Cactoblastis cactorum (Berg) 1885
Cactus moth threatens Mexico and the American Southwest
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Name: Cactoblastis cactorum (Berg) 1885
Animalia: Arthropoda: Insecta: Lepidoptera: Pyralidae
Common Names: Cactus moth; prickly pear moth
The cactus moth, native to South America, was discovered in the Florida Keys in 1989, arriving either through natural spread or with imported cactus shipments from the Caribbean. In Florida, the moth is now present throughout the Keys and along both coasts. Cactoblastis cactorum feeds exclusively on species of Opuntia (prickly pear cacti) and poses a potential threat to native Opuntia-rich regions such as Mexico and the American Southwest. Mexico is particularly concerned because it currently imports prickly pear fruits from Florida, a potential pathway for the moth.
Issues of Concern:
This moth has been used as a very successful and rapid biological control agent in Australia, Hawaii, India, South Africa, and the Caribbean to eradicate exotic and/or weedy species of Opuntia. Because of its effectiveness, the moth threatens native and endangered species of North American Opuntia by weakening and/or killing younger plants, thereby affecting long-term species recruitment. Prickly pear cactus is particularly important in the American Southwest and Mexico, where their fruit and young vegetative parts are a staple part of the human population's diet and where chopped plants serve as an alternate food for cattle in times of drought. In South Africa, the growth of spineless Opuntia's, valued as cattle fodder, was significantly reduced by C. cactorum.
Pathways: The cactus moth utilizes Opuntia's important in the nursery trade, and is often intercepted in commercial imports of vegetative material intended for propagation; the moth may also travel in consumptive articles.
Hosts: Species in the genus Opuntia, including O. aurantiaca, O. dillenii, O. ficus-indica, O. inermis, O. stricta, and O. triacantha.
Africa (South Africa, Tanzania); Australia; South America (Argentina, Brazil, Paraguay, Uruguay); United States (Florida, Hawaii); West Indies (Antigua, Bahamas, Dominican Republic, Grand Cayman, Haiti, Lesser Antilles, Montserrat, Nevis, St. Kitts, Trinidad, US Virgin Islands).
The eggs are laid in linear masses called "sticks"; the hatched larvae then cluster on the surface of a pad near the base of the egg stick. The larvae cover themselves with a fine silken web and proceed to chew one or more holes through the epidermis. When the interior is consumed or begins to rot, the larvae vacate the pad and migrate to a new one. As the moth enters the pupal stage, the mature larvae construct cocoons that can be found in the soil litter, beneath logs and rocks, as well as in crevices on lower parts of the plants.
Habeck, D.H., and F.D. Bennett. 1990. Cactoblastis cactorum Berg, a phycitine new to Florida. Fla. Dept. Agric. & Consumer Serv. Division of Plant Industries, Entomology Circular 333.
Johnson, D.M, and P.D. Stiling. 1998. Distribution and dispersal of Cactoblastis cactorum (Lepidoptera: Pyralidae), an exotic Opuntia-feeding moth, in Florida. Florida Entomologist 81(1): 12-22.
Pemberton, R.W. 1995. Cactoblastis cactorum in the United States: an immigrant biological control agent or an introduction of the nursery industry? American Entomologist 41: 230-232.