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United States Department of Agriculture

Agricultural Research Service


Location: Crops Pathology and Genetics Research

2009 Annual Report

1a.Objectives (from AD-416)
1. Demonstrate alternatives to MB in key crop systems and regions dependent upon MB. This will be accomplished by conducting replicated, large-scale field trials that will compare standard treatments with MB to the best available alternatives. The alternatives will include substitute fumigants and supporting integrated pest management (IPM) practices. The trials will be conducted by multi-disciplinary teams in partnership with commercial growers at field locations that collectively represent the diversity of the commercial production systems.

2. Conduct comprehensive assessments of alternatives to MB in key crop systems and regions dependent upon MB. This will be accomplished by multi-disciplinary collection and analysis of biological, environmental, and economic data from the trials described above.

3. Identify key variables affecting the efficacy of MB alternatives and demonstrate management and predictive use of the variables to optimize performance of the alternatives.

4. Assess and demonstrate emissions reduction technologies and strategies for fumigant alternatives to MB.

5. Conduct multi-regional education programs that instruct growers, farm workers, and associated members of the agricultural community on optimized, IPM-supported use of MB alternatives.

1b.Approach (from AD-416)
The project will achieve its objectives by using a collaborative, inter-disciplinary approach and will include operational, assessment, and educational components. The operational component will involve horticulturists, soil and atmospheric chemists, plant pathologists, nematologists, weed specialists, engineers, economists, extension educators, and regulatory specialists working together with commercial growers, nurserymen, advisors, and other agricultural workers. The teams will demonstrate, assess, and optimize use of MB alternatives in commercial fields. The optimizations will focus on identifying and managing variables that maximize fumigant efficacy and minimize fumigant emissions. Where appropriate, integrated pest management practices will be demonstrated and evaluated for contributions to optimizing MB alternatives. The assessment component of the project will involve advanced analysis of economic, environmental, and social data obtained from the field trials. As information accumulates from activities in the operational and assessment components, it will be extended to end users in the educational component of the project. Educational outreach will be achieved via indoor and outdoor extension meetings, newsletters, educational websites, and peer-reviewed and popular publications. Teams involved in the operational, assessment, and educational components will be drawn from diverse public and private institutions, including, but not limited to: USDA-ARS (Davis, Parlier, Riverside, and Salinas locations, with possible contributions from Corvallis and Wenatchee); University of California, including UC Cooperative Extension; California Environmental Protection Agency; California Department of Food and Agriculture; commercial fumigant applicators and manufacturers; marketing and research boards for horticultural commodities; and producers.

3.Progress Report
A team of scientists, project leaders, and industry and regulatory stakeholders was convened and reviewed, revised, and approved 12 continuing research and demonstration projects. The projects are based in CA, OR, and WA and designed to facilitate effective transitions to integrated, economical methyl bromide (MB) alternatives for industries served by critical use exemptions for pre-plant soil fumigation with MB. Crop systems included are strawberry; almond and other stone fruits (peaches, plums, etc.); grape; walnut; sweet potato; cut flowers; perennial fruit, nut, and ornamental nurseries; raspberry nurseries; and forest nurseries (i.e., Western US crops impacted most severely by the MB phaseout). The 12 projects are testing and demonstrating: a) fumigant alternatives to MB, b) new fumigant application and emissions reduction technologies that improve fumigant efficacy and reduce non-target fumigant emissions, and c) integration and replacement of fumigant alternatives to MB with non-fumigant alternatives. The activities fall mainly under NP308 Problem Statements 1A and 1B yet also facilitate 1C. Each has project conducted field trials and educational outreach designed to foster stable transitions to MB alternatives for the crops served. Multiple strawberry trials were evaluated and demonstrated:.
1)reduced rates of fumigant alternatives to MB;.
2)improved impermeable mulches (virtually impermeable and totally impermeable films, VIF and TIF, respectively); and.
3)non-fumigant alternatives to MB. (i.e., non-fumigant pesticides, steam treatments, cultivar resistance). Ten almond and peach replant trials were monitored or established to examine and demonstrate:.
1)efficacy of fumigant alternatives to MB in different replant scenarios,.
2)use of GPS-controlled and drip spot application technologies that facilitate reductions in fumigant use and emissions, and.
3)integrations with optimized cultural practices (fallowing, crop rotation, careful soil water management) to reduce dependence on or improve efficacy of alternative fumigants. The grape, walnut, sweet potato, cut flower, perennial nursery, and raspberry nursery projects each established and continued field trials testing and demonstrating alternative fumigants and plastic mulch systems. Mustard cover crop rotation was tested as an alternative to fumigation for grape, and solarization was tested as an alternative and supplement to fumigation in raspberry and sweet potato nurseries. Three of the projects examined atmospheric emissions reductions achieved using improved plastic mulches (VIF and TIF), soil surface treatments, and spot application methods. All projects conducted educational outreach at field demonstrations, extension meetings, and scientific conferences.

1. Methyl bromide (MB) alternatives for cut flower and bulb production. Cut flower and bulb production operations in California need effective replacements for preplant soil fumigation with MB, which is typically applied by shanks in field operations and the “hot gas” method in enclosed operations (i.e., greenhouses, hoop houses). Multiple research and demonstration trials conducted by ARS scientists in Davis, CA were completed statewide in commercial plantings of Ranunculs and calla lily (field operations), iris, freesia and snapdragon (enclosed operations) to test drip applications of chloropicrin and combinations of it with 1,3-dichloropropene and metam sodium as alternatives to shank and hot gas applications of MB. The trials established and demonstrated to growers that the drip-applied alternatives provide pest control and crop yields equal to or better than those obtained with the conventional MB treatments. The work is resulting in commercial transition to the drip alternatives for cut flower and bulb production and therefore is:.
1)reducing reliance on MB and.
2)reducing fumigant emissions to the atmosphere, which are significantly greater following shank and hot gas fumigation than following drip fumigation.

2. Integration of alternative fumigants with improved plastic mulches for replacement of methyl bromide (MB) for strawberry production-Strawberry fruit production operations in California need effective replacements for MB that are compatible with tightening regulatory restrictions. ARS scientists at Davis, CA in collaboration with commercial strawberry growers, completed multiple research and demonstration trials across California’s coastal strawberry production districts to test reduced rates of drip-applied fumigant alternatives to MB in combination with low permeability plastic mulches (i.e., semi-impermeable film or SIF, virtually impermeable film or VIF and totally impermeable film or TIF). The trials established and demonstrated to growers that low rates of fumigant alternatives (i.e., combinations of chloropicrin with 1,3-dichloropropene), if applied under a low-permeability plastic mulch, can be used to obtain strawberry yields equivalent to those following conventional treatments with MB-chloropicrin combinations. Furthermore, data were obtained to confirm that the low permeability mulches retain fumigants in soil longer than conventional high density polyethylene mulches, thereby improving fumigant efficacy and reducing atmospheric emissions. This research also has demonstrated the feasibility of gluing impermeable films for broadcast fumigation. The work has provided strawberry growers with valuable alternatives to MB that are effective and conducive to use under current regulatory restrictions.

Last Modified: 9/21/2014
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