Biological control potential of entomopathogenic fungal strains against peach Fruit fly,<i>Bactrocera zonata</i>(Saunders) (Diptera: Tephritidae)

Abstract

The peachfruit fly, <i>Bactrocera zonata</i> (Saunders) is a polyphagous pest in nature, belonging to order, <i>Diptera</i> and their respective family is <i>Tephritidae</i>. It mostly feeds on different crops, vegetables and fruits. Different traditional chemical insecticides have been used to control this notorious pest. Excessive consumption of pesticides has become a major threat to the fresh fruits trade since many importing countries refused to accept the shipments due to public health and environmental concerns. There is a growing trend to control these pests using the most effective biological control methods and other preventive measures have been adopted for reducing their attacks. Fungal agents have been used as biological agents to manage the attack of different insects pest through biological means. The present study was conducted to assess the virulence of three entomopathogenic fungi, <i>Metarhizium anisopliae</i>, <i>Beauveria bassiana</i> and <i>Verticillium lecanii,</i> against <i>Bactrocera zonata</i> stages under different laboratory conditions. The results showed that <i>B. bassiana</i> and <i>M. anisopliae</i> were more effective in pathogenicity and potentially kill at all stages of <i>B. zonata</i> as compared to <i>V. lecanii</i>. The highest mortality rate for the third larval instar and the pupal stage were recorded after exposure to the 1 × 10¹⁰ conidia/ml concentrations, <i>B. bassiana,</i> with 68.67% and 89.67%, respectively. Adult <i>B. zonata</i> flies were the most susceptible to all entomopathogenic fungi. However, <i>M. anisopliae</i> was more virulent against <i>B. zonata</i> adult flies than <i>B. bassiana</i> and <i>V. lecanii</i> at 1 × 10¹⁰ conidial concentration. Therefore, the entomopathogenic fungi <i>B. bassiana</i> and <i>M. anisopliae</i> can be used as an cost effective bio-insecticide in the integrated pest management programs to control <i>B. zonata</i>. This study will be helpful to overcome this pest through biological control means.