Location: Insect Behavior and Biocontrol Research2011 Annual Report
1a. Objectives (from AD-416)
1. Develop habitat manipulation strategies as components of IPM programs for polyphagous pests through behavioral and ecological studies of their interactions with host plants and natural enemies. 2. Develop “push – pull” strategies for whitefly management that integrate plant-based pest repellents and natural enemy attractants. 3. Develop and refine control strategies for invasive species infesting non-traditional agricultural settings, in particular the Argentine cactus moth and Chinese tallow.
1b. Approach (from AD-416)
We will determine how polyphagous thrips select and utilize host plants, and how these responses may be manipulated to reduce pest thrips within crops. We will use a model system consisting of tomato and 4 potential trap crops and varying fertilization regimes to test thrips responses to host plant quality as a means to develop trap cropping systems. Systematic surveys of weeds will be used to assess their role as reservoirs in the spread of thrips-vectored viruses. Host plants effects on acquisition and transmission of Tomato Spotted Wilt Virus (TSWV) by thrips will be tested by using various plants as acquisition sources and inoculation targets. Tropical soda apple will be used as a model system to determine how biological control of an invasive weed may reduce the spread of TSWV. Field studies will be used to determine if the presence of the banker plants can increases predation on thrips. Push-pull strategies for the management of whiteflies will be developed. Certain plants and extracts from them will be tested in the field and lab to determine if they can repel whiteflies from target crops. Bioassays of other plants will be used to identify those that are good reservoirs for predators of whiteflies. Combinations of repellent plants and banker plants for predators will be studied to optimize push-pull strategies for whitefly management. The sterile insect technique for management of invasive lepidopteran pests will be improved by development of bioassays that measure field performance of sterile moths. Lab bioassays will then be developed as proxy measures for field performance bioassays to gauge sterile insect performance. Existing pheromone trapping for monitoring cactus moth populations will be improved through calibrating captures with population size. Life table studies will be conducted in the cactus moth’s invaded range to identify stages most amenable for biological control. Additional biological control will be assessed by testing non target risks of Trichogramma pretiosum, a candidate for inundative releases. Population dynamic studies of Chinese tallow will be conducted to identify what types of biological control agents may have the greatest impact on the weed.
3. Progress Report
We continued research with colleagues from the U.S. Horticultural Research Laboratory & Glades Crop Care to characterize thrips species in the southern USA that are capable of transmitting Groundnut ringspot virus, which was recently identified by team members as present in Florida. Results to date indicate that at least two invasive thrips species present in Florida are capable of transmitting this virus. Research continues into adapting Integrated Pest Management (IPM) programs to address this new pest threat. Two field trials were conducted, in collaboration with the University of Florida Glades Crop Care to assess the push-pull strategies for the management of thrips in tomato and pepper crops. Because of their attractiveness to pest thrips, sunflowers and Bidens alba were used as plants to “pull” thrips from target crops. Ultraviolet reflective mulches and kaolin, a clay-like material that was sprayed on plants, were used to “push” thrips away from the target crops. First year results indicate that these tactics may be beneficial in thrips management programs. We made progress in the development of plants and plant-based repellents for the management of the sweetpotato whitefly, a major insect pest of important vegetable and horticultural crops that is difficult to manage with insecticides. Choice test results showed that giant red mustard is repellent to whitefly adults and that mustard oil applied to other plants can reduce whitefly oviposition. Significant progress was made to increase the success of the sterile insect technique (SIT) used against the invasive cactus moth, and to develop additional controls for this moth. Quality control tests were developed that measured differences in sterile moths before and after they were released into the field to control the cactus moth. After changes were made in the rearing procedures, the quality control tests revealed improvement in the quality of sterile insects.Higher quality sterile moths compete against wild catus moths for mates, and when sterile males mate with a wild female, her eggs fail to develop. Improvement to the ARS-developed cactus moth pheromone was studied in field tests on new pheromone blends. Initial tests indicated that a two component blend catches more cactus moths and fewer non-target moths than the currently used blend. Additional field trials are planned to determine the most effective ratio of the two blends. Two biological control agents of the cactus moth were studied; a wasp in Florida that parasitizes eggs and a wasp in Argentina that parasitizes caterpillars. These wasps have been used in other programs to control moth pests by mass rearing the wasps and releasing them. If the tiny egg-attacking wasps were used in a program to control the cactus moth, our studies indicated that honey should be fed to mass reared wasps, young (2-3 day old) mated wasps should be released, and releases timed to coincide with newly laid cactus moth eggs. Research continues in Argentina on the wasp that parasitizes cactus moth catepillars. The wasp will be studied in a Florida quarantine to evaluate its risk to North American catepillars.
1. Insect Pest Managment for thrips and tospoviruses in tomato crops. Thrips and thrips-vectored viruses are among the most serious pests of vegetable, ornamental, and agronomic crops in Florida. Therefore, scientists from the Center for Medical, Agricultural and Veterinary Entomology, Tallahassee, FL, and the University of Florida have used their collaborative research findings to develop a set of guidelines for growers to effectively manage thrips and thrips-transmitted viruses in tomato crops. These management guidelines are built around the use of realistic economic thresholds, scouting and identification of thrips species, conservation of non-pest thrips that outcompete pest species, ultraviolet reflective mulch, and the avoidance of insecticides that induce western flower thrips populations, and vertical integration of management of western flower thrips with other pests, including whiteflies and Lepidopteran pests. These recommendations are being adopted by growers, leading to reduced pest pressure with lower insecticide use and improved yields.
Sobhy, I.S., Sarhan, A.A., Shoukry, A.A., El-Kady, G.A., Mandour, N.S., Reitz, S.R. 2010. Development, consumption rates and reproductive biology of Orius albidipennis reared on various prey. Biocontrol. 55:753-765.