Ecological considerations in producing and formulating fungal entomopathogens for use in insect biocontrol

Abstract

Insect pests persist in a wide-variety of agricultural, arboreal and urban environments. Effective control with fungal entomopathogens using inundation biocontrol requires an understanding of the ecology of the target insect, fungal pathogen, and the insect-pathogen interaction. Historically, the development of production and formulation processes for biocontrol fungi has primarily focused on reducing costs by maximizing the yield of infective propagules, increasing storage stability, and improving product form for ease of application. These goals are critical for commercialization but are often in conflict with environmental and ecological considerations. Critical parameters for selecting a fungal pathogen for use in inundation biocontrol include the cost-effective production of a stable, infective propagule that is suited for use in the environment where the insect must be controlled. Production processes can be manipulated nutritionally and environmentally to produce efficacious propagules or to direct fungal differentiation to propagule forms that may be better suited for use in specific environments. Formulation development must also consider ecological and environmental factors to maximize biocontrol efficacy. A basic understanding of the surface chemistries of the fungal propagule and insect, the interactions between a fungal propagule and the insect cuticle that lead to infection, and the impact of the environment on this interaction can aid in the development of effective formulations.