On the Pathogenicity of Entomopathogens to the Peach Fruit Fly, Bacterocera zonata (Saunders) (Diptera: Tephritidae)

A study to evaluate the pathogenicity of entomopathogenic nematodes and fungi against the peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) was carried out under laboratory conditions. The nematodes species tested were; Heterorhabditis bacteriophora; Steinernema carpocapsae and S. riobrave. The fungi were; Metarhizium anisopliae and Beauveria bassiana. Different concentrations were used against immature stages of B. zonata, by contact and/or soil inoculation techniques. Results showed that both Steinernema species were more effective on full-grown larvae than H. bacteriophora in contact treatment, whereas H. bacteriophora was more effective in soil, as it induced higher mortality of B. zonata pupae at both techniques. Mortality rates of B. zonata pupae increased significantly by increasing the concentration of the two tested fungi at the same time of exposure. Adult mortality was affected by soil treatments as B. bassiana treatments significantly increased mortality rates compared to M. anisopliae and control treatments. Emerged adults from treated pupae with both fungi showed mycosis on the outer surface, additionally some emerged adults showed malformation and mostly failed to emerge. Results suggested that entomopathogenic nematodes and fungi can be used as alternative tools of pesticides for controlling B. zonata after validating protocols of field conditions.