A series of studies was conducted to determine the effects of temperature on toxicity of the insect growth regulator methoprene to eggs and larvae of Plodia interpunctella (Hübner), the Indianmeal moth. When methoprene was applied to Kraft paper at the rate of 0.0003 mg of active ingredient [(AI)]/cm2, there was little direct toxicity against eggs of P. interpunctella, and temperature did not affect insecticide efficacy. Similarly, exposure of eggs on a paperboard surface treated with different rates of methoprene resulted in delayed adult emergence but not a reduction in adult emergence. However, wandering-phase larvae ofP. interpuctella were susceptible to methoprene, and exposure of larvae for 0.5, 1, and 2 h on different packaging materials resulted in reduced adult emergence. There was variation in emergence depending on the specific surface, but temperature had no effect on resulting adult emergence from exposed larvae. A partial budget analysis described treatment costs and reduction of risks associated with control of eggs and larvae of P. interpunctella. Results indicate methoprene could be used in management programs to control larvae of P. interpunctella, but eggs may be able to compensate for exposure to methoprene residues on treated surfaces.

Aerosol insecticides may provide an alternative to fumigants for control of the Indianmeal moth, Plodia interpunctella (Hübner), the Indianmeal moth, 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 exposed to esfenvalerate alone. When eggs were exposed to methoprene, adult emergence of those exposed eggs was approximately 75%; however, when eggs were exposed to esfenvalerate, adult emergence was approximately 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.

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Brokken (1971a,b), McDonough (1971 and Scott and Broadbent (1972) using linear programming (LP). Optimal weights for buying and selling feedlot cattle have been considered in addition to optimal feeding programs by Meyer and Newett (1970) and Kennedy (1972)