Managing pesticides for crop production and water quality protection: practical grower guides

Abstract

A decision aid has been developed for use by farmers and other pesticides users that permits the selection of pesticides on the basis of water quality impact in addition to efficacy and cost as is tradionally done. This ‘kitchen table’ decision aid uses information on environmental fate and toxicity of pesticides, soil leaching potential or run-off ratings in combination with pest management guidelines to make site-specific selections that minimize the potential impacts of pesticide use on water quality. Pesticide properties used include the sorption coefficint ( K oc), degradation half-life, lifetime health advisory level (HAL), and aquatic toxicity. The first two properties are used to derive a relative leaching potential index, RLPI, and a relative run-off potential index, RRPI, for each pesticide. Site-specific soil ratings for pesticides leaching and run-off, provided by the US Department of Agriculture Soil Conservation Service, are matched with these indices and toxicity values via a table of selection criteria. A pesticide selection worksheet is provided to organize the necessary information to make an informed decision. This decision aid assists the pesticide user in understanding the water quality impacts of alternative pesticide selection. Thse grower guides are customized to individual crops. They include a table of pesticides registered for use on the crop, organized by major use category (herbicides, insecticides, nematicides, fungicides, and soil fumigants). Within categories, trade names, common names, application type (soil vs. foliar), K oc, RLPI, RRPI, HAL, and aquatic toxicity are listed. These grower guides can easily be adapted for use in other states or countries. This technology will not only help agricultural and urban pesticide users select pesticides with less water quality impact, but will also aid regulatory agencies in developing meaningful groundwater protection plans, and hopefully will result in more equitable public policy decisions.