Effects of the entomopathogenic fungus Beauveria bassiana on different stages of the pine processionary moth (Thaumetopoea wilkinsoni Tams)

Abstract: In this study, local isolates (from Isparta) of the entomopathogenic fungus Beauveria bassiana (Bals.) Vull. (BMAUM M6-4 and LD.2016) and BMAUM M6-4 were tested on second instar and late instar larvae of the pine processionary moth, respectively, under both laboratory and field conditions. The fungal isolates were tested on the second instar larvae at a concentration of 107 conidia/ml by dipping the pine leaves or spraying directly on larvae. For the late instar larvae under laboratory conditions, the fungal isolates were applied to the soil or spraying directly on the insect before the pupal stage. Under field conditions, larvae were collected with a special trap set up on pine trees and the isolates were applied to the soil or sprayed directly on the larvae. The second instar larvae were highly susceptible to the fungal isolates and 100% fungal infection was observed, at the latest, 5 days after application. The Beauveria bassiana BMAUM M6-4 isolate was used only on last instar larvae due to the observation of 100% infection on the third day after fungus application. The 100% infection value observed in the late instar larvae under laboratory conditions was determined as 75% and 93% for the direct fungus application to the soil and the insect under field conditions. In conclusion, local isolates of B. bassiana were determined to cause infection on early and late larval stages of the pine processionary moth. More detailed studies on the effectiveness of this isolate are needed under field conditions