ENTOMOPATHOGENIC NEMATODES AND FUNGI AS BIOCONTROL AGENTS FOR

Abstract

Peach fruit fly Bactrocera zonata (Saunders) and Mediterranean fruit fly Ceratitis capitata (Wiedemann) are serious and destructive pests of fruits and vegetables in Egypt, tropical and subtropical regions in the world. They cause high lose of fruit production annually. The frequent use of chemical insecticides to control these pests is resulting in many problems such as environmental pollution, reduction of natural enemies of pests, pesticide residues on products and development of more resistant and virulent strains of pests. There is a need in the whole world to develop safe and effective alternative methods for controlling these pests. Bioagents such as entomopathogenic nematodes and fungi can act the role of environmentally friend alternative to chemical insecticides. In the present study entomopathogenic nematodes Steinernema riobrave (Cabanillas) and Heterorhabditis bacteriophora (native strain) were used for biological control of B. zonata and C. capitata and the obtained results were summarized as follow: • Full-grown larvae of both insects were susceptible to infection by both nematode species and the percentage of larval 􀀉 Summary 147 mortality increase by increasing concentration of infective juveniles of the tested nematode. • Full-grown larvae of both insects were more susceptible to infection by both nematode species than different pupal ages. As pupal ages increase the susceptibility to nematode infection decreases. The results also showed that, H. bacteriophora (native strain) was more virulent to both insects than S. riobrave. • Heterorhabditis bacteriophora infective juveniles were more able to find captivated larvae of both insects than S. riobrave. • Effect of different soil moisture levels on pathogenicity of the tested nematodes was studied and the results showed that, pathogenicity of both S. riobrave and H. bacteriophora was increased by increasing soil moisture. Also nematode persistence in the soil was affected by soil moisture. • The study also showed that both S. riobrave and H. bacteriophora nematodes were more pathogenic at 30 °C than at 20 °C. Heterorhabditis bacteriophora caused higher mortality to B. zonata and C. capitata at both tested temperature (20 and 30 °C) than S. riobrave. 􀀉 Summary 148