The effect of egg-surface treatment with ethanol on post-hatching survival and development of the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire)(Coleoptera: Curculionidae)

Abstract

A recent study showed that when eggs of the West Indian sweetpotato weevil (Euscepes postfasciatus) were submerged for five minutes in 70% ethanol, bacterial contamination was reduced in the larval artificial diet without decreasing hatchability. As an alternative to the ordinary egg-surface sterilization method (5 % formaldehyde 20 min submersion) in the artificial rearing of E. postfasciatus, we examined the utility of ethanol treatment of the weevil eggs in terms of post-hatching survival and development. We used survival rate (from egg hatching to adult eclosion). adult sex ratio, development time (from egg to adult), and body size represented by left elytra length as parameters for the survival and development of E. postfasciatus. Parameters measured in the present study did not vary significantly between the 70% ethanol-5 min and the 5% formaldehyde-20 min treatments. We conclude that ethanol can be used as an alternative sterilizing agent to formaldehyde for E. postfasciatus eggs in the artificial rearing of the species.