2013 Annual Report
1a.Objectives (from AD-416):
The broad objective of this project is to improve survey and control tactics for Cactoblastis cactorum (Lepidoptera: Pyraliade), an invasive cactus-feeding moth that has rapidly expanded its geographical range along both the Atlantic and Gulf of Mexico coasts, invaded the Yucatan Peninsula, Mexico, and threatens the Opuntia-based agriculture and ecosystems in the southwestern USA and Mexico.
Specific objectives of this project are to optimize trap efficiency and pheromone lure, to improve implementation of the Sterile Insect Technique (SIT), to develop knowledge of additional control tactics that can be integrated into the containment of this pest at the leading edge of its geographical range; and the eradication of this pest at point infestations that may occur beyond the leading edge.
1b.Approach (from AD-416):
The research and development approach will include: (1) conduct field studies to characterize factors affecting trap efficiency and to develop methods for trap calibration, (2) conduct laboratory and field trials to identify and evaluate additional sex pheromone components and pheromone blends for use as a trap lure, (3) conduct mark-release-recapture trials to evaluate the influence of storage and transportation protocols, release methodology, and release frequency on the competitiveness and dispersal ability of sterile moths, (4) evaluate the performance of filter colony and mass rearing protocols for improved sterile insect production, and (5) complete life table studies on C. cactorum and its natural enemies to identify mortality factors limiting population growth and to identify differences between the native and adventive ranges of the pest, and.
6)make collections and establish colonies of native NA cactus-feeding Lepidoptera for use in host specificity tests of exotic natural enemies.
This project is related to objectives 1 and 2 of the inhouse project: (1) Improve performance of the sterile insect technique (SIT) as an integrated control tactic against invasive and established lepidopteran pests by developing techniques that accurately measure field performance of released sterile moths and evaluating various laboratory and semi-field bioassays for their ability to predict field performance of sterile moths. (2) Advance the ability to integrate and monitor SIT in abatement/eradication programs against exotic/invasive Lepidoptera pests by developing methods and techniques to survey for the presence and density of both genders of target pests species, and to measure overflooding ratios and interaction of released sterile insects and wild insects; improving trapping and survey technology by developing calibrations that accurately predict pest population densitities, trap efficiency, and efficacy of early detection programs for exotic pests; and, evaluating various marking techniques for identifying irradiated, released, and sterile moths and their interaction with the wild population, and measuring invasive pest movement and dispersal.
The Argentine cactus moth, Cactoblastis cactorum, is an invasive insect from South America that poses a serious threat to native Opuntia cacti biodiversity and Opuntia-based industries in the southwestern USA and Mexico. Since the initial 1989 find of C. cactorum in Florida, the moth has spread along the Gulf and Atlantic Coasts and now occurs as far west as Louisiana. A combination of tactics has been successful at slowing the spread of this insect and eradicating outbreak populations on islands in Alabama, Mississippi, and Mexico as a result of joint efforts initiated in 2006 by USDA and SAGARPA scientists. However, the cactus moth continues to spread and current funding levels are inadequate to sustain the area-wide program necessary to stop the moth’s spread. Focus of the program is now being placed on developing new control technologies that offer sustainable management options to minimize the long term impacts of the moth on native desert ecosystems and commercial cactus production areas.
The primary tactics under development are biological control and the disruption of pheromone communication systems (adult and larval). Scientists from the USDA-ARS Crop Protection and Management Research Unit, Tifton, Georgia, in collaboration with scientists from USDA-ARS-CMAVE in Tallahassee, Florida, and FuEDEI (Fundación Para el Estudio de Especies Invasivas), Argentina, have initiated host specificity studies of a larval parasitoid of C. cactorum. These scientists also conducted field trials on a formulation of the synthetic C. cactorum sex pheromone as a mating disruptant, and observed that both mating and oviposition were significantly reduced in the pheromone-treated plots. In continued collaboration with scientists from SUNY, Cortland, New York, studies are ongoing to evaluate the efficacy of the trail-following pheromone in C. cactorum larvae to disrupt the gregarious behavior required to successfully attack Opuntia.