Submitted to: International Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2003
Publication Date: 2/1/2004
Citation: Hight, S.D., Pemberton, R.W., Bloem, K.A., Bloem, S., Carpenter, J.E. 2003. Our changing perception of cactoblastis cactorum in north america, p. 349, In Proceedings of the XI International Symposium on Biological Control of Weeds. Symposium held in Canberra, Australia April 27-May 2, 2003. 2004. Interpretive Summary:
Technical Abstract: Control of prickly pear cacti, Opuntia spp. (Cactaceae), by the South American cactus moth, Cactoblastis cactorum (Pyralidae), is a classic example of successful weed biological control. Unfortunately, in 1989 C. cactorum was found in the Florida Keys feeding on endangered O. corallicola. The insect attacks all six native Florida opuntias. The insect was not introduced to Florida as a biological control agent but most likely as a Caribbean immigrant on ornamental cacti. Of major concern is the potential spread of C. cactorum to the opuntia-rich areas of the western U.S. and Mexico. This could have devastating effects on the landscape and biodiversity of this region. In addition, the forage and vegetable opuntia industries in Mexico will likely be severely impacted by this "pest". This study is addressing three objectives: 1) determine the current distribution and spread of C. cactorum in North America; 2) determine the potential impact of native natural enemies on the spread (and possible control) of C. cactorum; and 3) explore the potential of the inherited sterile insect technique (SIT) to control C. cactorum. The moth's range continues to expand and now reaches as far north as Charleston, SC along the Atlantic and the Florida Panhandle along the Gulf of Mexico. The moth is spreading most quickly on cacti along the coast. However, infestations noted in the interior are becoming more common. Parasitoids (Tachinidae, Ichneumonidae) found attacking the native cactus moth, Melitara prodenialis (Pyralidae), were also found attacking C. cactorum but at lower rates. Irradiation studies have determined the dose at which C. cactorum males are 100% sterile and the deleterious effects inherited by the F1 generation minimized. An SIT program may be useful controlling C. cactorum along its leading edge to limit geographical range, to eradicate isolated populations far in front of the leading edge, or as an abatement program to protect rare and endangered Opuntia spp.