Pathogenicity of the entomopathogenic fungus, Beauveria bassiana (Bals.) Vuill. endophytic and a soil isolate against the squash beetle, Epilachna chrysomelina (F.) (Coleoptera: Coccinellidae)

Abstract

AbstractLaboratory and field bioassays were conducted to evaluate the pathogenicity of an endophytic and a soil isolate of the entomopathogenic fungus, Beauveria bassiana (Bals.) Vuill. against different stages of squash beetle, Epilachna chrysomelina (F.) (Coleoptera: Coccinellidae). Both isolates were identified by ITS rDNA sequence analysis. Both isolates were pathogenic to the squash beetle; however, their potential was different according to the conidia concentration and the exposure period. Three days post treatment, (100%) mortality rate was obtained, when the first and second larval instars were treated by the B. bassiana ES (soil isolate) compared to 83.67 and 72.60%, respectively when treated with the endophytic isolate. A percentage of 17.67% malformation occurred among the adults that emerged from treated pupae. The highest mortality percentage under field conditions were 28.67 and 22.33% for larvae and adults, respectively.