Molecular characterization, virulence and horizontal transmission of B eauveria pseudobassiana from D endroctonus micans ( K ug.) ( C oleoptera: C urculionidae)

The great spruce bark beetle, D endroctonus micans ( K ugelann) ( C oleoptera: C urculionidae), has been a potential threat for T urkey and the entire E urasian spruce forests for many years. Control strategies which have been applied so far are still insufficient to prevent its damage. A previous study has shown that a B eauveria isolate ( ARSEF 9271) proved to be an efficient microbial control agent against the great spruce bark beetle. In this study, this isolate was identified as B . pseudobassiana based on the partial sequence of EF 1‐ α and ITS sequence. A conidial suspension (1 × 10 8 /ml) of this fungus caused 100% mortality on both larvae and adults of D . micans within 5 and 6 days, respectively. Also, it caused 100% mycosis value on both larvae and adults. Mortality values of horizontal transmission experiments between larvae and adults which were contaminated with 1 × 10 6 /ml spore suspension at 25%, 50%, 75% and 100% rates were determined as 100% after 15 days at 20°C under the laboratory conditions. We also determined the decrease of the damage in spruce wood block (15 × 25 cm) when the contamination rate of the larvae was increased. Our results indicate that B . pseudobassiana ARSEF 9271 seems to be a very promising biocontrol agent against D . micans .