PARASITOID ASSEMBLAGES ISOLATED FROM EXTERNALLY FEEDING LEPIDOPTERANS AND CODLING MOTH (CYDIA POMONELLA L., TORTRICIDAE) IN A YOUNG APPLE ORCHARD IN WEST BULGARIA

VELCHEVA, N., A. ATANASSOV, O. KARADJOVA and Z. HUBENOV, 2012. Parasitoid assemblages isolated from externally feeding lepidopterans and codling moth (Cydia pomonella L., Tortricidae) in a young apple orchard in West Bulgaria. Bulg. J. Agric. Sci., 18: 675-681 During the period 2005 – 2009, a gradual increase in the rate of insect parasitism was observed on externally feeding Lepidoptera developing on buds, flowers, leaves and fruits of young apple trees in an orchard located in West Bulgaria. The aim of the present study was to investigate the biodiversity of parasitoids associated with the lepidopteran complex and the codling moth in this orchard. The role of natural enemies for suppressing pest populations was estimated as well. During the five-year survey, 19 parasitoid species belonging to 6 families were identified. Species of family Ichneumonidae were dominant (42.1%), followed by Braconidae (31.6%). Three other families, Pteromalidae, Chalcidae, and Encyrtidae, were represented by one species each and accounted for 5.3 % of the abundance of the established parasitoid complex. Two tachinid flies were isolated, corresponding to 10.5 % of the complex. Dibrachys cavus (Walker, 1835) was the first parasitoid observed during the investigation and was found as cocoons on the leaves. Scirtetes robustus (Woldstedt, 1877) parasitized Orthosia cerasi (Fabricius, 1775) in the second year after planting of the orchard. Aporia crataegi (Linnaeus, 1758), Hedya nubeferana (Haworth, 1811) and Operophtera brumata (Linnaeus, 1758) exhibited the highest rates of parasitoid infestation within the complex of externally feeding lepidopteran larvae. The percentages of parasitism reached to 25% for the first two pests and 22 % for O.brumata. The rate of parasitism of codling moth collected in the young orchard was low: 5.3% in 2008 and 0.9% in 2009. Liotryphon caudatus (Ratzeburg, 1848) and Ascogaster quadridentata (Wesmael, 1835) were the first species established to infest the larvae of the pest. The ichneumonid wasp Glypta pictipes (Taschenberg, 1863) is a new species for the Bulgarian fauna. Pimpla arcadica (Kasparyan, 1973), isolated from codling moth, is a new distributional record for the parasitoid, and four new parasitoid - host relationships were established for the country: Diadegma armillata (Gravenhorst 1829) was reared of Coleophora hemerobiella (Scopoli 1763), Compsilura concinnata (Meigen 1824) of Aporia crataegi (Linnaeus 1758), Protapanteles vitripennis (Curtis 1830) of Yponomeuta malinellus (Zeler 1938), and Lissonota dubia (Holgren 1856) of Choristoneura hebenstreitella (Muler 1764).