S1017: Improved Systems for Management of Economically-Important Arthropod Pests Attacking Pecan
Statement of Issues and Justification
Pecan (Carya illinoinensis (Wang.) K. Koch ) is the most economically-important native nut crop in the U.S. It provides annual farm gate revenues > $300 million to diverse producers; most with < 100 acres and some with > 1000 acres. Uncultivated native stands are managed in river valleys that empty into the Gulf of Mexico but also in vegetatively propagated and seedling orchards across the south-central U.S. Growers rely on arthropod pest management strategies that are developed through regional entomology research dispersed across the pecan growing region. Regional coordination increases the feasibility of completing multiple research projects. Pecans are produced in 18 states but only GA, AL, LA, TX, OK, KS, and NM conduct research to control pecan pests. However, regional cooperation among pecan entomologists has provided research-based strategies for pest management in all states by effectively pooling resources, coordinating research and testing new technologies. Success of the regional research project is measured by the creation of new pest management tools and successful adaptation of new technology into IPM strategies widely used by pecan producers.Improving systems to manage pecan arthropod pests requires regional research that includes: improved systems to monitor pests, improved control systems for pests and development of pest biocontrol systems. Technical feasibility to complete this research is high given past regional accomplishments. Non-renewal would negatively affect our stakeholders by diminishing collaborative research between regions and limiting opportunities for direct transfer of information between scientists. This replacement proposal is directly related to Goal 4 (Greater harmony between agriculture and the environment) Part F (Integrated pest management systems, including biologically-based tactics) of the SAAESD Programmatic Plan priority areas for multistate research activities.
Pecan production differs across states requiring validation of monitoring and control techniques at different locations. In improved southeastern orchards, the pecan weevil (PW), HSW, aphids, and kernel-feeding hemipterans are important pests and minimized pesticide sprays during the early season conserves beneficial insects. In improved western orchards, pecan nut casebearer (PNCB) and aphids are important pests but others, e.g., PW, are not established. Insecticides may be applied to southwestern orchards for early season PNCB control, mid-season for PNCB and August for PNCB plus aphids. Management of native groves emphasizes control of PW and PNCB; one early application for PNCB and 2-3 fall applications for PW.
Pecan pest management changed considerably in the past 5 yr due to improved monitoring and chemical controls. The Circle trap improved PW detection and spray application. Pheromone monitoring of PNCB, HSW, and Euschistus spp. stink bugs was refined. Development of pheromones may allow for mating disruption to manage lepidopteran pests. Advances in biocontrol were made against aphids, pecan leaf scorch mite and PW. Orchard IPM was advanced by testing and recommending reduced-risk insecticides targeting specific pests but conserving natural enemies. However, rising costs of monitoring and control demand optimized management strategies. Aphid and mite resurgence remains a problem when broad spectrum insecticides are used against nut pests. Thus, implementation of more economical, target-specific insecticides and biocontrol measures are needed.
Non-chemical control of PW is needed. Carbaryl sprays for PW are often amended an insecticide to prevent aphid and mite resurgence because carbaryl destroys their natural enemies. Alternative control tactics include: biocontrol with nematodes and fungi, early nut harvest, improved trapping, soil moisture control, host plant attractants and cultivars with low vulnerability to oviposition. Regional research efforts are needed to integrate such new tactics into an overall IPM strategy.
The importance of this research to agriculture is in innovation to improve pest controls that protect and conserve this important native tree nut crop. The value to science is in using basic research to solve practical problems. Basic chemistry elucidated insect pheromones now used to monitor pests. Basic ecology developed aphid population models, predatorprey interactions and energy budgets for pest populations. Basic entomology delineated trophic relations between aphids and aphidophaga, lepidopteran pests and parasitoids, and weevils and pathogens. Insect behavior research led to better trap designs and alternative control tactics.
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