ECOLOGY, SAMPLING, AND MODELING OF INSECT PESTS OF STORED GRAIN, PROCESSING FACILITIES, AND WAREHOUSES
Location: Stored Product Insect Research Unit
Title: Efficacy of spinosad and methoprene, applied alone or in combination, against six stored-product insect species
Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 2010
Publication Date: March 21, 2011
Citation: Athanassiou, C.G., Arthur, F.H., Kavallieratos, N.G., Throne, J.E. 2011. Efficacy of spinosad and methoprene, applied alone or in combination, against six stored-product insect species. Journal of Pest Science. 84(1):61-67. doi: http://dx.doi.org/10.1007/s10340-010-0326-1.
Interpretive Summary: The lesser grain borer is the major pest of stored wheat in most of the world, and it has developed resistance to some of the insecticides used for its control. Thus, there is a need to develop alternative treatments for control of the lesser grain borer and other insect pests of stored wheat. We evaluated the bacterial insecticide spinosad and the insect growth regulator methoprene alone and in combination for control of six insect pests of stored wheat. Neither insecticide alone completely controls all insect pests of stored wheat. The specific combinations of spinosad and methoprene evaluated in our study would have no benefit over spinosad used alone for control of any of the six species tested.
Efficacy of the insecticides spinosad and methoprene, applied alone or in combination to wheat, was evaluated against six stored-product insect species, Rhyzopertha dominica, Sitophilus oryzae, S. granarius, Cryptolestes ferrugineus, Oryzaephilus surinamensis, and Liposcelis bostrychophila. The concentrations of the insecticides were 0.1 and 0.5 ppm for spinosad and 1 and 5 ppm for methoprene. Parental mortality of R. dominica was 100% on wheat treated with either rate of spinosad, with no progeny production in any combination treatment. Parental mortality of S. oryzae did not exceed 62%, and progeny production was not reduced by any insecticide treatment. All S. granarius adults exposed on wheat treated with spinosad alone at 0.5 ppm were killed, but parental mortality was reduced when methoprene was added. Progeny production was reduced in treatments containing spinosad. Mortality of adult C. ferrugineus was 97% or greater in treatments containing spinosad, but adult mortality of O. surinamensis and L. bostrychophila was not reduced by insecticide treatments. The specific combinations of spinosad and methoprene evaluated in our study would have no benefit over spinosad used alone for control of any of the six species tested.