|JENSON, EMILY - Kansas State University|
|NECHOLS, JAMES - Kansas State University|
Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2009
Publication Date: 2/15/2010
Citation: Jenson, E.A., Arthur, F.H., Nechols, J.R. 2010. Efficacy of an Esfenvalerate plus Methoprene Aerosol for the Control of Eggs and Fifth Instars of Plodia interpunctella (Lepidoptera: Pyralidae). Insect Science. 17: 21-28.
Interpretive Summary: Aerosol insecticides are used to control beetle pests inside flour mills and other facilities, but there is little published information regarding control of the Indianmeal moth, a primary pest of stored foods. We evaluated two registered insecticides for their ability to control eggs and late-stage larvae of the Indianmeal moth. Methoprene, an insect growth regulator, was effective on larvae but not as effective on eggs. Esfenvalerate, a pyrethroid, was not effective on larvae but gave some control on eggs. Using both insecticides in combination gave more complete control of eggs and larvae, and the combination treatment was also supported by an economic analysis.
Technical Abstract: Aerosol insecticides may provide an alternative to fumigants for control of the Indianmeal moth, Plodia interpunctella (Hübner), a major insect pest of stored processed food. In this study, eggs and larvae (5th instars) of P. interpunctella were exposed to aerosol applications of the pyrethroid esfenvalerate and insect growth regulator methoprene, alone and in combination, in open and obstructed positions inside small sheds. When larvae were exposed to methoprene alone, adult emergence from those exposed larvae was 7.1 ± 1.5%. In contrast, adult emergence was 92.5 ± 3.5% when larvae were treated with esfenvalerate alone. When eggs were exposed to methoprene, adult emergence of those exposed eggs was about 75%; however, when eggs were exposed to esfenvalerate, adult emergence was about 35%. In the combination treatment of methoprene plus esfenvalerate at their respective label rates, adult emergence following larval exposure was 0.91 ± 0.61% compared to 16.3 ± 9.6% when eggs were exposed. Based on our results, methoprene alone is highly effective in reducing adult emergence after larval exposure, however, it is not as effective on eggs as esfenvalerate. A combination treatment of esfenvalerate plus methoprene could be used to control eggs and the wandering-phase larval stages of P. interpunctella. An economic risk analysis also supports a strategy of combining methoprene and esfenvalerate.