در شرايط آزمايشگاهي )Euproctis chr/sorrh؟al( روي لاروسن سوم پروانه دم قهوه اي بلوط )Verticillium Lecani=Lecanicillium muscarium( بيمارگري قارچ

Pathogen city of Verticillium lecanii (=Lecanicillium muscarium.) on brown tail moth Euproctis chrysorrhoea (L.) larvae, at laboratory condition

Brown tail moth, Euproctis chrysorrhoea is an important defoliator of oak and a number of hardwood tree species. Its irritant hairs make it a sanitary important insect on humans. Introduction of a suitable biological agent with the other control measures is quite important especially in the case of population outbreaks. V. lecanii strain DAOM 198499 grown on a solid culture medium was used for pathogenicity and bioassay procedures. Suspensions of 104, 105, 106, 107 and 108 conidia/ml with a control (distilled water) containing Triton X-100 were used on third instars larvae in a complete randomized design with three replications. In other experiments, treatments included two suspensions (106 and 108 conidia/ml) and two durations of 97±2 percent RH supply (24 and 48 hours after spore application), with or without desiccant material on third instar larvae. A factorial complete randomized design was applied. In the first experiment suspensions of 107 and 108 conidia/ml gave a significantly better result than the others (p<0.01). LC50, determined by proc probit analysis required a concentration of 7.2xl06 conidia/ml. Over 50% larval mortality was observed only in 107 and 108 conidia/ml suspensions, and LT50 was measured by life test procedure as 7 ± 0.31 and 5 ± 0.22 days, respectively. Maintenance for 48 hours at high RH gave an average mortality rate of 90.95%, significantly different from the 40.44% mortality rate after 24 hours (p<0.01). This is the first report of the pathogenicity of this strain of Verticillium lecanii on brown tail moth larvae.