Location: Insect Behavior and Biocontrol Research
2023 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 in National Program 304, Component 2, Weeds and Component 3, Insects and Mites. For Component 2, research was conducted on Problem Statements B, biological control and ecosystem research; and C, integrated approaches to weed management. For Component 3, progress related to 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. For Objective 1 Subobjective 1A, surveys of parasitoids from Chinese tallow trees, Caloptilia triadicae, were conducted with an overall parasitism level of 10%. Five species were identified parasitizing C. triadicae during the study, with 50% of the parasitism being attributed to one Hymenopteran species. For Subobjective 1B, behavior assays of air potato beetles revealed increased attraction of air potato leaf beetles to plants damaged by conspecifics. Adult beetles were attracted more to both adult-damaged plants and larval-damaged plants, compared to undamaged plants. Additionally, the air potato leaf beetle was attracted to damage from other air potato biocontrol agents and damage from generalist herbivores. These results for Objective 1 will allow for the development of strategies to optimize biological control, either through increased understanding of parasitism from native insects to biological control agents or through the manipulation of biological control agents with semiochemicals. Research has also progressed on Objective 2. Progress on use of exotic parasitoids for the Argentine cactus moth and Harrisia cactus mealybug was delayed due to permitting issues. For Subobjective 2C, colonies of the Argentine cactus moth were established, and suitable host plants collected and are in use for on-going research on the efficacy of the Argentine cactus moth trail pheromone to disrupt the life cycle of the moth. Comparisons include Opuntia stricta (native) as well as Opuntia ficus-indica (commercial) cacti. Research for Subobjective 2D was limited due to very low populations of Helicoverpa zea parasitoids, the loss of H. armigera colony in Puerto Rico and difficulty in locating H. armigera in Puerto Rico. Under Objective 3 Subobjective 3A, progress was made by discovering that a component of green leaf volatiles, the leaf acetates, were significantly attractive to sweet potato whiteflies with lower attraction also seen to leaf alcohols. Green leaf volatiles may be useful for monitoring and trapping whiteflies and as a tool in controlling this major insect pest in vegetable crops. For Subobjective 3B, attraction of predators to companion plants such as sweet alyssum, marigold, and African basil was confirmed in leafy greens and strawberry crops in high tunnel greenhouses. Evaluations of additional companion plants such as a commercial mix of flowering plants and basil near a winter squash, zucchini, and cantaloupe field crop are on-going. For Subobjective 3C, research methods were developed for larger-scale testing of “push-pull” technology and companion flowering plants. Components include intercropping by planting different patterns and different ratios of repellent, trap, and companion plants in a randomized block design.
Accomplishments
1. Identification of semiochemicals causing air potato beetle aggregations. Air potato is a non-native invasive weed spreading across the southeastern United States, and because of its invasive nature, the air potato leaf beetle was introduced to help control this plant. The air potato beetle has been very successful at controlling the plant; however, some patches of the weed seem to be able to avoid detection and feeding and thus control from the beetle. Studies conducted by an ARS researcher in Tallahassee, Florida, on the plant indicated that when the beetles feed on it, they cause the plant to release highly attractive odors, ultimately calling in more beetles and causing more damage to the plant. Additionally, it was discovered that feeding from the beetle causes significant changes to the plant’s metabolism, which impacts its ability to regrow after damage and reproduce. The odors that caused this attraction were identified and are being developed into lures to actively 'herd' beetles to the plants, resulting in better control of this invasive weed. University stakeholders are requesting lures to test and deploy to facilitate monitoring and manipulation of populations in the field.
2. Formation of Chinese tallow working group. The Chinese Tallow tree is a subtropical species that has invaded a wide range of ecological habitats throughout the southeastern US. Management involves and impacts a wide range of users and agencies with many concerns about the prolonged presence or removal from habitats. In collaboration with Barataria-Terrebonne National Estuary Program, Louisiana State University and an ARS researcher in Tallahassee, Florida, a Chinese tallow working group was created to facilitate discussion between the diverse group of stakeholders and land managers interested in the management of this weed and the stakeholder interested in preserving Chinese tallow populations. This working group is seeking to provide scientifically based, empirical data to regulatory agencies, to provide the latest science about tallow impact and management, and to explore needs to address the recovery of invaded habitats. Additionally, the working group is developing key messaging on integrated habitat management and how several disciplines and/or stakeholders can cooperate for better natural habitat management against tallow infestations in the southeastern United States.
3. Sweetpotato whitefly attraction to green leaf volatiles. Sweetpotato whitefly, Bemisia tabaci, is a major insect pest of vegetables in the field and in high tunnel greenhouse production. For organic production, a promising approach investigated by an ARS researcher in Tallahassee, Florida, is the use of natural “push” and “pull” system where whiteflies are pushed away from vegetables and pulled towards plants containing natural enemies. As part of the “pull” component, the attraction of whiteflies to the green leaf volatiles leaf acetates and leaf alcohols were assessed in Y-tube olfactometer with stronger attraction to leaf acetates and moderate attraction to leaf alcohols. Attraction to these green leaf volatiles can be used as a component in a push-pull system or a basis for monitoring and trapping whiteflies.
Review Publications
Legaspi, J.C. 2022. Life history of Euthyrhynchus floridanus (L.) (Hemiptera: Pentatomidae). Subtropical Agriculture and Environments. 73:41-46.
Perier, J.D., Haseeb, M., Solis, D., Kanga, L.H., Legaspi, J.C. 2023. Estimating the cost of production of two pentatomids and one braconid for the biocontrol of Spodoptera frugiperda (Lepidoptera: Noctuidae) in maize fields in Florida. Insects. 14(2):169. https://doi.org/10.3390/insects14020169.
Zimba, K., Read, Q.D., Hasseb, M., Meagher Jr, R.L., Legaspi, J.C. 2022. Potential of silicon to improve biological control of fall armyworm, Spodoptera frugiperda, on maize. Agriculture Journal. 12(9):1432. https://doi.org/10.90/agriculture12091432.
Amalin, D.M., Arcelo, M., Almarinez, B.J., Castillo, R.C., Legaspi, J.C., Tavera, M.A., Janairo, J.B., Zhang, A. 2023. Field evaluation of the sex pheromone of the cacao pod borer, Conopomorpha cramerella (Snellen) in the Philippines. Journal of Asia-Pacific Entomology. https://doi.org/10.3389/fagro.2023.1165299.
Gaffke, A.M., Dudley, T.L., Bean, D.W., Drus, G.M., Johnson, M.J., Knutson, A.E., Weaver, D.K., Sing, S.E., Orr, B.K., Thompson, D.C. 2022. Tamarix biocontrol in North America. Book Chapter. 329-355.
Sing, S.E., Tosevski, I., Ward, S.M., Weaver, D.K., Gaffke, A.M. 2022. Biological control of invasive Linaria spp. in the Western United States. Book Chapter. 294-311.
Thomas, G., Rusman, Q., Morrison III, W.R., Magalhaes, D.M., Dowell, J.A., Ngumbi, E., Osei-Owusu, J., Kansman, J., Gaffke, A.M., Jayanthi, K., Kim, S., Tabanca, N. 2023. Deciphering plant-insect-microorganism signals for sustainable crop production. Biomolecules EISSN 2218-273X. 13(6):997. https://doi.org/10.3390/biom13060997.
Diedrick, W., Kanga, L.H., Haseeb, M., Srivastava, M., Legaspi, J.C. 2022. Population dynamics and parasitism of the kudzu bug, Megacopta cribraria, by egg parasitoids, Paratelenomus saccharalis in southeastern USA. Agriculture Journal. 13(1):13. https://doi.org/10.3390/agriculture13010013.
Jermaine, P.D., Haseeb, M., Kanga, L.H., Meagher Jr, R.L., Legaspi, J.C. 2022. Intraguild interactions of three biological control agents of the fall armyworm Spodoptera frugiperda (JE Smith) in Florida. Insects. 13(9):815. https://doi.org/10.3390/insects13090815.
Gaffke, A.M., Shapiro-Ilan, D., Alborn, H.T. 2022. Deadly scents: Exposure to plant volatiles increases mortality of entomopathogenic nematodes during infection. Frontiers in Physiology. 13:978359. https://doi.org/10.3389/fphys.2022.978359.
Griesheimer, J.L., Gaffke, A.M., Minteer, C., Mass, J.L., Hight, S., Martini, X. 2023. Attraction of the air potato leaf beetle, Lilioceris cheni (Coleoptera: Chrysomelidae) to leaf volatiles of the air potato, Dioscorea bulbifera. Journal of Chemical Ecology. https://doi.org/10.1007/s10886-023-01436-z.
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). Journal of Agriculture. 12(7):990. https://doi.org/10.3390/agriculture12070990.
