Abstract
ABSTRACT Insect pests have remarkable capacity to develop resistance to insecticides. More than 600 species of plant feeding insect pests have developed resistance to insecticides. Management of insecticides resistance offers great promise as a complementary extension of integrated pest management (IPM). Insecticide resistance management (IRM) attempts to prevent or delay the development of resistance. A revival of interest in the use of microbial agents, especially entomopathogenic fungi in combination with sublethal doses of insecticide is increasing in insecticide resistance management. Integration of selected strain entomopathogenic fungi with selective insecticides can improve the control efficiency, besides decrease the amount of insecticides required, minimize the risks of environmental contamination and delay the expression of insecticide resistance in insect pests. Co-application of fungi like Beauveria bassiana, Metarhizium anisopliae, Nomuraea rileyi, Paecilomyces spp., Lecanicillium (=Verticillium) lecanii and Hirsutella thompsonii with suitable sublethal concentration of selective insecticide as two-in-one tank mix have been successfully employed against various insect pests to reduce the selection pressure insecticides and to avoid concurrent resistance risks in target pests. Majority of mechanisms of resistance occur through induction of enzymes especially mono-oxygenases and to some extent the esterases. Entomopathogenic fungi have ability to induce high degree of susceptibility to insecticides in target pests by suppressing enzyme activities and predispose them for fungal infection. This review outlines the current state of knowledge on the development of insecticide resistance in insect pests and discusses strategies for manipulation of certain important fungal entomopathogens as potential microbial tool in the insecticide resistance management programme for sustainable pest management systems.