Insects, Viral and Fungal Diseases

In the last issue of WineMaker we concerned ourselves with the “common” diseases of backyard viticulture. As the flu and common cold attack the human body, powdery mildew and rot attack vineyards. As we discussed in the previous article, vigilant prevention and careful canopy management are vital to keeping your vines free from mildew and botrytis. Well-timed applications of sulfur, or a mixture of sulfur and copper, can do wonders to alleviate the potential damage of mildew and rot. The diseases covered in this article will be more difficult to control and recognize. Many can be misdiagnosed and mistreated — so examine with a critical eye, lest you make hasty decisions. This article is not intended to teach everyone all there is to know about spotting a disease, diagnosing it, and solving the problem. Instead, I hope this will serve as a short primer, describing a few rare diseases that show up in vineyards. Also, this article should get you some of the necessary tools for spotting a problem, and finding a professional to confirm your suspicion. This professional should