UGA Extension Viticulture Blog

Changes to Recommended Downy Mildew Materials

Presidio is no longer registered for grape downy mildew management.  This is unfortunate, but Valent confirmed this information. Presidio will be removed from the SRSFC IPM guide.  You can use existing stocks of Presidio, so no worries if you have it on hand at this time. Ranman has confirmed activity against downy mildew, and it will be added to the newly updated IPM guide.  Several studies have shown that Ranman works particularly well when combined with a phosphonate material, such as ProPhyt or others.  However, as always, review the label carefully and test physical compatibility with other materials in a tank mix (jar test) and apply to a small section of your vineyard (by grape species/variety) to make sure no phytotoxicity occurs. Ranman should not be mixed with a surfactant; this is noted on the label.