The primary screwworm Cochliomyia hominivorax is a devastating obligate parasite of livestock in South America. The joint US-Panamanian facility in Pacora, Panama produces millions of sterile flies weekly that are released along the Colombian border to prevent screwworm from re-establishing in Panama. To improve the efficiency of genetic suppression we are developing novel methods for producing only sterile male flies including conditional female lethal and female transformation strains. The genetic systems are first developed in Raleigh and evaluated in close relatives of the screwworm such as the secondary screwworm, which is native to North Carolina. Promising genetic systems are shipped to Panama for evaluation in primary screwworm.