Location: Insect Behavior and Biocontrol Research2012 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:
Objective 1: Two field trials were conducted, in collaboration with scientists from the University of Florida and Glades Crop Care to assess the utility of push-pull strategies for the managment of western flower thrips and tomato spotted wilt virus in tomato and pepper crops. Because of their attractiveness to pest thrips, sunflowers and Bidens alba were used as plants to attract thrips away from target cash crops. These plants are also attractive to competitor thrips and predators of western flower thrips. Ultraviolet reflective mulches and kaolin, a clay-like material that can be sprayed on crop plants, were used as repellents to push thrips away from target cash crops. The results to date indicate that these push and pull tactics may be beneficial in thrips managment programs by deterring pest thrips and enhancing local populations of non-pest competitor thrips and predatory insects that suppress western flower thrips populations. Objective 2: The ficus whitefly is an emerging pest of ornamental ficus in Florida. To better characterize the potential for biological control of the ficus whitefly, collaborative research with scientists from the University of Florida is being conducted with biological control agents already established in Florida. Predation rates of the coccinellid Delphastus catalinae on different stages of the ficus whitefly have been analyzed. Both adult and larvae of Delphastus preyed on substantially more ficus whitefly eggs than on small or large nymphs. Objective 3: Significant progress was made to develop biological control strategies for the invasive Argentine cactus moth. In collaboration with Argentine scientists, a parasitic wasp is being studied for its host specificity and suitability as a classical biological control agent. A wasp colony is being maintained for future shipment to the U.S., and protocols have been developed for rearing the wasp and for testing non-target caterpillars as potential hosts. Host range testing on other Argentine cactus-feeding moth species has proven the wasp to be host specific. Morphological and molecular studies have determined that the wasp is new to science and a description of the species has been prepared. Once a permit is obtained to bring the wasp into USA quarantine, continued host range testing will be conducted on North American cactus-feeding moths. If continued research proves the wasp to be an effective biological control agent, it would represent a self-perpetuating control option and practical approach to protecting native prickly pear cactus in the desert Southwest and Mexico.
Manrique, V., Diaz, R., Hight, S.D., Overholt, W.A. 2011. Evaluation of mortality factors using life table analysis of Gratiana boliviana, a biological control agent of tropical soda apple in Florida. Biological Control. 59(3):354-360.