Interaction between Entomopathogenic Nematodes and Entomopatogenic Fungi in Microbial Control

Entomopathogenic fungi and entomopathogenic nematodes are globally distributed soil organisms capable of infecting and killing a wide variety of insects. Therefore, these organisms are frequently used as biocontrol agents in insect pest management. Both entomopathogenic fungi and nematodes share the soil environment and therefore can infest and compete for the same insect host. However, natural co-infections are found rarely due to the cryptic soil environment. Our current knowledge on their interaction within the host comes mainly from laboratory experiments. Due to a recent trend of combining biocontrol agents to increase their efficacy, many studies focused on the co-application of different species of EPF and EPNs against various insect pests with variable outcomes for instance, synergistic effect, additive effect, and antagonism. Also, the effect on the development and reproduction of each pathogen varied from normal reproduction to exclusion, and generally, the outcomes of the interactions were dependent on the pathogen and host species, pathogen doses, and timing of infection. The present review aims to summarize current knowledge on the interactions of entomopathogenic fungi and nematodes within an insect host and estimate the possible effects of the interactions on natural pathogen populations and their use in microbial control.