Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 26, 2003
Publication Date: July 26, 2003
Citation: MCGUIRE, M.R. IMPACT OF BEAUVERIA BASSIANA ON WESTERN TARNISHED PLANT BUG.. SOCIETY FOR INVERTEBRATE PATHOLOGY ANNUAL MEETING. 2003.
The Western tarnished plant bug, Lygus hesperus, is a pest of many crops including strawberries, seed alfalfa and cotton. Damage to California cotton alone can reach hundreds of thousands of dollars annually. Currently, no specific controls exist and application of broad spectrum pesticides may eliminate natural enemies and flare secondary pests. Published laboratory studies suggested that Lygus species are susceptible to Beauveria bassiana but field tests with commercial isolates did not result in significant population reductions. In a search for natural enemies of L. hesperus in the San Joaquin Valley of California, adults and nymphs were collected from alfalfa fields and roadside vegetation and held individually in the laboratory. In virtually all fields surveyed and at all times of the year, B. bassiana was found infecting L. hesperus; in some samples, infection levels exceeded 50%. Intensive weekly sampling of several alfalfa fields over a two year period did not reveal a clear relationship between population size and percentage infection but B. bassiana was observed during climatic conditions normally not associated with the fungus. Laboratory studies demonstrated that isolates collected from the SJV could grow at temperatures exceeding 32° C suggesting adaptation to local climatic conditions. In addition, laboratory bioassays demonstrated that B. bassiana isolated from L. hesperus had much higher activity against L. hesperus than a commercial strain of B. bassiana. Experiments continue on strain characterization and the behavior of inoculated insects.