Fungal entomopathogens in a tritrophic context

Variation in plant quality has an important impact on insect growth and development and there is considerable evidence that plants can also influence an insect’s natural enemies. Here we discuss the potential for plant-mediated effects on fungal entomopathogens. Fungi differ from other insect pathogens in that they infect an insect directly through its cuticle. This means that they are particularly vulnerable to changes in microclimate and properties of the insect cuticle. Potential direct and indirect mechanisms for plant-mediated effects on fungal entomopathogens are discussed. It is clear from these studies that fungal entomopathogens could be affected by plant volatiles and plant surface chemistry. Plant secondary chemicals can also inhibit fungal growth, potentially protecting the insect herbivore. However, the site of action and the mechanism behind these effects in plant-based studies is not always clear. The implications for biocontrol using fungal entomopathogens are discussed.