Submitted to: Western Society of Weed Science
Publication Type: Abstract only
Publication Acceptance Date: 12/1/2001
Publication Date: 3/1/2002
Citation: WILLIAMS, M.M., WALSH, D.B., BOYDSTON, R.A. INTEGRATING CHEMICAL AND BIOLOGICAL CONTROL FOR SUPPRESSION OF VOLUNTEER POTATO. PROCEEDINGS WESTERN SOCIETY OF WEED SCIENCE. 55:30, #60. 2002. Interpretive Summary:
Technical Abstract: Few studies have evaluated interactions between herbicide-induced stress and arthropod herbivory on weed fitness, moreover, the significance of such interactions at an integrated pest management level is unknown. A model study system is being developed that focuses on suppression of a Solanaceous weed with an oligophagous grazer, sub-lethal herbicide doses, cultivation, and crop competition. Volunteer potato (Solanum tuberosum L.) is poorly controlled in several Pacific Northwest potato rotation systems, causing significant yield loss and serving as an alternate host and viral vector for serious pests of potato. Colorado potato beetle (Leptinotarsa decemlineata Say) is a potato pest because of its ability to defoliate the plant and reduce yield, however, the beetle grazes on many Solanaceous weeds and is currently controlled in Pacific Northwest potato production. Elsewhere, Colorado potato beetle has expressed resistance to most classes of insecticides used on the beetle and maintaining a reservoir of susceptible individuals in beetle populations is cited as important for mitigating further insecticide resistance. Literature indicates the beetle is attracted to potato stressed chemically and physically, although extent of anemotaxis to herbicide-injured plants is unknown. We are developing functional relationships between fluroxypyr dose and beetle density on weed fitness. Recognizing this research is in its infancy, early findings indicate the biologically effective herbicide dose may be reduced 50% and more when coupled with modest levels of beetle grazing in the greenhouse. The overall goal is to develop integrated pest management systems for a problematic weed that escapes conventional management tactics.