Progress 10/01/12 to 09/30/13
Outputs
Target Audience: The target audiences for this work include county extension agents and squash growers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? A post-doctoral associate assisted with parts of the evaluation and learned more about field trials in cucurbits. How have the results been disseminated to communities of interest? The results were presented at a tri-state cucurbit growers meeting (Florida, Georgia, Alabama) organized by a county extension agent in Washington County, Florida. What do you plan to do during the next reporting period to accomplish the goals? This is the final progress report for this project.
Impacts
What was accomplished under these goals?
We evaluated several products compatible with IPM practices in squash to better advise growers about the value of mixing products with different modes of action. There was no benefit to adding a pyrethroid to a neonicotinoid insecticide to control whiteflies. This practice is also detrimental to pollinators. We also confirmed that it is impossible to manage very high populations resulting from an influx of insects leaving nearby harvested field crops, such as peanuts. Cucurbit leaf crumple virus (whitefly transmitted) infected almost 100% of plants with two weeks of emergence, confirming the serious problem this virus is causing even in north Florida.
Publications
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: During this reporting period, insecticide trials were conducted in the fall of 2011 to evaluate materials for control of sweetpotato whitefly, Bemisia tabaci. In the spring, we conducted a cooperative project with a faculty member in Horticulture to evaluate effects of different organic fertilizer rates on the abundance of aphids and whiteflies on squash. Two different approaches to organically managing insects on squash were included at all fertilizer rates. Results from the fall trial were shared at two grower meetings and the spring experiment served as a demonstration for two workshops, one to train county extension agents in vegetable pest management and the other to train small farmers. In addition to viewing the organic squash trial, participants learned scouting methods for insects in six different vegetable crops through a hands-on experience that included collecting and identifying insects from vegetables. Several undergraduate students also learned scouting techniques by participating on a weekly basis in the spring. PARTICIPANTS: Susan Webb was the PI on this project. Several undergraduate students, Alyssa Porter, Sarah Larson, and Chelsea Wilkinson, assisted with field projects. We partnered with the Suwannee Valley Agricultural Extension Center and collaborated with Dr. Danielle Treadwell, Horticultural Sciences Dept., University of Florida on the organic squash experiment. TARGET AUDIENCES: The target audience for workshops that incorporated the field projects as demonstrations included county extension agents and small farmers. University of Florida undergraduate entomology majors were also an audience as well as participants in the projects. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Evaluation of an inservice training for county agents in vegetable pest management showed a modest gain in knowledge, but revealed strong motivation to share the training with constituents.
Publications
- Webb, S. April 2012. Squash bugs. Vegetarian Newsletter No. 573, Horticultural Sciences Dept., University of Florida, http://hos.ufl.edu/newsletters/vegetarian/issue-no-573
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: During this reporting period, insecticide field trials were conducted to evaluate new pesticides aimed at controlling whiteflies and the viruses they transmit. Materials were applied as foliar treatments to both squash and cucumber and also through drip irrigation. In greenhouse tests, insecticides known to interfere quickly with feeding by adult whiteflies were applied to virus source plants and healthy target plants in all possible combinations to determine if virus transmission would be affected. Ten students were trained to identify and count whiteflies, both on plants in the field and with the use of microscopes in the laboratory. In further experiments with Squash vein yellowing virus, the time between inoculation (both mechanically and by whiteflies) and subsequent acquisition was determined. A graduate student was trained in scouting techniques for vegetables in an IPM demonstration trial. PARTICIPANTS: Susan Webb (PI) planned and analyzed most of the research conducted. A Doctor of Plant Medicine student, Bonnie Wells, completed an internship in vegetable IPM. TARGET AUDIENCES: Florida vegetable growers, particularly those growing cucurbits, were the target audience for presentations based on the research conducted. This group includes racial and ethnic minorities. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Information gained from field and greenhouse trials will contribute to the registration of new, selective insecticides and to recommendations for Florida vegetable growers. So far, the materials we have evaluated in greenhouse trials are most effective in reducing secondary spread of disease. If whiteflies have been able to acquire virus from untreated plants, they can transmit to treated plants, although at a reduced rate, and although they do not survive on these plants. Students working on several projects learned new skills.
Publications
- No publications reported this period
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Activities during this period included a whitefly sampling study in watermelon to determine the within-plant distribution of both adults and immature stages. Pest management work included experiments to evaluate the residual effects of soil-applied insecticides on Colorado potato beetle in potato, and to evaluate effects of experimental materials on whiteflies in cucurbit crops. Greenhouse experiments were done to evaluate the effects of one of these materials on transmission of Squash vein yellowing virus by the whitefly, Bemisia tabaci. Other greenhouse experiments evaluated effects of mixed viral infections on transmission of this virus. Information was disseminated through a multi-county and a multi-state grower meeting and through presentations at conferences (Entomological Society of America and American Phytopathological Society). PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Vegetable growers, both commercial and homeowners, are the target audience for this work. Students learning about insect management in vegetables and those learning about insect-vectored viruses are also included. Extension activities included several grower meetings. Eight undergraduate student participated in an 8-week pest management experience, another student spent 8 weeks in my laboratory studying whitefly behavior in regard to preferences for and survival on virus-infected plants, and lectures to Doctor of Plant Medicine students increased their knowledge of vegetable pest management. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Findings were shared with vegetable growers, who reported increases in knowledge measured in pre and post tests.
Publications
- No publications reported this period
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Experiments were conducted to evaluate retention of Squash vein yellowing virus by the whitefly, Bemisia tabaci, B strain. Minimum transmission time (acquisition plus inoculation) was also determined. A greenhouse experiment evaluated the effects of pymetrozine on transmission of the virus from and to squash, testing all possible treatment combinations. A field study was conducted in Live Oak, FL to determine the distribution of immature whitefy stages on watermelon vines (both seeded and seedless varieties), including secondary runners. Results were presented at several grower meetings and two national scientific meetings. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Results of the sampling study are still being analyzed. The results of transmission experiments will ultimately impact management of Squash vein yellowing virus, but the work has only just been completed and has not yet been published. Results of the pymetrozine study should impact the recommendations of professional scouts for managing whiteflies and the viruses they vector in watermelon (i.e., saving this material until virus is actually found in the crop).
Publications
- No publications reported this period
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Several trials were conducted to evaluate new insecticides. Synapse (flubendiamide) was evaluated for pickleworm and melonworm control on squash in the fall of 2007 and Movento (spirotetramat) and Admire (imidacloprid) were evaluated separately and together for whitefly and aphid control in potatoes and watermelon in the spring of 2008. The new materials were highly effective, although a rotation of spinosad and Bacillus thuringiensis was more effective than Synapse for pickleworm control. These materials have now been approved for use in several vegetable crops in Florida. Movento should be available for use in cucurbit crops in the near future. During this project period, in a greenhouse trial, I tested the effects of two concentrations of a botanical insecticide, derived from Chenopodium ambrosioides, on the ability of aphids to vector a nonpersistently transmitted potyvirus that affects cucurbits. In the first experiment, the target plants were treated to look at effects on inoculation of virus acquired from infected, untreated plants. In the second experiment, the virus source plants were treated to look at effects on acquisition. The botanical insecticide, at a 1.0% concentration, reduced aphid survival, but had no effect on virus transmission if the target plants were treated. There was a reduction in transmission when source plants were treated (from11/15 of untreated plants to 5/15 of the treated plants. The next step will be to treat both source and target plants, which would mimic a situation where spread of virus is from plant to plant within a field. Multiple experiments were done to characterize transmission of Squash vein yellowing virus by whiteflies, including tests of efficiency, minimum inoculation and acquisition access periods, and retention time by the vector. Results of trials and experiments were disseminated by presentation at grower meetings and at a national meeting (American Phytopathological Society). PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: County extension faculty and vegetable growers were the target of most of the efforts in this project. Talks were presented at several meetings organized by county extension faculty. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of pesticide trials have helped with expansion of labels to new crops and have provided useful information for extension agents making recommendations to growers. Results of transmission studies with SqVYV have supported whitefly management and the use of reflective mulches as approaches to control of watermelon vine decline.
Publications
- Akad, F., Webb, S. E., Nyoike, T. W., Liburd, O. E., Turechek, W. W., Adkins, S. & Polston, J. E. 2008. Detection of Cucurbit leaf crumple virus in Florida cucurbits. Plant Disease 92: 648.
- Adkins, S., Webb, S. E., Baker, C. A. & Kousik, C. S. 2008. Squash vein yellowing virus detection using nested polymerase chain reaction demonstrates that the cucurbit weed Momordica charantia is a reservoir host. Plant Dis. 92:1119-1123.
- Li, W., Hilf, M. E., Webb, S. E., Baker, C. A., and Adkins, S. 2008. Presence of P1b and absence of HC-Pro in Squash vein yellowing virus suggests a general feature of the genus Ipomovirus in the family Potyviridae. Virus Res. 135:213-219.
- Nyoike, T. W., Liburd, O. E. and Webb, S. E. 2008. Suppression of whiteflies, Bemisia tabaci (Hemiptera: Aleyrodidae) and incidence of Cucurbit leaf crumple virus, a whitefly-transmitted virus of zucchini squash new to Florida, with mulches and imidacloprid. Florida Entomol. 91:460-465
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