By Bonnie L. Grant
Grapevines are tough plants that thrive after being severely cut back, re-bloom after snowy winters and produce masses of fruit even when neglected. That said, there are several pest, cultural and grapevine diseases, which can minimize the vigor of these plants.
Rarely do grapevine pests or disease kill a vine, but it help to have information on preventing problems in grapes so the harvest will be robust. Learn how to take care of grapevine issues and be prepared to apply treatments as soon as they are noticed.
Preventing Problems in Grapes
Grapevines have specific cultural requirements. When these are met, most vines perform beautifully with few problems. Grapes perform best if grown in well-drained soil with plenty of organic amendment. Most grape varieties are hardy in USDA zones 3 to 8, but some prefer cooler weather, while others need a longer warmer season.
Annual pruning is key to preventing problems in grapes. Train young canes to just one strong leader, with peripheral shoots coming off that and tied to a trellis.
There are many other grapevine diseases to be vigilant and prepared for treating grapevine problems, including both fungal and bacterial diseases.
Fungal – The most common diseases of grapes are fungal. Much of these are controlled with good cultural control. Old plant material can harbor the fungal spores in soil even over the winter, so it is essential to clean up around the vines after pruning. Black spot, powdery mildew and anthracnose are just a few of the common fungal diseases. They most commonly affect the foliage with spotting or a coating, but may occasionally threaten twigs and terminal tissues. The fungus reduces the plant’s effectiveness at gathering solar energy and can cause leaf loss.
Bacterial – Bacterial grapevine diseases are also common in the plants. Where vines are growing in an orchard situation, the disease can be devastating as it passes from vine to vine. The home gardener is unlikely to experience this type of widespread damage. Crown gall disease in grapevines affects the roots and lower stems. The disease causes black galls and requires soil fumigation or solarization to kill the bacteria.
The sweet, succulent fruit is a magnet for rodents, insects and especially birds. Bird nets can help protect the fruit from complete annihilation by hungry animals.
Boring insects can seriously harm the health of your grapevine as well. Treating grapevine problems of this sort usually requires a pesticide registered for use on edible plants. Sevin is one recommended by the Texas A & M Agriculture department.
How to Take Care of Grapevine Issues
Treating grapevine problems starts with identification of the problem. There are so many potential pests and grapevine diseases that it might be helpful to collect a leaf or twig sample and take it into your county extension office for identification.
Once you know what you are dealing with, it is easier to decide how to proceed. Consider the difference between organic and inorganic. Organic fungicides and insecticides will be the choice for a natural gardener. Inorganic treatments are effective and the common choice for large-scale producers or gardeners that just want the job done.
No matter which treatment you choose, always read the label and apply in the manner recommended by the manufacturer.