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United States Department of Agriculture

Agricultural Research Service

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Location: Southern Horticultural Research

2012 Annual Report

1a. Objectives (from AD-416):
Develop strategies for controlling insects that are problematic in nursery settings (e.g., fire ants, tree borers, Japanese beetles) in the southeastern United States and/or develop strategies for implementation of low-residual pesticides.

1b. Approach (from AD-416):
1) Elucidate the physiological chemical ecology of fire ants and other insects that are problematic in greenhouses, container pads, fields, and other environs suitable for growing ornamental crops. 2) Develop spray strategies to best use pesticides (specifically fungicides) that have low residual acitivity.

3. Progress Report:
To establish new, non-chemical control methods for fire ant (FA) in Tennessee, FA workers were collected and shipped to USDA-APHIS for exposure to two new types of FA parasite flies. Parasitized ants were re-released in the wild in Sept 2011. One of the parasites was not recovered during 2011 at the Sequatchie county release site. Franklin county release will not be evaluated until summer 2012. This parasite is reported to attack FA along foraging trails, so a technique was used to survey, which involved placing baits to recruit FA workers and then using sticky traps to capture flies near the bait. The sticky cards recovered a different parasite fly, demonstrating potential for the technique, but did not recover the new parasite at this time. New techniques and results from applied research were provided to nursery growers, landscapers, regulatory, and other public stakeholders at multiple educational venues. Producer and stakeholder attendance at workshop presentations by our program or by others using information from our program were estimated at 838 during this fiscal period. In addition, we received 36 direct requests for information on invasive insects and their management from growers or extension agents during the period, which we estimate impacted 2,122 producers and 241 stakeholders. Another objective of this project is to identify diseases that impact nursery production system and develop disease management strategies. Research on control agents focused on methods of application with two biological control bacteria and two fungi. Drenching of seedlings with two bacteria and two fungi was as effective as foliar spray against powdery mildew in dogwood seedlings and the occurrence of two bacteria and a fungus was confirmed in the plant tissue. Also, two bacteria were found to be effective in controlling root rot and boosting plant growth. Research on diseases of economic concern to growers focused on cherry leaf spot of flowering cherry in which results on effective fungicides and the timing of disease establishment were confirmed. Four fungicides; two newer formulations and two older copper-based fungicides were evaluated individually and in rotations; they were all highly effective in controlling cherry leaf spots, shot hole and defoliation. Previously infected plants developed infection in greenhouse environment where they were protected from airborne sources of infection. Results confirmed that cherry leaf spot may overwinter in the dormant buds and be the source of infection in spring. Impact of research findings have enabled growers to control cherry leaf spot by proper timing of fungicide applications and by avoiding plant propagation from previously infected plants. The effective control of cherry leaf spot in flowering cherry was evident in the increased plant growth and market value. Two growers we worked with had first hand benefit of results and continue to play an important role in dissemination of research results to other growers in southeastern states where these plants are marketed.

4. Accomplishments

Last Modified: 07/25/2017
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