Chloropicrin RED

NATIONAL POTATO COUNCIL 1300 L Street, NW, Suite 910 Washington, DC 20005 202.682.9456 ? 202.682.0333 fax www.nationalpotatocouncil.org spudinfo@nationalpotatocouncil.org February 28, 2007 (Via Email mottl.nathan@epa.gov or Via Fax 703-305-0208) Office of Pesticide Programs (OPP) Regulatory Public Docket (7502 P) Environmental Protection Agency 1200 Pennsylvania Ave. N.W. Washington, DC 20460-0001 Re:Preliminary Risk Assessment of Chloropicrin EPA-HQ-OPP-2006-0661 Chloropicrin is used on potatoes in the Pacific Northwest (WA, ID and OR), the Upper Midwest and Florida for nematodes and a mix of soil diseases. Wireworms are also a target pest in the PNW. Scab is a target pest in the Upper Midwest and Florida. Chloropicrin products used on potatoes include C-17, C-35, C-60, which contains chloropicrin and 1,3-dichloropropene and Pic Plus which contains chloropicrin and paraffin. Growers in the PNW use C-17. Growers in the Midwest use Pic Plus. Growers in Florida use C-17, C-35 and C-60. The primary reason it is used is that it is the only means to control wireworms, nematodes and soil diseases in a single application. Otherwise, growers must first apply Telone 2, then wait a period of time, most often 2 weeks, then apply metam sodium, then wait about 3 weeks before planting. In many cases, weather conditions (soil temperatures) do not allow sufficient time to make both applications. Chloropicrin has been shown to control black dot, scab and silver scurf, something that no other soil applied fungicide has been shown to do. Although research data are minimal, grower experiences indicated that yield and quality are higher following use of chloropicrin based products. As a result, usage of chloropicrin on potatoes is increasing, particularly in the Midwest and Florida. In certain situations, particularly in soils that have received frequent applications of metam sodium, products containing chloropicrin provides superior control of soil disease. Another advantage of using products than include chloropicrin is that it can be applied in the absence of surface irrigation water. Most potatoes in the PNW are irrigated with surface water which is available only in certain times of the year. The most common and effective means of applying metam sodium is via chemigation, which means irrigation water is necessary. In certain situations growers need to apply a soil disease product when no surface water irrigation is present. In this situation, C-17 is required in lieu of metam sodium. Buffer zones of 100 feet next to occupied structures are required when applying C- 17 to soils that are to receive 1, 3-dichloropropene during the next 3 years. Because potatoes in the PNW are usually rotated at least every 3 years, very little ground is fumigated with 1, 3-dichloropropene in less than 3 years. Therefore, it is rare for C-17 applications to require buffer zones in the PNW. Buffer zones for Pic Plus are already in place in the Upper Midwest and these buffers provide adequate protection. There have never been a human health or environmental incident associated with the use of chloropicrin on potatoes. Chloropicrin is always applied as a preplant soil fumigant. All applications require closed systems with dry disconnects. All application equipment have end row spillage controls. All applicators are specially certified. All applicators and handlers undergo annual training carried out in conjunction with the state departments of agriculture. All chloropicrin is applied 16 to 18 inches below the soil surface. The soil is sealed using a disk or similar device followed by a cultipacker. All chloropicrin is custom applied. If large buffer zones are required for the use of chloropicrin, it could threaten the continued use of this product on potatoes. Buffer zones should not be the primary focus of the risk assessment as current agricultural practices control emissions. Application practices such…