Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: June 9, 1996
Publication Date: N/A
Mycotech Corporation of Butte, MT and the USDA-ARS Subtropical Agricultural Research Laboratory (SARL) of Weslaco, TX are pursuing development of Beauveria bassiana and Paecilomyces fumosoroseus for microbial control of whiteflies under a collaborative research and development agreement. The two fungal pathogens were found equally effective in laboratory bioassays and small-scale field trials; however, spore yields of B. bassiana were approx. four-fold greater than those of P. fumosoroseus under pilot-scale production conditions. In March 1995, a wettable powder formulation of B. bassiana strain GHA trade named Mycotrol WP was registered by the U.S. EPA for control of whiteflies and other homopteran pests. In initial field trials of this product using tractor-driven, conventionally-configured hydraulic and air-assist sprayers, coverage of the lower surfaces of melon leaves was poor and control inadequate (20-25%). Consequently, studies were initiated to improve coverage through manipulations of various spray parameters, including boom height, pressure, volume, ground speed, and nozzle spacing and orientation. Coverage was improved by reducing the spray angle, nozzle spacing, and distance from the target. In three cucumber fields, applications of Mycotrol WP made at 7 d intervals at average rates of populations by 60-70% within 3-4 weeks after initiation of the spray program; numbers of late-instar nymphs were reduced by 70-75%. This collaborative research is continuing, with the goal of developing fungal pathogens into reliable components of fruit and vegetable IPM systems.