Host Plant Choice of Colorado Potato Beetle and Variation in Defoliation and Yield Losses Among Organically Grown Commercial Potato Varieties
The Colorado potato beetle (CPB) is one of the most important pests of potato production in the United States. Given the limited insecticide options for organic producers, high expense of organic insecticides, and well-founded concerns over development of insecticide resistance in CPB, sustainable management tools for organic potato producers are sorely needed. The primary objective of this project is to clarify differences among commercial potato varieties in regard to CPB preferences and defoliation rates in order to establish the relative susceptibility of commonly grown commercial potato cultivars to CPB damage. Field experiments will be conducted at the University of Idaho Kimberly Research & Extension Center (Kimberly, ID) comparing the abundance of different life stages of CPB (eggs, small larvae, large larvae, and adults) and defoliation
rates over time among different commercial potato varieties. A total of at least ten different varieties will be used. The results will allow for evaluation of host preference of CPB and the importance of beetles on defoliation and yield within each variety. Variety-specific defoliation and yield data will allow economic analysis of potential returns and risks of organic versus commercial potato production in this region. This project will contribute to the development of sustainable organic potato production in several ways: (1) growers could produce less preferred varieties to limit CPB damage with fewer insecticide applications or (2) tailor a CPB management strategy to a variety's susceptibility; (3) reduced insecticide use would satisfy consumer demand for environmentally responsible production, (4) mitigate against insecticide resistance development, and (5) reduce input costs;
moreover, (6) varieties that are particularly attractive to CPB ultimately could be used in a trap cropping program. The use of more tolerant or less preferred varieties could be part of an overall integrated pest management strategy to reduce insecticide use and environmental risks while increasing yields and contributing to the long-term sustainability of organic potato production.