- Vegetables: cucurbits
- Education and Training: extension
- Pest Management: biological control, chemical control, cultural control
Organic growers expect heavy beetle damage, spread of bacterial disease, and low yields for cucurbit crops. For farms that depend on cooperative share holders or retail farm markets, a successful crop of cucurbits can be very profitable. Growers would welcome information on biological control of beetle pests. Previous studies on cucumber beetles have demonstrated the potential of biological control methods, but none have produced methods that can be readily adopted. We began research on the topic in 2003 by taking a survey of the presence of the striped cucumber beetle parasitoid fly and investigating adult cucumber beetle susceptibility to entomopathogenic nematodes. We found that the fly, Celatoria setosa, was parasitizing beetles at relatively low percentages on all collaborating farms, and that mortality for adult beetle treated with entomopathogenic nematode Heterorhabditis bacteriophora strain GPS-11 was higher than beetles not treated with nematodes (Miller, unpublished 2003). If adult beetles and the negative impacts of beetle feeding can be reduced by either the enhancement of fly parasitoid Celatoria setosa or by inundative applications of entomopathogenic nematode Heterorhabditis bacteriophora, then organic growers can adapt these biological control methods. The fly parasitoid enhancement experiment was attempted in 2003 at the OSU Waterman Research Farm, but was inconclusive due to heavy weed pressure and an inadequate bloom time of the flowering border provided to enhance resources. Repeating the experiment in 2004 with adjustments to the experimental design provided some results. In conjunction with the research farm, three collaborating commercial growers agreed to test a floral resource borders in their cucurbit crops in 2004. We assigned plots with one of two treatments: flowering borders of mixed Phaecelia tancetifolia and Trapoleum majus and no flowering borders. We collected 100 adult beetles, monthly from June-September, from each of the 4 repetitions and observe parasitism and collect data on percent parasitism. The objective of the field experiment with Heterorhabditis bacteriophora was to evaluate whether nematodes (Heterorhabditis bacteriophora) can be effective for adult beetle control during the flowering and fruiting stages of pumpkin. We compared spray applications of chemical insecticide, Sevin, to spray applications of nematodes. During the pumpkin flowering stage, 3 treatments were administered to evaluate late season adult beetle control from the following nematode sprays: 1) high rate 2) moderate rate, and 3) water alone for a control. Sprays began in mid-July and continued every two weeks until September. Data was recorded on beetles per flower, beetle damage, and overall yield. Results will be published in a M.S. Thesis and submitted to a peer-reviewed journal.
Project objectives from proposal:
The objectives of this project were to evaluate methods of biological control for striped cucumber beetle, Acalymma vittatum, in pumpkins. The initial collabortaive objective was to assess the potential of adoption of biological control practices by pumpkin farmers which was determined by a questionnaire survey. The research objective was to conduct experiments on the efficacy of applying and enhancing biological control organisms in the field. Output objectives were: report research findings at agricultural field days and growers organizations, publish research results in Master of Science thesis and scientific journals, and to develop a fact sheet on the natural enemies of striped cucumber beetle for use by entomology extension. The overall educational objective of this project was to inform farmers of the presence of natural enemies in their pumpkin crops and to report research results that could lead to a sustainable pest control method for striped cucumber beetle.