Technical Abstract: The most successful classical biocontrol of weeds program has been the control of invasive prickly-pears (Opuntia spp.) by the Argentine cactus moth Cactoblastis cactorum. However, the moth has invaded North America and its ability to control its host plant raises concerns for the safety and survival of the many important Opuntia spp. in North America. A variety of tools and tactics were developed to study and control C. cactorum. A survey tool was developed to identify the presence of the moth. Insecticide trials were conducted. In support of a Sterile Insect Technique (SIT), studies were conducted on mass rearing, radiation biology, overflooding ratios, transport - cold storage - release techniques, and sanitation efforts. Mating of C. cactorum takes place within the hour before sunrise. Female sex pheromone components were characterized, and a sticky-bottom wing trap baited with a synthetic female pheromone lure was developed as the survey tool. This trap identified three generations/year in the USA across a large latitudinal gradient. Three insecticides effectively killed eggs and neonate larvae. A radiation dose of 200 Gy is sufficient to fully sterilize females. Wing traps are a useful survey tool to identify when and where wild insects are present and where to deploy the SIT. Sanitation and SIT are complimentary control tactics. Sanitation is effective in high populations and SIT is effective in low populations. Insecticides may be useful to control C. cactorum if restrictions are placed on the movement of Opuntia nursery stock.