Scientists deploy sterile moths to curb invasive cactus moth threatening native cacti

The South American cactus moth, first brought to Nevis in 1957 to curb invasive prickly pear, later spread throughout the Caribbean and arrived in the Florida Keys by 1989, where it began feeding on native cactus species such as Opuntia, Nopalea, Cylindropuntia and Consolea. Damage occurs when females lay eggs on cactus pads, and the hatching larvae tunnel inside, eventually killing the plant. To counter this, the USDA’s Agricultural Research Service, led by entomologist James Carpenter, is employing the sterile insect technique: males are reared on an artificial diet, irradiated to become sterile, and released to outcompete wild males.

The program is being evaluated at three sites—Dauphin Island, Alabama (with combined sterile releases and sanitation), Okaloosa Island, Florida (sanitation only), and St. George Island, Florida (no treatment). Sanitation involves removing infested pads and egg sticks. Preliminary data from Dauphin Island indicate the moth population has been reduced to almost undetectable levels, suggesting the approach could protect native cacti and the ecosystems they support.