powder sulphur for grape leaves

Grape growers use powder sulfur as an organic fungicide. powder Sulfur, one of the few pathogens that affect grapes. It is applied when the grapes are small.  using a dusting device that blows the powder sulfur onto young grape plants. While sulfur makes an effective fungicide for some grapes.

Sulfur controls powdery mildew on grapevines under certain growing conditions. The presence of powdery mildew is recognized by blotchy red spots on dormant canes or white, web-like powder on leaves and fruit during the growing season. Powdery mildew grows most prolifically when temperatures range between 70 and 85 degrees Fahrenheit for a continuous period of six hours. Disease pressure increases when temperatures remain in the optimum range for powdery mildew three days in a row. Sulfur applications provide an organically acceptable and effective preventive measure for powdery mildew.

Powder sulphur  has been a consistent disease problem in all world vineyards for over a century. For nearly that long, elemental sulfur has been applied for its control. Agricultural bulletins dating to the 1890s describe the treatment schedule still in use today: regular applications of sulfur at 7- to 14-day intervals during the period of vine susceptibility. The interval may be adjusted for local conditions and grape variety. but no systematic method for determining the best timing has been previously presented. The past recommendations have led to under- or over-use of sulfur in years when environmental conditions are more or less favorable for epidemic spread.