Field Evaluation of Potential Methyl Bromide Replacements for Grape Growers
Methyl bromide has provided an almost fool-proof procedure for avoidance of the replant problem including long-term relief from soil pests. Our suggested alternatives to methyl bromide can provide equivalent protection in some settings but not others. In vineyards the shortcomings will occur in finer-textured soils, settings having oak root fungus, settings having grape fan leaf virus and Xiphinema index, settings having aggressive root knot populations where previous rootstocks have failed, settings where root lesion is a problem including varietals such as Zinfandel. There is also no assurance that Telone or Vapam will be available as needed. Rootstocks provide some of the answer when properly started out and when broad soil pest protection is available. Some growers will lose the ability to quickly pull and replant their vineyards so fallow periods will be lengthened. Post-plant nematicides will become more popular. We have identified combination soil treatments with potential to replace methyl bromide but we need these studies to verify their performance and identify their limitations. Meanwhile, some of these soil pests including Xiphinema index and aggressive root knot nematode populations are now more prevalent in vineyard settings. Unfortunately, fumigants kill old grape roots and we have found no other treatment that does.