Use of entomopathogenic fungi for the control of stored-product insects: can fungi protect durable commodities?

Entomopathogenic fungi are considered promising microbial control agents for the control of post-harvest insects, and their evaluation for this purpose has lately attracted a significant amount of research. They are naturally occurring, environmentally safe organisms that infect insects by contact. Insect fungal pathogens have a broad spectrum of hosts, can be mass-produced easily, rapidly and economically and can be applied with the same technical means as conventional contact insecticides. In this context, the most studied fungal species for the control of stored-product insect species are Beauveria bassiana and Metarhizium anisopliae. Both fungal species have a wide host range and have been tested against most of the major stored-product insect pests. The effect of biotic and abiotic factors on the virulence and success of entomopathogenic fungi in storage insect control, as well as the combined application of these agents with other pest control technologies, is reviewed here. Temperature and relative humidity influence the efficacy of entomopathogenic fungi, often with variable results, whereas the combined use of entomopathogenic fungi with diatomaceous earth in many cases has a synergistic or additive effect. Alternative methods of entomopathogenic fungi application, based on the lure-and-kill approach, are proposed, and future challenges for the use of entomopathogenic fungi against stored-product insects are highlighted.