Backcross Progeny from Interspecific Hybrids of Heliothis subflexa × H. virescens : Physiological Diapause, Winter Survival and Infusion into Natural H. virescens Populations

Backcross (BC) progeny resulting from interspecific hybridization of H. subflexa (Guenee) females × H. virescens (F.) males and backcrossed to H. virescens males eight times (BC8) entered physiological diapause, survived the winter, and emerged the following spring at the same time as H. virescens . Heliothis subflexa moths from diapausing pupae also emerged at ca. the same time as H. virescens . Diapausing BC and H. virescens pupae reacted similarly to all treatments with low temperatures in the laboratory. Diapausing BC and H. virescens pupae, in the absence of other factors such as free water, etc., withstood extremely low temperatures in the laboratory for short periods of time. Subsequent Be moth generations were collected after an initial release and also the following spring during the spring emergence period of H. virescens . When infused into the natural H. virescens population, BC moths carrying the sterile male trait entered diapause, survived the winter, and emerged the following spring.