Development and evaluation of sequential sampling plans for Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae) infesting farm-stored wheat

The development and evaluation of appropriate sampling plans are needed for cost-effective management of stored-product insects. Sequential sampling plans, which are based on a variable sample size, are generally more cost effective than plans based on a fixed sample size. For adults of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), we developed sequential sampling plans based on complete counts and the presence/absence of insects in 0.5 kg grain samples removed with a trier from the top 1 m of wheat stored in farm bins. Insect count data were used to develop a sampling plan for estimating the density of C. ferrugineus with a fixed level of precision. The presence/absence data were used to develop a sampling plan for classifying the C. ferrugineus infestation level relative to an action threshold. The performance of these sampling plans was evaluated (validated) using independent data sets anti an IBM-PC software program specifically designed to test the plans. This is the first paper illustrating the development and evaluation of sequential sampling plans for a stored-product insect.