DisplayTitle

Detection of Fragments from Internal Insects in Wheat Samples Using a Laboratory Entoleter

^†Corresponding author. Phone: +1.785.776.2731. E-mail: daniel.brabec@ars.usda.gov
USDA-ARS Center for Grain and Animal Health Research, Manhattan, KS, U.S.A. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer.

A simple, rapid method that uses a small mechanical rotary device (entoleter) was developed for estimating insect fragment counts in flour caused by hidden, internal-feeding insects in whole grains of hard red winter and soft red winter wheat. Known counts of preemergent adults, pupae, and larvae of lesser grain borers and rice weevils were blended with 500 g samples of uninfested wheat. The entoleter impeller speed was adjusted based on grain hardness and moisture content to obtain about ≈98% intact and ≈2–2.5% broken kernels in an uninfested sample. The entoleter flung the wheat kernels against a surrounding steel ring. Approximately 70–90% of the insect-infested kernels, being weaker, released internal insect pieces upon impact. The broken kernels were sieved with number 10 and number 20 sieves to obtain large-sieved and small-sieved fractions, respectively. Insect pieces in sieved fractions were counted. The insect piece counts were correlated with the estimated flour fragments (R² = 0.94). The entoleter method can distinguish samples of grain containing 0, 25, or 75 fragments in 50 g of flour, with greater than 95% confidence. The method can be performed in approximately 5 min per 500 g sample and could potentially be a cost-effective method that grain handlers can use to inspect wheat loads for detecting insect damage and estimating insect fragments in flour.