Investigation on the pathogenicity of some Iranian isolates of Beauveria bassianaon the mulberry whitefly Aleuroclava jasmini sensu lato

Mulberry whitefly Aleuroclava jasmini sensu lato Takahashi 1932 as a sap feeder insect is one of the most serious pest in mulberry trees in Tehran province, Iran since 2016. The population of the species has increased due to lack of natural enemies in the new area. In this paper, virulence of four Iranian isolates of B. bassiana on second nymphal stage of A. jasmini sensu lato in five concentrations through spraying under laboratory conditions were investigated. The number of dead nymphs was recorded daily to 10 days. Mean mortality percentages were analyzed by AVONA under 95% of confidence level in SPSS. LC50 and LT50 were calculated by SAS. The final results from Probit test showed that the lowest LC50 produced by to two isolates, PTCC5197 and IRAN1359 as 1.3 × 105 conidia ml–1 indicated higher pathogenicity against A. jasmini sensu lato. The highest LC50 belonged to IRAN1228 with the value of 9.9 × 105 conidia ml–1 . LT50 results showed that by increasing the isolates concentration, mean lethal time decreases. It can be concluded that the studied isolates had high level of pathogenicity on A. jasmini sensu lato nymphs and it can be applied through IPM programs, indeed their environmentally safety would be so valuable.