Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 10, 2006
Publication Date: October 15, 2006
Citation: Throne, J.E., Opit, G.P., Flinn, P.W. 2006. Seasonal distribution of psocids in stored wheat. Proceedings of the 9th International Working Conference on Stored Product Protection, p. 1095-1103. Technical Abstract: Psocids are an emerging problem in stored grain and in grain processing facilities in the United States. We conducted preliminary studies to determine which species of psocids were present in a feed mill, a grain elevator, and wheat stored in steel bins. We then conducted a more extensive study in steel bins containing wheat to determine temporal and spatial distribution of psocids in the wheat. We also compared use of cardboard refuges and grain trier samples for sampling psocids in the wheat. The predominant psocid species found in all locations was Liposcelis entomophila. In the study on temperospatial distribution, infestation levels before the bins were filled with wheat were low, but some psocids were present in the empty bins. Numbers of psocids in cardboard refuges on the wheat surface were low immediately after bins were filled in July, peaked in late September, dropped to almost zero in December as temperatures dropped during autumn and winter, and then remained at low levels until the study was ended in March. More psocids were found deeper in the grain than closer to the surface. During periods when psocid numbers were high, more psocids were found closer to the bin wall. Numbers of psocids in cardboard refuges was indicative of number of psocids in grain samples. The results indicate that cardboard refuges may provide an efficient method for sampling psocids in bins of wheat, and that psocid populations can increase quickly to high levels during storage even though they are low early in the storage period.