Wounds are the entry point for GTD pathogens. Grapevines are pruned in order to optimize fruit quality and yield, which the exposed the host vascular system to airborne infections. Applying fungicides on pruning wounds is the best way to protect against GTD. Application should be done as early as possible after pruning under dry conditions because rain will wash off water-soluble fungicides and GTD fungal spores are airborne with free water. Fungicide should be applied mechanically with a tractor/sprayer or by hand as long as maximum wound coverage is achieved for optimal protection. Wounds remain susceptible for several weeks under cold and humid weather and several applications may be needed. Fungicide application on wounds are preventative strategies only, and should be implemented the first pruning year after the establishment of the vineyard and every year thereafter. These guidelines will significantly expand the longevity and productivity of vineyards.
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