach and apricot in the Okanagan and Similkameen valleys. Almond, cherry, necta rine, plum and prune are also listed as host plants (Bailey, 1948). The la rva tunnels the buds and terminal twigs and infests the fruit. The present study was in-tended to provide information on which to base more effective timing of insecticide applications. Some growers h ave had diffkulty in con-trolling this pest. METHODS and MATERIALS The seasonal his tory was investi-gated from 15 May to 15 October , 1966 in peach and apricot orchards near Penticton in the Okanagan Valley and Cawston in the Similka meen Val-ley. The presence and activities of different stages were recorded each week and the developmental s tages collected for detailed study. In the laboratory cages small vials of water plugged with absorbent cotton sup-plied water to the moths. The larvae fed satisfactorily on green or ripe peaches and apricots. Green fruit lasted fo r from 10 to 15 days, and the larvae easily re-established in fresh fru it. When mature larvae left the fruit most of them moved to the top of th e cages to pupate in folds of ch eeseclo th ; others pupated in cor-n ers or in folds of paper. Tender shoots were not satisfactory food be-cause they wilted or died within three days. It is not known whether over-wintered larvae, which feed normally on buds and shoots, can also develop on fruit. They were a lready pupating by mid-May. , Summer e mployee , B.C. Dept. of Agriculture, Vernon, in 1966. To study adult flight patterns two U-V ligh t traps were used, one 10 miles south of Penticton , the other five miles east of Cawstoll . The light was on each night from 8:00 p.m . to 6: 00 a.m . The bottle under the light was partly filled with a 70% mixture of ethyl and methyl alcohols, which was emptied and replenished every fourth day . The method was imprac-tical in that it was extremely time consuming to locate the small moths in the great number of trapped in-sects, but it did give some indication of the adult population levels and s upported the field observations. Adults a re difficult to observe in the orchards because they :ue small and their colouration blends into the bark. Adult emergence in orchards was noted by marking pupae and ch ecking these regularly. The cre-master is securely attached so that the empty cases remain after the adult.') h ave emerged. SEASONAL HISTORY The seasonal history was the same in the Okanagan and Similkameen valleys . Fig. 1 shows the seasonal h istory at Penticton in 1966. Over-win te red larvae which had been feed-ing on buds and new shoots, started to pupate by mid-May. A few larvae were still feeding, but most of them were moving downwards to the large limbs and trunks to pupate in cracks, pruning scars, or under loose bark. By 24 May a lmos t all had pupated. The mature larva is about 13 mm long. It spins a loose, grey-white web and pupates beneath it. The pupa is 3 to 4 mm long, brown to dark brown, attached by the cremaster. Moths were first seen on 7 June and the peak of adult population was reached about mid-June. Oviposition began within a few days of emergence of the adult and 20 JOUI{:\,AL E1\TO~IO I.. Sel(". BIUT . C ()!.l:\ IIH .\ , V() I .. 63 (19G6) , DEC. 1, 1966 4i o ~ o OJ C ·c 4i C ~ CV ~ .~ > c_ U"I '-~ Q.~OJcv .3~-oOJ > ~«LUO \ • ft' . ' l • ~ : : ~' • d : it': ( 40. .. 1 0:: LU co :E LU I-0-LU I ~ i I LU Z l ~ 1 J >-« :E Figure I-The seasonal history of the peach twig borer, Anarsia lineatella Zell. in the Penticton area of the O",anagan Valley, B.C., 1966. JOURNAL E N TOMOL S OC. BRIT. CO r. C ~[BlA , \ ' 01.. G3 (1 966) , DEl'. 1, 1966 21 continued for about two weeks. Most few in the second instar were in-of the eggs were laid on the terminal valved. These larvae were not seen to parts of young shoots but some were migrate from bark cells t.o fruit as laid on fruits. Larvae from these r eported in California by Bailey eggs were first seen on 22 June feed- (1948). ing on terminal and side shoots and leaf bases. The n ewly-hatched larva is about 5 mm long, light brown with a black head. Wilted shoots caused by first-instar larvae were not noticea ble since they consisted only of one or two small leaves. But by 6 July they were noticeable because the longer larval tunnels included more leaves. A wilted shoot with a larva s till ins ide was clean, but an abandoned shoot exuded gum. Wilted shoots were few-er and damage to fruit started earlier on apricot than on peach, nossibly be-cause apricot has fewer shoots and softer fruit. Some larvae apparently fed on apricot fruit at once on hatch-ing in late-June, whereas damage to peach fruit did not start until about mid-July. In the hard unripe fruit the tunnels were superficial, and mostly in the stem half . Pupation began about 20 July, in cracks in the bark or curled bark, under loose bark or even on the s ur-face of the fruit. The larvae did not spin a web . Adults emerging from these pupae were first seen on 3 Au-gust, and were in maximum numbers by 10 August. They were easily seen in heavily infested orchards resting on trunks, branches and frui t . They were seen more often on apricot tha n on peach fruits. The eggs were laid on bark and on fruits. Most of the apricots were picked by the end of July so that ob-servations after that time were made on peach fruits. Hatching s tarted by 7 August. Larvae hatched from eggs on fruits made very small entry holes marked by brown frass on the sur-face; larvae hatched from eggs on bark started making overwintering chimneys in crotches of two-to four-year-old branches. They fed on the cambium to hollow out overwintering sites (hibernacula). M 0 s t of the larvae were in the first instar but a Larvae in fruits developed nor-ma lly al though some made chimneys before starting to feed . They pupated from 5 to 12 September, and the emerged adults were seen from 14 to 28 September. These laid eggs mostly on ba rk but also on fruits which were I eft on the trees . Ha tching occurred in the las t week of September . Most of th ese n ewly-hatched larvae made hibernacula . Thus overwintering lar-vae a re from eggs laid by third and second generation moths. A few la rvae were still feeding in fall en fruit at the end of September and h ad developed beyond the sec-ond insta r . None could be found after mid-October, by which time night temperatures had dropped to about 4 cc for a week (40°F) . DISCUSSION Weldon (1914, cited from Duruz, 1923) concluded that the peach twig borer in California had 3. Single, un-even genera tion per year , emerging over a long period. Duruz (1922,1923), Ba iley (1948) and Price & Summers (1961) observed three to four genera-tions . Kin g & Denman (1960) men-tioned a fourth generation in Texas The presence of hibernacula in Au-gus t may have led earlier workers (Treh erne , 1923; Vena bles, 1940; Pro-verbs , 1954) to assume that the Au-gus t hrood wa.s the overwintering gen eration in the Okanagan Valley. It appears that voltinism in this species is controlled not only by tem-pera ture , but also by food; larvae fe edin g on fruit in August developed and completed the third generation, whereas those feedin g on bark built hibernacula. The only parasite observed was a poly- embryonic chalcid, Paralitomas-L x pyralidis (Ashm.), which laid its eggs in the twig borer 's eggs. Peach twig borer larvae from parasitized eggs died at maturity . At this time 22 JO U H-'AI. E"TO ;IIOI.. So(". BIUT. COI.P~II:tA, VOl.. 63 (1966), DI':c, I, 1966 the larvae were full of parasites which could be seen under a micro-scope through the translucent skin of the host. The adult chalcids emerge soon after the peach twig borer moths; oviposition in host and para-site is synchronized, and the parasite also has two or three gellerations per year. From 40 to 65 chalcid adults were seen to emerge from each host. References Bailey, S. F. 1948. The peach twig borer. California Agr. Exp . Sta . Bull. 708. 56p. Duruz, W. P . 1922. Peach twig borer experiments in California. J . Econ . Entomol. 15:395-400. Duruz, W. P. 1923. The peach twig bore r (Anarsia lineatella Zel!.) . California Agr. Exp. Sta. Bull. 355. 57p. King, D. R., and T. E. Denman. 1960. The life history and seasonal occurrence of the peach tWig borer in Texas. J. Econ. Entomol. 53:680-681. Price, D. W ., and F. M. Summers. 1961. Cyclical changes in numbers of moths and larvae of the peach twig borer in California. J . Econ . Entomol. 54:933-936. Proverbs, M. D. 1954. Chemical control of the peach twig borer, Anarsia lineatella Zel!. (Lepidoptera: Gelechiidae), in the Okanagan Valley of British Columbia. Proc. Entomol. Soc. Brit. Columbia . 51 :31-36. Quist, J. A. 1963. Control of peach twig borer. Colorado Agr. Exp. Sta. Progress report 99. Summers, F. M. 1949. Resistance to basic lead arsenate by the peach twig borer with-in a small area in central Ca lifornia. J. Econ . Entomol. 42:22·24. Treherne, R. C. 1923. The peach twig borer (Anarsia lineatella) in British Columbia. Proc. Entumo!. Soc. Brit. Columbia. 17 and 19:176-183. Venables, E. P. 1940. The peach twig borer or peach worm. Canada Dept. of Agl'. Vernon, BC. Mimeo. A RECORD OF Adranes tay lori WICK HAM (COLEOPTERA:PSELAPHIDAE A wind-thrown western red Cedar of 18 inches diameter was found to have a 9-inch dead strip on one side. This was infested with termites and field ants, Lasius sitkaensis Pergande. The wood with the ants was kept in the laboratory and moistened regu-larly. After five months two small and unusual beetles emerged; these were Adranes taylori Wickham 1901, of subfamily Clavigerimae, family Pselaphidae. Adranes is a genus of obligate inquilines, restricted to the nests chiefly of Lasius ants and known only from North America. Eight spe-cies are recorded from the Pacific Northwest (Hatch , M. , 1962, Beetles of the Pacific Northwest, Vol. III). They a re eyeless, with 3-segmented antennae, composed mostly of the very large 3rd segment, and ha-/e vestigial mouth parts. These are the only Clavigerinae in the University collection. G . J. SPENCER, University of British Columbia. 

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The peach twig borer, Anarsia lineatella Zell. (Lepidoptera: Gelechiidae), in the Okanagan and Similkameen valleys of British Columbia

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The peach twig borer, Anarsia lineatella Zell. (Lepidoptera: Gelechiidae), in the Okanagan and Similkameen valleys of British Columbia

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Journal of the Entomological Society of British Columbia