Virulence of four Beauveria bassiana isolates on aestivating and overwintering populations of Eurygaster integriceps

In this study, virulence of four Beauveria bassiana isolates on aestivating and overwintering populations of Sunn pest (Eurygaster integriceps) adults was investigated. Bioassays were conducted and performed by spraying fungal spore ssuspension on adult sunn pest. Obtained data was analyzed to compare mortality in different treatments and to estimate LC50 and LT50. The results showed that overwintering adults of Sunn pest were more susceptible than the summer population. According to the results, LC50 of Fashand isolate was 1×108 and 2×105 spore/ml on aestivation and overwintering populations, respectively. LC50 of Spt-566 isolate was 3×107 spore/ml on the overwintering population. Estimated LT50 for Fashand isolate (109 spore/ml) on aestivating and overwintering populations were 13 and 7 days, respectively, whereas, estimated LT50 for Spt-566 isolate was 19 days on overwintering population. On the basis of this study, Fashand isolate was more effective than Spt-566 on two physiological stages of Sunn pest adult. The results also showed that adding oils to the suspension of the spores increase virulence of the isolates on all stages of sunn pest.