The backcross sterility technique

The sterile insect technique (SIT) and the induced inherited (F1) sterility technique have been investigated for a number of lepidopterous pests, including the gypsy moths. Another technique, backcross sterility, which could potentially prove as or more useful for control of pest species has been developed for the control of only one lepidopteran species, Heliothis virescens. This genetic technique has several theoretical advantages over both SIT and the F1 sterility techniques. In contrast to F1 sterility, backcross sterility can persist indefinitely once introduced into a population. Because fertile females are continuously backcrossed to target males, the strain becomes increasingly genetically similar to the target species. The backcross strain should also be behaviorally similar to the target species and there are no radiation-induced effects on competitiveness.