Lime sulfur is a common fungicide applied to grapevines during the growing season. Lime sulfur is approved for organic production systems and is generally believed that the different pathogens it is used against cannot become resistant. Because lime sulfur contains no pesticides, it is safe for use on grapes.
Lime sulfur was first mixed by Grison, the head gardener at the vegetable houses of Versailles, France, in 1851. Grison was searching for a solution for fungal infections on his vegetables -- lime sulfur worked so well it became a commonly used mixture referred to as "Grison Liquid." Lime sulfur works by disrupting the transfer of electrons inside the fungus and causing the sulfur in the solution to transform into highly toxic hydrogen sulfide. Sulfur alone can also cause reactions on the plants it is used to protect, lime helps reduce the sulfur's tendency to make plants overly sensitive to the sun.
Grapes Sensitive to Sulfur
Despite the tempering advantages of lime on sulfur spray, some grapes are highly sensitive to it. On these plants, don't use lime sulfur until absolutely necessary or dilute it before applying. "Chambourdin," "Chancellor," "Concord," "DeChaunac," "Foch," "Ives" and "Rougeon" are varieties sensitive to lime sulfur spray. Sensitivity has not yet been determined in "Einset Seedless," "Frontenac," "Frontenac Gris," "La Crescent," "Marquette" and "Vanessa."
Lime sulfur is generally effective against foliar fungus problems. Lime sulfur is recommended especially for diseases caused by phomopsis cane and leafspot (Phomopsis viticola), powdery mildew (Erisphe necator) and measles caused by both Togninia spp. and Phaeoacremonium spp. When combined with cultural controls that encourage dry leaf and fruit surfaces, lime sulfur can provide considerable protection against serious loss due to fungus.
When to Spray
Lime sulfur is traditionally considered a dormant season spray, but you can also use it during the growing season. In the dormant season, apply it when temperatures are above freezing, but before leaves are present. During the growing season, use a more diluted lime sulfur mix and spray early in the morning or in the cool of late afternoon to avoid injuring the leaves. Do not apply lime sulfur when the weather is dry and temperatures are above 80 degrees Fahrenheit.
- University of Nebraska Lincoln Extension: Lime-Sulfur: A Fungicide Used to Control a Variety of Diseases
- New York State Integrated Pest Management Program: 2011 Production Guide for Organic Grapes
- University of California Statewide Integrated Pest Management Program: Fungicide Efficacy and Treatment Timing for Grapevines
- University of California Statewide Integrated Pest Management Program: Phomopsis Cane and Leafspot on Grape
- University of California Statewide Integrated Pest Management Program: Powdery Mildew on Grape
- University of California Statewide Integrated Pest Management Program: Guidelines for Measles (Esca) on Grapes
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