Pathogenicity, formulation and storage of insect pathogenic hyphomycetous fungi tested against Diabrotica speciosa

Abstract

Studies were conducted to search for fungal strains with potential pathogenicityagainst Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae). Among sixteen fungalisolates screened the most virulent was a Beauveria bassiana (Balsamo) Vuillemin isolate(FHD13) that caused 70% mortality of D. speciosa third instar larvae. The LC50 value ofB. bassiana isolate FHD13 was 3.48 × 1010 conidia/ml. Different temperatures (4, 17 and26 ◦C) and vegetable oils (corn, sunflower and canola) used for storage did not significantlyaffect viability of conidia. A pathogenicity trial against D. speciosa larvae performed with thecorn oil formulation (1 × 108 conidia/ml of oil) caused 65% of mortality.