ARS | Publication request: Susceptibility of stored-product psocids to aerosol insecticides

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2012
Publication Date: November 15, 2012
Citation: Opit, G.P., Arthur, F.H., Throne, J.E., Payton, M.E. 2012. Susceptibility of stored-product psocids to aerosol insecticides. Journal of Insect Science. 12:139, 14pp. Available: http://www.insectscience.org/12.139.

Interpretive Summary: Psocids (insects which are also called booklice) are pests of stored grains and grain products in most of the world, and they have natural tolerance to some of the insecticides used for control of other stored-product insect pests, such as beetles and moths. Aerosol insecticides are used in flour mills and warehouses to control beetle and moth pests, but their effect on psocid pests needs to be determined. We evaluated two commonly used aerosol insecticides, methoprene and esfenvalerate, applied alone and in combination for control of four species of stored-product psocid pests. The greatest mortality of psocids attained was 76% for immature psocids and 62% for adult psocids, indicating that the aerosols did not provide effective control of the tested psocid species. This study shows that psocids may be tolerant to these aerosol insecticides when applied at rates that are normally effective for control of other stored-product insect pests. This information will help pest managers choose appropriate control strategies for psocid pests.

Technical Abstract: The efficacies of commercial methoprene and esfenvalerate aerosols for control of stored-product psocid pests were evaluated in simulated field studies. The efficacies of methoprene, esfenvalerate EC, the carrier Isopar-M™, and a combination of methoprene and esfenvalerate aerosols for control of Liposcelis decolor (Pearman) (Psocoptera: Liposcelididae) and Liposcelis entomophila (Enderlein) nymphs were assessed, and the effects of direct and indirect exposure of Liposcelis bostrychophila Badonnel, L. decolor, and Liposcelis paeta Pearman adults to esfenvalerate EC aerosol were evaluated. The greatest nymphal mortality attained was 76% indicating that the four aerosols tested were ineffective against L. decolor and L. entomophila nymphs. In the direct and indirect exposure studies, the greatest adult mortalities attained for the three psocid species were 62 and 32%, respectively. Based on these data, esfenvalerate aerosol is ineffective for control of L. bostrychophila, L. decolor, L. entomophila, and L. paeta psocid species. It is likely that aerosols of these insecticides are ineffective against other stored-product psocid pests as well. This study again shows that psocids are quite tolerant to many currently used insecticides when applied at rates that are usually effective against other stored-product insect pests.