Evaluation of the efficacy of a bassiana against the peach fruit fly, Bactrocera zonata (Saunders) (Diptera,: Tephritidae)

Abstract

Effect of entomopathogenic fungus Beauveria bassiana on mortality rate of the Bactrocera zonata (Saunders) (Diptera, Tephritidae) were concentration dependent, total mortality indicated that the B. bassiana at concentration of 10⁹ conidia /ml caused the maximum larval mortality (83.7%). The LC50 value was 1.4* 10⁶ conidia /ml.  In the same way, the effectiveness of the fungus was recorded on pupae, as the concentration 10⁹ conidia /ml gave the highest mortality rate (71.3%). There was a significant difference between susceptibility of larvae and the pupae that depends on the cuticle's thickness and spiracles.  The highest adult’s mortality was observed at 10 days post-treatment (90.33%) at the highest conidial concentration. The lowest LC50 against adult B. zonata was 1.8 *10³ conidia/ ml at 10 days post-treatment. Transmission of conidia from inoculated males to non-inoculated females was more pronounced compared to inoculated females to non-inoculated males, the first achieved 69.6 % mortality in females, the other achieved 60.1 % mortality rate in non- inoculated males.  This study indicates that B. bassiana has significant effects against B. zonata and that the conidia of the fungus could be successfully utilized as a biological insecticide.