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Generation and Dissipation of Methyl Isothiocyanate in Soils Following Metam Sodium Fumigation: Impact on Verticillium Control and Potato Yield

May 2007 , Volume 91 , Number  5
Pages  497 - 503

Shachaf Triky-Dotan , Miriam Austerweil , and Bracha Steiner , Laboratory for Pest Management Research, Institute of Agricultural Engineering, ARO, the Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel ; Yitzhak Peretz-Alon , Agricultural Committee, Maon Region Enterprises Israel ; Jaacov Katan , Department of Plant Pathology and Microbiology, the Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Rehovot 76100, Israel ; and Abraham Gamliel , Laboratory for Pest Management Research, Institute of Agricultural Engineering, ARO, the Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel



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Accepted for publication 16 October 2006.
ABSTRACT

The fate of methyl isothiocyanate (MITC) was studied in agricultural soils following metam sodium (MS) application in a controlled system and under field conditions as it was related to disease control. Soil samples were collected from 34 field sites in Israel with no history of MS application. The generation and dissipation curves of MITC in these soils, under controlled conditions, varied significantly among the soils, as reflected by the concentration by time (C × T) product. This value was significantly related with the mortality level of Fusarium oxysporum f. sp. radicis-lycopersici as a test organism and sand content of the soils. Seven field experiments were conducted in potato fields from 2001 to 2004. The MS treatments significantly reduced Verticillium wilt incidence and severity in five and four experiments, respectively, out of seven. Combining MS with formalin was more effective for controlling disease than MS alone in most cases. A significant relationship was found between mortality of F. oxysporum f. sp. radicis-lycopersici in soil samples to which MS was applied under controlled conditions and the incidence of Verticillium wilt disease in the field, and between CMITC × T products and the incidence of Verticillium wilt disease in the field. These tests can be used for preplant assessment of potential MS efficacy.


Additional keywords: gas liquid chromatography, soil disinfestation, solid-phase microextraction, Verticillium dahliae

© 2007 The American Phytopathological Society