Sublethal effects of methoxyfenozide on reproduction of the Mediterranean flour moth, Ephestia Kuehniella Zeller

Methoxyfenozide is a lepidopteran-specific insecticide belonging to a new class of insect growth regulator, the non-steroidal ecdysteroid agonists. The effects of methoxyfenozide (RH-2485) on growth and reproduction of the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), an important pest in stored products worldwide, were evaluated under laboratory conditions. Topical application on newly emerged pupae induced precocious and lethal adult exuviation. Moreover, it reduced pupal stage duration and inhibited adult exuviation with an LD50 of 0.01 mu g/pupa and LD90 of 0.37 mu g/pupa. In a follow-up experiment, the adults that survived from treated pupae were investigated for different reproductive event parameters. The treated adults showed a dose-dependent increase in pre-oviposition period, and a decrease in oviposition period and in ovary growth parameters, which in turn resulted in a lower fecundity and egg viability. Typically, the ovaries in treated females contained lower amounts of free ecdysteroids, total protein and lipids, suggesting interference with vitellogenesis.