Diapause of the southwestern corn borer,Diatraea grandiosellaDyar (Lepidoptera, Pyralidae): effects of a juvenile hormone mimic

Abstract

AbstractTopical applications of a juvenile hormone (JH) mimic induced and prolonged the mature larval diapause of the southwestern corn borer,Diatraea grandiosellaDyar. The onset of this diapause is marked by an ecdysis from a spotted to an immaculate morph. A high percentage of spotted non-diapause larvae treated with a single dose of a JH mimic moulted into the immaculate morph and became dormant. Similar treatments of diapause larvae led to a reversion to the spotted morph, but the larvae remained dormant. These results imply that diapause larvae contain an intermediate JH titre. A use for JH mimics in disrupting the seasonal phenology of pest insects with larval dormancies is suggested.