When used properly Captan is a safe and effective fungicide that plays an important role in grape disease control and fungicide resistance management, but it is crucially important to never apply Captan mixed with oil or close in time to the application of any oils. The active ingredient in Captan cannot easily penetrate into the plant, but when it does it can be very toxic, especially to grapes. Injury from this type of spray combination has been reported in blueberries and there are many anecdotal reports of less severe phytotoxicity in other fruit crops. By comparison, the damage to grapes can be very severe and the symptoms include leaf necrosis, longitudinal stem splitting and vine death (Fig. 1, 2, 3). Sadly, experience has shown that under the appropriate conditions a single spray of Captan with an emulsifiable concentrate insecticide can kill an entire vineyard. [Read more…]