Improvements and Replacements for Pre-Plant Soil Fumigation
Garlon at 5 and 10 grams active ingredient applied to foliage or applied as a paint to stumps was highly effective at killing the surface 1 foot of grape roots and all aboveground portions. It was ineffective, however, at killing roots below 1 foot soil depth. Certain grape rootstocks are more sensitive to the replant problem than others. Teleki 5C is among the more sensitive, whereas own-rooted V. vinifera appears less sensitive. We now have good evidence that Vapam at 100 gpa is a mediocre performer relative to killing old roots and that treatments with Vapam, like methyl bromide or Telone, result in a biological vacuum. By broadcast drenching at 200 gpa and then growing nonhosts for the nematodes in the next year we have in one large trial achieved nematode control and vine growth comparable to that achieved with methyl bromide. We now need to adjust the treatment rates lower to find the best rates for use in vineyards as compared to orchards. Telone or Acrolein applied via a drencher at rates equivalent to 100 gal/acre Vapam will outperform Vapam. Applied via drencher Telone volatilization can be reduced from that which occurs after conventional shank injections.