Harvesting and Storing Wheat--Good News, and Bad

Newly harvested wheat is generally not infested with insects, an Agricultural Research Service scientist reports. Now for the bad news: Insects immigrate into grain bins within 30 days after harvest. That’s the word from Manhattan, Kan., where the researcher is counting insects immigrating into grain bins from the outside.

Entomologist David W. Hagstrum used traps to monitor 34 grain bins on 12 different Kansas farms. The traps allowed him to check the numbers of insects entering through openings between the roof and bin cap and under the eves, between the roof and the bin wall. Bin sizes ranged from 1,000 to 8,000 bushels. On a average, 14 rusty grain beetles, six lesser grain borers, six foreign grain beetles, and 22 hairy fungus beetles immigrated into these bins each day during the first month of storage.

Hagstrum and ARS entomologist Paul W. Flinn will use this information to strengthen the accuracy of Stored Grain Advisor (SGA), a personal computer model developed to help grain managers select the best timing for control methods. Such guidance can help reduce the cost of insect pest management. A special form of SGA developed for use in large grain elevators--SGA Pro--is being released in beta version for use by grain elevators in the Kansas-Oklahoma area-wide IPM project this fall. The public can obtain a copy of SPA Pro from Flinn in the spring of 2001.

Each year, more than 2 billion bushels of wheat are produced in the United States, with most of it stored in a grain elevator at some point. Some is stored before milling. Much stored grain is awaiting export to other countries. In either case, stored grain insect pests such as the lesser grain borer, rice weevil, red flour beetle and rusty grain beetle cost the U.S. wheat industry about $500 million annually.

ARS is the chief scientific research agency of the U.S. Department of Agriculture.

Scientific contact: David Hagstrum, ARS Grain Marketing and Production Research Center, Manhattan, Kan., phone (785) 776-2718, fax (785) 776-0962, hagstrum@usgmrl.ksu.edu.