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United States Department of Agriculture

Agricultural Research Service

Research Project: Alternatives to methyl bromide soil fumigation for vegetable and floriculture production
2012 Annual Report


1a.Objectives (from AD-416):
Identify impact of pest management tactics on functional diversity of soil microflora and weed populations, their competitive interactions, and effects on crop health. Conceive, develop, and test tactics for the control of plant diseases, parasitic nematodes and weed pests of vegetable and floriculture crops. Research efforts will concentrate on the testing of novel chemical, biological, biorational, cultural, and organic pest conrol tactics and on improving their application technology. Identify combinations of pest control tactics that interact synergistically to improve pest control, are practical to implement, and will minimize environmental disruption. Research activities will focus on identifying combinations of pest control tactics that produce synergistic effects and minimize disruption to conventional crop production practices. Define the impacts of pest management and crop production practices on soil health including the suppression of soilborne pests.


1b.Approach (from AD-416):
A rational and sustainable approach to finding viable alternatives to methyl bromide is to utilize integrated pest management (IPM) programs where combinations of tactics are used to maintain economic damage from key pests below a tolerable threshold. Another approach is to redesign production systems minimizing the potential for outbreaks of soilborne pests. Availability of biologically-based pest management tactics must be increased for successful IPM programs for soilborne pests to be implemented. Growers must have the option of choosing tactics that fit the needs and constraints of their individual programs. Deployment of multiple or companion tactics is essential to alleviate selection pressure and manage potential increases in resistant pest populations. Synergistic effects from combinations of pest management tactics need to be determined. Specific research methodology will include combinations of cultural practices, biotechnology, biological, and conventional control methods.


3.Progress Report:
Research was conducted in cooperation with University of Florida to continue evaluation of a new reduced-risk compound for control of weeds, plant pathogenic fungi and bacteria, and plant parasitic nematodes. Research continued on anaerobic soil disinfestations (ASD) where previous results showed control of yellow nutsedge emerging though the plastic early in the season with ASD was equivalent to methyl bromide in one field trial. Root-knot nematode control was influenced by initial irrigation, molasses addition, and by the incorporation of composted broiler litter. Further field trials have been conducted on ASD in cooperation with private crop consultants and trials are currently underway in cooperation with a commercial caladium grower. In a Florida field trial examining alternatives to fumigants for production of field-grown cut flowers, weeds were collected, identified, and evaluated for galling by root-knot nematodes (Meloidogyne spp.). Cheeseweed mallow (Malva parviflora L.) was determined to be infected with Meloidogyne arenaria, and greenhouse experiments confirmed and quantified the host status under controlled conditions. This was the first report of M. parviflora as a natural host of M. arenaria. Further nematode host range studies were conducted to assess galling and egg production of three common root-knot nematode species, M. incognita, M. arenaria, and M. javanica on weeds common in Florida production, Portulaca oleracea (purslane), Eleusine indica (goosegrass), Aeschynomene americana (American jointvetch), Solanum americanum (American black nightshade), Cyperus esculentus (yellow nutsedge), and Amaranthus retroflexus (redroot pigweed) were evaluated. Funding was acquired through IR-4 to evaluate new formulations and applications methods for the commercial nematode biological control agent Pasteuria penetrans.


4.Accomplishments
1. Reduced risk chemicals for weed, nematode, and pathogen control. Crop protection materials are needed that provide broad-spectrum control of pests, but do not pose a risk to workers or the environment. Research was conducted in cooperation with University of Florida to continue evaluation of a novel, reduced-risk compound for control of weeds, plant pathogenic fungi and bacteria, and plant parasitic nematodes. The compound’s broad-spectrum pest control activity at relatively low application rates and methods was further defined in field trials. Significant findings of this research include the effects of the reduced-risk chemical on populations of beneficial fungi. In addition, the experimental compound does not produce any volatile organic compounds, thereby limiting potential by-stander risks as well as increasing its potential for use between crops.

2. Anaerobic soil disinfestation as an alternative to methyl bromide fumigation. A cooperative research project between ARS in Fort Pierce, FL, and the University of California, Santa Cruz has generated new information on Anaerobic Soil Disinfestation (ASD), a technique that utilizes the combination of a nitrogen source, such as composted broiler litter, and a carbon source, such as molasses, with soil saturation and heating to create an anaerobic condition that induces weed, nematode, and soilborne plant pathogen control. Control of yellow nutsedge emerging though the plastic early in the season with ASD was equivalent to methyl bromide in one field trial. Root-knot nematode control was influenced by initial irrigation, molasses addition, and by the incorporation of composted broiler litter. ASD was found to be more effective in the control of the strawberry charcoal rot pathogen than were the commercial standard or other experimental control measures.

3. Susceptibility of weeds common in Florida to Meloidogyne spp. In a Florida field trial examining alternatives to fumigants for production of field-grown cut flowers, weeds were collected, identified, and evaluated for galling by root-knot nematodes (Meloidogyne spp.). Cheeseweed mallow (Malva parviflora L.) was determined to be infected with Meloidogyne arenaria, and greenhouse experiments confirmed and quantified the host status under controlled conditions. This was the first report of M. parviflora as a natural host of M. arenaria. In greenhouse trials to assess galling and egg production of three common root-knot nematode species, M. incognita, M. arenaria, and M. javanica on weeds common in Florida production, Portulaca oleracea (purslane), Eleusine indica (goosegrass), Aeschynomene americana (American jointvetch), Solanum americanum (American black nightshade), Cyperus esculentus (yellow nutsedge), and Amaranthus retroflexus (redroot pigweed) were evaluated. Although recommended as a cover crop in the southern U.S., A. americana was evaluated as a weed following a heavy volunteer infestation of an experimental field in southeastern Florida where galling was observed on roots.


Last Modified: 11/27/2014
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