Preliminary study of a Georgian isolate of Isaria fumosorosea Wize against Lymantria monacha and L. dispar

The virulence of an isolate of  Isaria fumosorosea, isolated from pupae of Hyphantria cunea Drury in Georgia was evaluated to determine its potential as a biological control agent of Lymantria monacha L. and L. dispar L. larvae under laboratory conditions (24 ± 2°C, 70 ± 5% R.H and 16:8h L:D). L. monacha larvae were collected in Lieberose (Southern Brandenburg, Germany) on Pinus sylvestris  trees and L. dispar  larvae originated from a laboratory strain of the insect (New Jersey standard-strainfrom USA). A conidial suspension of 1*108 conidia/ml for both - L. monacha and L. dispar larvae was used for the experiments. Two different methods, dipping of the larvae in the suspension or exposing  the larvae to the fungal suspension on filter paper were used for the infection. The results of this preliminary study suggest that larvae of both species were tolerant to the induced mycoses caused by I. fumosorosea isolate.  In order to improve the lethal effect of this isolate,  re-isolates from L. dispar and L. monacha were obtained and further experiments will be conducted.