Oviposition and feeding by Bactericera cockerelli (Homoptera: Psyllidae) in response to a solar protectant applied to potato plants

Abstract The potato psyllid, Bactericera cockerelli (Sulc), is a major concern for potato growers as it vectors the pathogen responsible for “zebra chip” disease. Current management practices of potato psyllids in commercial potato ( Solanum tuberosum L.) fields are based almost exclusively on insecticide applications with as many as 6–8 applications in individual potato fields during the growing season. As a complement, and to reduce the reliance on insecticides, it might be advantageous to apply biorational insecticides, which alter the attractiveness of potato plants to feeding and ovipositing potato psyllids. In this study, we evaluated two biorational insecticides: a limestone particle film (Purshade ® ) and a plant growth regulator (prohexadione-calcium, Apogee ® ), as both have documented repellency to insects when applied to crop plants. Based on experimental applications to potato plants and subsequent no-choice and choice studies with potato psyllids, prohexadione-calcium had no significant effect on leaf probing activity or oviposition. We found that limestone particle film treatment caused a small but significant reduction in oviposition between 7 and 14 days after application, while probing activity was unaffected. Examination of spectral reflectance indicated changes resulting from application of the limestone particle film. We propose that differences in reflectance may indicate changes in photosynthesis and plant physiology that subsequently alters the suitability of potato plants as hosts for potato psyllids. This interesting possibility, and the utility of limestone particle films as part of potato psyllid management strategies in potatoes is discussed.