Selection of highly virulent entomopathogenic fungal isolates to control the greenhouse aphid species in Iraq

Abstract

Aphids are one of the major insect pests of greenhouses and field crops worldwide. Several species of entomopathogenic fungi (EPF), including Lecanicillium spp. Beauveria bassiana, Isaria fumosorosea and Metarhizium anisopliae, have been developed commercially to control aphid species. However, there are no commercial products based on EPF that have been registered in Iraq. This study, therefore, was conducted to evaluate the virulence of four isolates of EPF, including, B. bassiana, Lecanicillium lecanii, M. anisopliae and Chaetomium globosum to select the highly virulent ones against the greenhouse aphids. Although the isolate of L. lecanii had the highest virulence against all tested aphid species in the laboratory bioassay, Myzus persicae Sulz and Aphis gossypii Gloy were more susceptible than Aphis fabae and Macrosiphum euphorbiae to infection with L. lecanii. Mortality caused by L. lecanii 7 days post-treatment with 108 conidia ml−1 was 100%. Further experiments in the greenhouses showed that L. lecanii significantly reduced the density of both M. persicae and A. gossypii 5 days after fungal applications. This isolate shows a promise for development of an alternative control agent against M. persicae and A. gossypii in Iraq.