Alternatives to Methyl Bromide Soil Fumigation for Florida Vegetable Production

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Florida growers, who have continued to rely on existing and internationally approved CUE supplies of methyl bromide, painfully recognize an increase in price, a future of diminishing supply, and the limits to which methyl bromide use rates can be reduced without loss of pesticidal efficacy and crop yield. Local competitive pressures have led to Florida growers being reluctant to transition to new integrated pest management strategies which include co-application of different fumigants and herbicides, and adoption of other alternative cultural practices to achieve pest control efficacy and crop yield response similar to that of methyl bromide.
Transition to the alternatives has also required growers to implement other significant changes to current practices, including integration of new fumigant distribution and soil injection technologies, and new tillage and irrigation prac - tices to enhance the performance of alternatives and reduce potential fumigant emissions from treated fields. With Phase 2 labels and completion of the formal EPA fumigant reregistration process (spring 2012), all of the currently registered fumigant alternatives will have new restrictions which will further restrict or limit their use (i.e., potential needs for reduced rates and acreages treated per day and expanded buffer zones. The new regulatory criteria for fumigant use are designed to strongly encourage emis - sion reduction strategies which include high barrier (more gas impermeable) plastic mulches to reduce overall field application rates and soil emissions of fumigant gases. Grower transition to these new IPM methods (dashed blue line Figure 1) have been largely and only recently driven by limited methyl bromide supply and formulation avail - ability, a significantly lower cost structure for combina - tions of chemical alternative strategies compared to that of methyl bromide, and by many other field, pest, soil, crop, and economic considerations. The primary objective for any methyl bromide transition strategy has been to manage adoption of alternatives over time, to minimize changes to the crop production system, and define and remove perfor - mance inconsistency of alternatives.

J. W. Noling
D. A. Botts
A. W. MacRae
University of Florida, IFAS Extension