Macronutrient - Sulfur (S) is essential for the production of proteins by the plant. It works in the development of enzymes and vitamins as well as in chlorophyll formation. Other roles of sulfur include cold hardiness development, seed production and root growth.

Sources - Generally found in soils, as impurities in some fertilizers, gypsum and in rain where acid rain is experienced.

Fungicides - Many of the "organic" fungicides are based on sulfur compounds.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.