Vineyard Sanitation Reminders for the Dormant Season
As we enter February, our thoughts begin to think of the warm and sunny days ahead this spring. Before we know it, May will be here, and the growing season will be in full swing! Over these next few months, there are several vineyard sanitation tasks that you can start now to prepare your vineyard for a healthy and productive season.
Just like you might take vitamin C to prevent a cold, cleaning your vineyard of diseased plant material can prevent future infections and improve overall plant health. It is tedious work, but the time you spend removing diseased tissues now will protect your crop this season.
Black rot (Guignardia bidwellii) is a disease many vineyards encountered last season. The fungus is native to North America and can become a big problem in warm and humid conditions. Black rot infects the leaves, berries, and canes of grapevines. During the growing season, black rot can be easily identified by tan spots on the leaf surface. Overtime, you will start to observe small, black bumps forming on the lesions – this is where spores are produced (Figure 1). This is an important source of inoculum during the growing season. However, the black rot fungus can also form these spore-producing structures on the mummies (shriveled and rotted fruit; Figure 2) and on dormant canes.During the winter, infected canes and mummies should be the target of your sanitation program, because if left on the vine, they will serve as a source of inoculum for the upcoming season.
Removing diseased tissue is a simple and easy way to improve the health of your vineyard. Grab your pruners and remove any mummified fruit from the canopy. These mummies can be left on the ground, but for the highest level of sanitation, removal from the vineyard is recommended. Mummies left on the ground can be buried with cultivating or mulching. This is especially critical for organic vineyards, where black rot is considered the “Achilles’ heel”, due to the limited OMRI-listed chemistries available to manage this disease. Leaving mummies in the canopy will significantly increase the risk of infection of young, emerging tissues as buds break in the spring. Infected canes should also be removed during this time.
Removing cane lesions and mummies also aids in disease management of Phomopsis cane and leaf spot (Figure 3; Phomopsis viticola) as well as Anthracnose (Figure 4; Elsinöe ampelina). Like black rot, these pathogens can overwinter in dormant canes or mummies and wait for warmer temperatures and rainfall in the spring to begin sporulation and infection. Don’t forget to pair your sanitation practices with well-timed fungicide sprays early in the season.
Figure 3: Phomopsis fruiting bodies on dormant cane. 
Figure 4: Old anthracnose lesions on dormant cane