Chapter 7
Turfgrass Dissipation of Cyazofamid Downloaded by PURDUE UNIV on June 27, 2016 | http://pubs.acs.org Publication Date (Web): December 20, 2009 | doi: 10.1021/bk-2009-1028.ch007
Jerome L. Wiedmann ISK Biosciences Corporation, 7470 Auburn Rd., Suite A, Concord, OH 44077
Traditionally, the fate of pesticides applied to turf has been measured by a 120-day dissipation study to satisfy the United States Environmental Protection Agency (USEPA) data requirements. The focus of these studies has been to measure the rate of degradation of the active ingredient and its degradates as well as to assess the potential for leaching of each of these compounds into the soil. Historically, all grass clippings were left on the plot to recycle the residues. Recently, concern has also been raised about the loss of residues from the treated area via removal of the grass clippings during the mowing process. The fate of cyazofamid, a cyanoimidazole fungicide, used for Pythium control in turf was investigated with and without removal of clippings at sites in North Carolina and Virginia. Comparison of loss of cyazofamid by clipping removal to other mechanisms of dissipation indicates that for a pesticide such as cyazofamid, which has very short foliar and soil half-lives and which does not leach, the loss due to removal in the clippings is minimal (0.7-2.2%). Even with application rates of 1 lb a.i./A, dissipation of cyazofamid from turf was rapid (half-lives of 18 to 19 days). There was very little movement of either cyazofamid or its degradates into the soil. By 120 days after the last of three applications, 94-98.8% of the applied cyazofamid had degraded (primarily in the form of bound residues).
© 2009 American Chemical Society Nett et al.; Turf Grass: Pesticide Exposure Assessment and Predictive Modeling Tools ACS Symposium Series; American Chemical Society: Washington, DC, 2010.
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Downloaded by PURDUE UNIV on June 27, 2016 | http://pubs.acs.org Publication Date (Web): December 20, 2009 | doi: 10.1021/bk-2009-1028.ch007
Background Cyazofamid [4-chloro-2-cyano-N,N-dimethyl-5-p-tolylimidazole-1sulfonamide (IUPAC), 4-chloro-2-cyano-N,N-dimethyl-5-(4-methylphenyl)-1Himidazole-1-sulfonamide (CA)] is a fungicide developed by Ishihara Sangyo Kaisha, Ltd. It has excellent activity on all life stages of Oomycete fungi such as Phytophthora, Plasmopara, Pythium, Pseudoperonospora and Aphanomyces. Effective preventative activity is observed at 60-80 g/ha (0.052-0.071 lb a.i./A). Cyazofamid is currently registered in the United States for use on potatoes, tomatoes, cucurbits and imported wine grapes. Additional uses are under investigation. Pythium control on turf grass is a pending registration. Important properties of cyazofamid include low water solubility (0.107 mg/L) and a low vapor pressure (
