Development and Validation of a Binomial Sequential Sampling Plan for Striped Cucumber Beetle (Coleoptera: Chrysomelidae) in Cucurbits

Adult striped cucumber beetles, Acalymma vittatum (F.), were sampled in 20 fields during 1994-1995 in southern Minnesota. Data in both years were collected using a fixed sample unit of 7 consecutive plants within a row and a fixed sample size of 48. Sample units of 1 through 7 plants were separated out from each data set, and data sets for each sample unit of 1, 2, 3, . . . 7 plants each, were used for analysis. The sampling plan was analyzed and validated using resampling software, Resampling validation for sampling plans, which uses the Wald sequential probability ratio test to develop a binomial sampling plan. Based on actual α (type I) and β (type II) error rates derived from the resampling analysis of 32-36 data sets, the optimum sample unit was determined to be 2 consecutive plants. Specifying nominal error rates of α = β = 0.10, with a tally threshold = 2 and an action threshold = 0.25, the sample plan required an average of 14, 2-plant sample units per field. Actual α and β error rates were 0.05 and 0.08, respectively. Analysis of the average sample number function indicated that a maximum of 29 samples would be required to classify A. vittatum populations near the action threshold of 0.25 proportion of samples infested with a tally threshold = 2. Binomial sampling plans should provide an efficient sampling program for use in managing A. vittatum infestations in cucurbits with minimal sampling costs.