Gonadotrophic effects of RH-5849, a non-steroidal ecdysone agonist on the rice moth Corcyra cephalonica St. (Lepidoptera: Galleriinae)

Abstract

In several areas throughout the world, the eggs of the fictitious host insect, Corcyra cephalonica, are used to produce multiple natural enemies, such as Trichogramma species, which are widely utilized for biological control of lepidopterous pests on diverse crops in more than 30 nations. The purpose of this study was to determine the efficacy of RH-5849, a non-steroidal ecdysone mimic, on the gonadotrophic parameters of the rice moth, Corcyra cephalonica. The separated II instar larva received the compound topically on the abdomen dorsum by means of Hamilton micro syringe in acetone. Five replicates (50 insect/replicate) were used per each dosage. Similar replicates were used for the control insects without any treatment. The mean number of eggs laid by a female moth was worked out on the basis of the total number of eggs laid by ten females. In a dose-dependent way, the sterility percentage was enhanced while the hatching percentage was decreased. The sterility indices were shown to be dose-dependent, according to current data. It should not be forgotten that the hatching percentages reversed this effectuation tendency (egg viability).