Insect Infestations in Wheat and Corn Exported from the United States

Abstract

The incidence of insects in wheat and corn for export from the United States was determined in grain loaded at 79 port terminals in the United States and Canada (the St. Lawrence Seaway) during a 2-year period from January 1977 to December 1978. One or more live, stored-product insect species were found in 17.9% of the wheat samples and 22.4% of the corn samples. Insects of the Genus Sitophilus were the predominate ones in all samples, with 7.7% of the wheat samples containing an average of 4.2 weevils per 1,000 and 14.4% of the corn samples containing an average of 5.8 weevils per 1,000 g. Cryptolestes was the second most frequent genus of insect pests, with 7.5% of the wheat and 9.7% of the corn containing averages of 1.9 an 2.4 insects per 1.000 g. respectively. The lesser grain borer. Rhyzopertha dominica (F.), was third among species found in wheat, and the Indian meal moth, Plodia interpunctella (Hübner), was third among species in com. Insects were detected most often in wheat from the Gulf and Great Lakes regions (23.8%) and in com from the Great Lakes and Atlantic Regions (23.5 to 24%). Grain from the Pacific region contained the fewest insects. The highest incidence of insects generally occurred in September or October.