Dispersion of stored grain insect pests in a wheat‐filled silo

Abstract

Abstract The distribution of insects in a wheat‐filled large concrete silo was studied by drawing grain samples from the whole vertical depth by means of a special probe. The major insect species found were: Trogoderma granarium (Khapra beetle), Rhyzopertha dominica (Lesser grain borer), and Tribolium castaneum (Red flour beetle). Maximum activity of all species was found on the grain surface although some insects were found at all depths in varying numbers. Breeding activity of major insect pests was detected by incubating grain samples and then counting the number of emerged insects. Maximum emergence of T. granarium and R. dominica was observed in nearly all grain depths in October to November and July to November, respectively. Maximum emergence of T. castaneum was noted in almost all grain depths during August. Breeding activity of all species was mainly restricted to the grain surface and top grain layers during the months of November and December.