Grape Vine Problems

Healthy Growth

• Healthy grape vines are woody and coil themselves around a support structure. These vines feature a smooth bark and produce round or oblong fruits that are widely cultivated for a variety of culinary uses. This plant grows well in a variety of well-drained soils as long as they aren't too fertile.

Grape Leafroll Disease

• One of the most common diseases to infect grapevines is leafroll disease. This virus causes the grapevine to display discolored leaves that appear red in color with prominent veins. As the disease progresses, it stunts the growth of the vine and decreases the fruit production. This disease is most common in grapevines yielding red grapes and can decrease the amount of harvestable fruit by 30 percent to 50 percent.

Controlling Grape Leafroll

• Unfortunately, the only current way to control this disease is to test the vine before it is planted to ensure that the disease is not present. There is no cure for infected grapevines. Once introduced to the landscape, the disease can spread to other vines. It is imperative that diseased vines not be grafted for propagation. There are no vines that are resistant to grape leafroll disease.

Grape Cane Borer

• The grape cane borer is a type of beetle that is sometimes referred to as an apple twig borer. This pest damages grapevines throughout Europe and North America. One generation of cane borers feeds on the grapevine in a single season. The presence of the pest can cause the canes of the grapevine to become wakened as a result of the holes bored in the cane by the beetle. Vines damaged by this pest have 30 percent to 50 percent less harvestable fruit than healthy plants.

Controlling Grape Cane Borers

• If the infestation of the beetle is minimal, simply removing infected areas can prove effective in managing the problem. In more severe cases, insecticides available at local garden centers may aid in controlling the problem. All insecticides should be applied according to the manufacturer's instructions and sprayed in the spring and in the fall for the best results.

Black Rot

• Black rot is a fungal disease caused by Guignardia idwellii. Vines with this disease may feature small spots that are reddish-brown in appearance and less than 1/4 inch in diameter. The fungus that causes the disease overwinters in the soil and grows rapidly in moist, warm conditions. Left untreated, the disease will cause shriveled grapes, defoliation and cane infections. Fortunately, fungicides available at garden centers are effective in controlling the disease. Apply all fungicides according to the manufacturer's instructions.

Grape Berry Moth

• The grape berry moth is a common problem in northeastern vineyards. This small moth lays its eggs on the berries of the grape vine. Larvae then feed on the berries, webbing three to 10 of them together as they do so. Vines that are infected with this disease will have discolored, purple berries with a small hole where the larvae entered the fruit. Inspect the plant starting in June and apply insecticides as a method of control. Insecticides should be applied according to the manufacturer's instructions.