Location: Insect Behavior and Biocontrol Research
2022 Annual Report
Objectives
1. Develop strategies for optimal use of biological control agents against invasive weeds such as air potato and Chinese tallow tree based on research that improves our understanding of factors that determine weed abundance, including biotic and abiotic elements and climatic region.
1.A. Determine the role of native natural enemies attacking a biological control agent (Caloptilia triadicae) in its introduced range.
1.B. Determine presence and importance of air potato leaf beetle chemical communication pathways to improve air potato biological control.
2. Develop and refine biologically-based control strategies for invasive insects such as the Argentine cactus moth, Harrisia cactus mealybug, and Old World bollworm, focusing on the use of parasitoids and disrupting pheromone cues.
2.A. Determine release factors that increase successful establishment of the parasitoid Apanteles opuntiarum against the Argentine cactus moth.
2.B. Determine the effectiveness of released control agents Anagyrus cachamai and/or A. lapachosus to control the Harrisia cactus mealybug (HCM) in Puerto Rico.
2.C. Determine the effectiveness of disrupting pheromone communication between gregarious cactus moth larvae as a sustainable management tactic for this pest in commercial cactus production areas.
2.D. Determine whether parasitoids that attack native Helicoverpa zea will also be successful against the potentially invasive Helicoverpa armigera.
3. Develop sustainable management strategies such as “push-pull” technology for controlling invasive whiteflies in vegetable production using naturally repellent plants, plant chemicals, trap plants, and green leaf volatiles together with natural enemy refuge plants.
3.A. Identify companion plants, products and chemical compounds that a) repel whiteflies and determine their efficacy in limiting pest dispersal into crops (“push” factors), as well as b) identify plants and products capable of attracting whiteflies into trap crops to facilitate control (“pull” factors).
3.B. Evaluate companion or refuge plants that “attract and reward” important whitefly predators.
3.C. Develop an integrated cropping system combining “push-pull” crops or plant products with natural enemy refuges for sustainable biologically-based control of whiteflies.
Approach
Invasive insect pests and weeds are among the most serious problems facing agricultural and natural ecosystems throughout the United States. This project plan describes research to improve implementation of biologically based tactics for non-pesticide management of insect pests and weeds through a better understanding of the pest species’ biology and interactions with host plants and natural enemies, as well as development of optimized approaches, technologies and strategies. One area of research will address improvement of techniques to enhance release success, establishment and impact of biological control insect species against invasive weed species such as the air potato and Chinese tallow tree. Another area of research focuses on the development of an integrated cropping system for control of whiteflies in vegetable crop systems using ‘push’ components consisting of naturally repellent plants or plant compounds, in conjunction with ‘pull’ components that consist of trap crops, complemented by refuge plants to attract and reward natural enemies. Finally, the use of host specific parasitoids for the protection of native cacti from the invasive Argentine cactus moth and the Harrisia cactus mealybug, and protection of crops from the potentially invasive Old World bollworm, will be studied. Therefore, the plan is expected to serve several stakeholders and customers, including researchers at land grant institutions, government and non-governmental organizations, growers, ranchers and commodity groups, and small-scale farmers and organic producers. The outcomes of this research project will improve the sustainability of agricultural production, reduce reliance on pesticides and reduce the environmental degradation caused by invasive pest species.
Progress Report
Progress was made by ARS researchers in Tallahassee, Florida, on objectives, all of which fall under National Program 304, Component 2, Weeds and Component 3, Insects and Mites. For Component 2, progress on this project focuses on Problem Statements B, biological control and ecosystem research, and C, integrated approaches to weed management. For Component 3, progress on this project focuses on Problem Statements A, early detection, prediction and monitoring of beneficial and pest arthropods, B, develop new or improved management tools and knowledge to control arthropod pests, and C, integrate management strategies to control arthropod pests. Under Objective 1, progress was made with field surveys of parasitoids and laboratory insect behavior assays for Subobjective 1a. The identity, diversity, abundance, and activity of parasitoids attacking the tallow tree biological control agent, Caloptilia triadicae, were recorded from field surveys. For Subobjective 1b, behavioral responses of air potato leaf beetles to volatiles from air potato leaf volatiles were tested in olfactometers in the laboratory. These volatiles analyzed with GC-MS revealed identification of several primary volatile components. This progress will allow for the development of strategies to optimize biological control, either through reduction of parasitism from native insects to biological control agents or through the manipulation of biological control agents with semiochemicals to increase control potential of the agent. Progress has also been achieved on Objective 2, Subobjectives 2a-2c. For Subobjective 2a, release permits of a natural enemy wasp have been delayed, significantly postponing progress. However, collaborations are ongoing, and personnel are actively working to obtain the release permitting back on schedule. Once approved, this biological control agent will become an integral part of pest management strategies for Argentine cactus moth control. Additionally, for Subobjective 2b, permitting is ongoing for the approval of parasitoids to control Harrisia cactus mealybug. While permits are being considered, pre-release conditions of the environment are being recorded to determine the impacts of the agent once the agent is approved and established. Subobjective 2c is also progressing through the active development of methodologies to determine the response of Argentine cactus moth to disruption techniques with its aggregation pheromone. Because of travel restrictions to Puerto Rico, Subobjective 2d was not completed. However, further sampling for Helicoverpa zea parasitoids was continued in several host plant habitats in the southeastern U.S. Under Objective 3, Subobjective 3a, progress was made by discovering that a component of green leaf volatiles, leaf acetates, were more attractive than leaf alcohols to whiteflies. This discovery will help identify components to be used as the “pull” tactic in a “push-pull” management system. For Subobjective 3b, study of the attraction of predators was done through the use of companion plants such as sweet alyssum, marigold, and African basil and a commercial beneficial attractant in tomatoes, leafy greens and strawberry crops in high tunnels. The main beneficial insect predators collected throughout the season were minute pirate bugs, big-eyed bugs and green lacewings, all excellent predators of whiteflies. For Subobjective 3c, research methods developed included testing the above companion flowering plants combined with the commercial beneficial attractant. Intercropping may involve alternate planting of the target crop and companion plant within the same row or every two rows in a randomized block design.
Accomplishments
1. Development of a flowering phenology model for Chinese tallow. The development of a biological control program for the highly invasive Chinese tallow tree in the southeastern United States is ongoing, however, concerns over the biological control program have been expressed by the beekeeping industry. Chinese tallow is claimed to be a critical, irreplaceable nectar plant for migratory beekeepers. To better understand the importance of Chinese tallow for honey bee forage, ARS researchers in Tallahassee, Florida, developed a flowering phenology model. This model has generated new information on the onset, offset, and duration of Chinese tallow flowering, correcting misconceptions from the literature and providing new information for beekeepers. This new information could prove to be critical in addressing the concerns from the beekeeping industry that is currently delaying the implementation of a biological control program for Chinese tallow.
2. Eco-based pest management for organic vegetables in high tunnel greenhouses. High tunnel production of vegetables is a promising approach used widely for production, however pest management under these conditions can be challenging. ARS researchers in Tallahassee, Florida, used a dual strategy of using “push-pull” technology and companion planting in high tunnels to control insect pests in the high value organic crops of tomato, leafy greens and strawberry in north Florida. The “push” component consisted of repellent plants such as 2 varieties of mustard (var. giant red, caliente) and arugula (var. nemat). The “pull” component involved green leaf volatile chemicals and a commercial predator lure. A leaf -emitted acetate, in particular, was a promising attractant for the sweetpotato whitefly in laboratory olfactometer tests with stronger responses than to the green leaf alcohols, generally known as attractants. In the high tunnels, a commercial beneficial insect attractant was evaluated and a relatively low population of insect pests such as whiteflies, thrips and aphids were present throughout the growing season. The main beneficial natural enemies collected were the whitefly parasitoids. The dual strategy of the “push-pull” technology and companion planting may be a low-cost, sustainable eco-based pest management tool to control insect pests in high tunnels.
Review Publications
Almarinez, B.M., Fadri, M.A., Lasina, R., Tavera, M.A., Carvajal, T.M., Watanabe, K., Legaspi, J.C., Amalin, D.M. 2021. A Bioclimate-based maximum entropy model for Comperiella calauanica Barrion, Almarinez & Amalin (Hymenoptera: Encyrtidae) in the Philippines. Insects. 12(1), Article 26. https://doi.org/10.3390/insects12010026.
Gaffke, A.M., Alborn, H.T., Dudley, T.L., Bean, D.W. 2021. Using chemical ecology to enhance weed biological control. Insects. 8:695. https://doi.org/10.3390/insects12080695.
Bowers, K., Hight, S.D., Wheeler, G.S., Minteer-Killian, C. 2022. Ecological host range of Pseudophilothrips ichini (Thysanoptera: Phlaeothripidae), a biological control agent of Brazilian peppertree. Biological Control. 172. https://doi.org/10.1016/j.biocontrol.2022.104976.
Francis, N., Kanga, L.H., Mannion, C., Haseeb, M., Ananga, A., Legaspi, J.C. 2022. First report on voracity and feeding preference of predatory beetle, Thalassa montezumae (Coleoptera: Coccinellidae) on croton scale, Phalacrococcus howertoni (Hemiptera: Coccidae). Agriculture Journal. 12(7). https://doi.org/10.3390/agriculture12070990.
Poveda-Martinez, D., Varone, L., Corona, M., Hight, S., Logarzo, G., Hasson, E. 2021. Spatial and host related genomic variation in partially sympatric cactophagous moth species. Molecular Ecology. 31(1):356-371. https://doi.org/10.1111/mec.16232.
