Field studies were conducted in 1994 and 1995 to quantify the relationship between simulated striped cucumber beetle, Acalymma vittatum (F.), defoliation and yield loss in 'Carolina' cucumber. Six simulated defoliation levels (0-100%) were imposed over five time intervals in 1994 and nine simulated defoliation levels were imposed over six time intervals in 1995. Time intervals began at cotyledon, 1st, 2nd, or 3rd true-leaf, or 1st flower growth stages, and were terminated at either 1st flower or harvest. There were no significant differences among timing of defoliation treatments for continuous defoliation, and significant yield loss occurred only when defoliation was > 25% in both years. One-time simulated insect defoliation treatments showed no significant differences in timing of defoliation and significant yield loss occurred only at > 50% defoliation. Simulated defoliation results were used to estimate action thresholds. Results of the studies suggest that 'Carolina' cucumber can withstand high levels of defoliation before yield loss occurs, and that A. vittatum damage is primarily a concern during early plant growth stages.
Bibliographical noteFunding Information:
We would like to thank David Bartels, Sandy Bird, Patricia Bolin, Laurie Cooper, Mike Espinosa, Gloria Gingera, Brady Lenzen, Andy Miller, Patrick O’Rourke and Tina Sonterre for field assistanceA. special thanks to Randy Wewetzer (M. A. Gedney Co.) for supplying ‘Carolina’ seed and technical assistancer egarding cultural practices for cucumber. We thank Drs Ted Radcliffe and Ken Ostlie (Department of Entomology, University of Minnesota) for their suggestionsa nd Dr. Robert Stucker (Agronomy and Plant Genetics, University of Minnesota) for review of the experimentald esign.W e also thank Dr Leon Higley (Department of Entomology, University of Nebraska) for his help with photosynthesise quip-ment and measurementsa nd Dr Mark Westgate (Department of Agronomy and Plant Genetics, University of Minnesota) for use of photosynthesis equipment. We thank Drs Leon Higley, Robert Peterson (DowElanco) and David Buntin (Department of Entomology, University of Georgia) for their comments and suggestionsi n reviewing an earlier draft of this paper. This work was supported by the North Central Region Pesticide Impact Assessment Program, Project # 583 (Ohio State University Research Fund # 675841)‘ Loss of Furadan 1SG for Cucumber Beetles on Cucurbits: Biological, Environmental and Economic Impact of Alternatives’, and the University of Minnesota Agricultural Experiment Station. This is publication 971170108o f the Minnesota Agricultural ExperimentS tation.
- Acalymma vittatum
- Action threshold
- Yield loss