A new area-wide pest control strategy using a pink bollworm, Pectinophora gossypiella (Saunders), (Lepidoptera: Gelechiidae), genetically transformed with a conditionally lethal gene is under development. Conditional lethality of several transgenic pink bollworm strains was demonstrated in a series of laboratory rearing experiments. Pink bollworm were transformed with genetic constructs using the RIDL technology (Release of Insects with a Dominant Lethal gene) for development of an autocidal biological control system.

The lethal construct is controlled by a tetracycline controlled transactivator protein (tTa), which in the absence of tetracycline, causes expression of lethality. Tetracycline (as chlortetracycline) is a normal part of the pink bollworm artificial diet, so a tTa system conditionally lethal strain of pink bollworm could be incorporated into the current mass-rearing system.

In tests of several independent lines, mortality of transgenic pink bollworm reared on artificial diet without chlortetracycline ranged from 43 to 100%. For current constructs, most of the mortality appears to occur at the prepupae stage. Future work will focus on the determination of stage specific mortality rates and to quantify the fitness and performance of transgenic strains in small scale artificial rearing systems.