Methyl isothiocyanate and chloropicrin concentrations in bareroot forest nursery soils and above soil surface treatments following fumigation
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In: Dumroese, R. K.; Riley, L. E., tech. coords. National Proceedings: Forest and Conservation Nursery Associations-2007. Proc. RMRS-P-57. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 38-45
Concentrations of methyl isothiocyanate (MITC) and chloropicrin (CP) in air spaces of nursery soil and in air at the soil surface following fumigation were determined in field trials in a Wisconsin and a Georgia nursery. MITC was measured in plots receiving either dazomet or co-application of metam sodium and chloropicrin; CP was measured in the latter plots. Soil surfaces were sealed with either a high density polyethylene tarp or by surface compaction and maintenance of a water seal following fumigation. Findings from the Wisconsin trial are highlighted. A very small percentage (< 3%) of the applied MITC was lost to the atmosphere, either through the plastic or water-sealed surfaces during the 14 days following treatment. For CP, 10% and 22% of the applied equivalent were calculated to have been lost to the atmosphere in the plastic-covered and water-sealed plots, respectively. Low MITC air emissions and MITC presence deep in the soil profile in the dazomet, water-sealed plots are partly attributed to over-irrigation on 5 of the 7 days following fumigation in Wisconsin. However, slightly higher, but still low, emissions in similar plots without excess watering in the Georgia nursery show that either surface containment method can be used in nurseries to reduce risk of MITC emissions to nearby seedling crops or harm to humans in nearby fields. The use of plastic tarps increases death rates of Fusarium propagules by maintaining higher chemical levels in the soil profile over time; however, dazomet has been used with water-seal treatment to give consistent, satisfactory control of soilborne pests in nurseries in the northern US.
Keywordsdazomet, metam sodium, methyl bromide alternatives, soilborne pests, disease control
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Juzwik, Jennifer. 2008. Methyl isothiocyanate and chloropicrin concentrations in bareroot forest nursery soils and above soil surface treatments following fumigation. In: Dumroese, R. K.; Riley, L. E., tech. coords. National Proceedings: Forest and Conservation Nursery Associations-2007. Proc. RMRS-P-57. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 38-45