Location: Subtropical Horticulture Research2012 Annual Report
1a. Objectives (from AD-416):
The long-term objective of this project is to develop trapping and control components and systems for integrated pest management of exotic pest insects in the Caribbean, Central and South America that pose a threat to U.S. agriculture.
1b. Approach (from AD-416):
Research will consist of field and laboratory studies to determine the life history, distribution and host range of exotic insect pests; to identify semiochemicals; and to conduct studies on the behavioral and physiological roles of semiochemicals on these pests and associated biocontrol organisms. Strategies will include development of attractant-based technologies and systems for detecting, delimiting and monitoring exotic pest insects, and for establishing and enhancing management programs for these insects.
3. Progress Report:
Bait station effectiveness and longevity. Several versions of bait stations for pest fruit flies were evaluated. Bait stations were placed in trees, exposed to ambient environmental conditions, periodically and tested for efficacy. There tended to be higher mortality for caribflies than for medflies, but all versions remained effective for at least five months. Field tests were conducted in guava for population suppression of pest caribflies. Protein baits for West Indian fruit flies. As part of an ongoing collaboration with ARS-TARS, Mayagüez, Puerto Rico, field and laboratory studies were conducted to evaluate protein-based attractants for the West Indian fruit fly. Field tests included monitoring temporal and spatial distributions of fly populations in orchards and adjacent forest refuges. Laboratory studies included electroantennography (EAG) analyses to determine the effect of female age and reproductive status on olfactory response to ammonia and putrescine lures. Field tests of baits for pest drosophilid fruit flies. Field tests are ongoing to test liquid baits as lures for pest drosophilid flies, including the spotted wing drosophila, the African fig fly and D. melanogaster in fruiting trees at SHRS. Baits include vinegar, wine, sugar alone and in combinations, as well as synthetic chemicals identified from those substances by SHRS scientists as well as by ARS collaborators. Behavior of male medflies in response to exposure to plant essential oils. Effect of essential oil concentration was tested in laboratory bioassays using sterile males. High concentrations of several oils were found to be toxic to males when they were tested in closed vials, indicating a fumigant effect. Males did not approach high concentrations of these essential oils in movement bioassays using olfactometers, but moved preferentially toward those oils when tested at lower concentrations. Host preferences of the redbay ambrosia beetle. As part of research to identify host-based attractants for the redbay ambrosia beetle (RAB), the vector of laurel wilt disease, comparative studies were expanded to evaluate species of Lauraceae that occur primarily outside of Florida. In collaboration with the USDA-Forest Service, field tests and laboratory bioassays were conducted with freshly-cut branches to determine relative attraction and boring behaviors (host recognition/acceptance) of RAB to California bay laurel, camphor tree, sassafras, and spicebush. Comparative analysis of wood volatiles from these tree species, in combination with data collected previously (from avocado, redbay, swampbay, silkbay, and lancewood) is being used to identify the specific chemicals responsible for attraction of female RAB. Evaluation of essential oils for attraction of RAB. Previous research by SHRS scientists indicated that the current RAB lure (manuka oil) has a short field life (2-3 wks) in Florida and is not competitive with host wood. Ongoing field tests are evaluating (1) additional plant essential oils for improved attraction of RAB, and (2) different formulations of manuka oil to increase the release rates of RAB attractants and to improve lure longevity.
1. Development of methods to facilitate identification of attractants for redbay ambrosia beetle. The redbay ambrosia beetle (RAB) vectors laurel wilt, a lethal disease of avocado and other trees in the Lauraceae. No RAB pheromones have been identified to date, and the current monitoring lure (manuka oil) is suboptimal due to rapid loss of attraction. Improved lures are critically needed for early detection of this invasive pest. ARS scientists at Miami, FL developed a novel method for collection of live RAB in the field. These RAB are behaviorally and physiologically in host-seeking mode, ideal for controlled laboratory evaluations of attractants. In addition, ARS scientists recently developed an electroantennography (EAG) technique suitable for recording responses from the minute antennae of RAB. This EAG method currently is being used to quantify RAB olfactory responses to volatiles from host wood, essential oils, and synthetic terpenoid chemicals. This information will be combined with behavioral responses obtained in laboratory bioassays to confirm identification of the specific chemicals used by RAB for host location, and will facilitate development of improved field lures for RAB.
Niogret, J., Kendra, P.E., Epsky, N.D., Heath, R.R. 2011. Comparative analysis of terpenoid emissions from Florida host trees of the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: scolytinae). Florida Entomologist. 94(4):1010-1017.