The foundation of a strong powdery mildew program is early season sprays with wettable sulfur
or Stylet oil when vines have 3 to 6 inches of growth.
Things like highly scented deodorant soap, rotten eggs, ammonia, wettable sulfur
, garlic, clumps of human hair and even cheap perfume or aftershave tend to turn deer away.
During the growing season, spray foliage with a wettable sulfur
, or a fungicide such as triforine.
changed from a mineral oil program to wettable sulfur
for powdery mildew control in their organic 60-acre vineyard.
Otherwise, apply low-toxicity wettable sulfur
to the foliage (be sure to cover the bottoms of the leaves) to keep this disease in check.
Organic growers realized that relying simply on sulfur dusting or wettable sulfur
for powdery mildew control wasn't the perfect system--dusting could cause mite flare ups (almost impossible to control in an organic vineyard), and too much residue of wettable sulfur
could result in reduced odors in the wine.
If you catch mites early, keep them in check with a high-pressure water spray or a low-toxicity spray like wettable sulfur
If you have struggled with powdery mildew in previous seasons, applying wettable sulfur
spray during the first 6 inches of growth is an excellent practice, especially if rain occurs after bud break.
I treat mine not only with twice yearly sprayings of miscible oil (once in spring just as the buds begin to swell, another just after they have cracked open but before the petals have popped out), but I follow the oil on the second go-round with a spray of wettable sulfur
Apply wettable sulfur
at the highest rate right after bud break, before shoots have started to grow.
Numerous applications of wettable sulfur
pre-bloom seem to discourage the mites.
We saw leaf burn--but interestingly, not fruit burn--when we tank mixed with wettable sulfur