ARS | Publication request: MYCOINSECTICIDES

Submitted to: Integrated Pest Management Symposium Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 15, 2002
Publication Date: February 25, 2003
Citation: JARONSKI, S. MYCOINSECTICIDES - REGULATIONS AND RISKS. INTEGRATED PEST MANAGEMENT SYMPOSIUM WORKSHOP PROCEEDINGS. 2003. Proceedings, 4th National Integrated Pest Management Symposium, Indianapolis IN, April 8-10,2003. Presentation abstract. P. 24.

Technical Abstract: The USEPA risk evaluation of microbial pesticides with non-target insects involves a tiered system to provide a high degree of confidence that no unreasonable adverse effects are likely to occur. The agency's written assumption is that 'There should be very few microbials which require effects testing beyond the Tier I level.' While many insect pathogens show a degree of host specificity that is accommodated by this system, Deuteromycete fungi (e.g., Beauveria bassiana, Metarhizium anisopliae), which are receiving much recent commercial attention, are more generalist pathogens, with a variable but usually wide host spectrum, even on a strain level. My contention is that because many (most) Deuteromycetes are generalists, Tier 1 lab bioassays for acute pathogenicity, typically submitted for registration, can lead to exaggerated adverse effects. In nature, there are ecological and behavioral barriers to a significant impact on NTOs (and in some cases even the target insects). Establishment of these fungi in target populations, even after inundative release, has rarely been observed. Typically, impact on the target population decreases within a short time, unless the pathogen population is repeatedly and substantially replenished. I would like to illustrate my point by drawing on a couple of examples from my experience with Beauveria bassiana Strain GHA. Honeybees, whitefly parasitoids in melons, and heteropteran predators in cotton. With at least some of the generalist hyphomycetes, field assessments may be the only reliable predictive tool and should be emphasized. This strategy has a second beneficial outcome: learning how to integrate a MPCA with predators and parasites, rather than simply using the MPCA as a stand alone substitute for chemicals.