Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/30/2010
Publication Date: 12/28/2010
Publication URL: http://ddr.nal.usda.gov/handle/10113/49482
Citation: Athanassiou, C.G., Arthur, F.H., Throne, J.E. 2010. Efficacy of methoprene for control of five species of psocids (Psocoptera) on wheat, rice, and maize. Journal of Food Protection. 73(12):2244-2249. Interpretive Summary: Insecticides are one tool for controlling insect pests of stored grain, but we are losing many stored-grain insecticides because of insect resistance and registration issues. We evaluated control of five species of pest psocids, which are emerging pests of stored grains, on stored wheat, rice, and corn after 40 days of exposure to an insecticide that is an insect growth regulator, methoprene, which has low mammalian toxicity. Methoprene did not completely suppress progeny production, but did cause a reduction in adult progeny in all psocid species; however, the numbers of immature psocids in the treated grains generally were not reduced by the methoprene. Our results indicate that the methoprene alone is not effective for control of the five psocid species tested. This information will help grain storage managers select protectant insecticides for control of stored-grain insects.
Technical Abstract: Psocids are emerging pests of stored grains and related commodities. These species are resistant to many neurotoxic grain protectants, which are usually effective against other major stored-grain pests. Insect growth regulators (IGRs) are promising alternatives to the currently used protectants; among these, methoprene is the only IGR that is registered for this purpose in the U.S. Methoprene was evaluated for control of five stored-product psocid species, Liposcelis bostrychophila Badonnel, L. entomophila (Enderlein), L. paeta Pearman, L. decolor (Pearman) (Liposcelididae), and Lepinotus reticulatus Enderlein (Trogiidae) at application rates of 1, 5, and 10 ppm on maize, wheat, and rice. For both treated and untreated commodities, fewer progeny were recorded on maize than on wheat or rice. Methoprene did not completely suppress progeny production, but did cause a significant reduction in adult progeny in all psocid species, especially at the application rates of 5 and 10 ppm. In contrast, in most cases, the number of nymphs in the treated grains did not differ significantly from those in the controls. Our results indicate that the application of methoprene alone is not effective against the five psocid species tested, and combinations of methoprene with other grain protectants should be evaluated.