Grapevine issues

Grapes, whether eaten processed, fresh or dried into raisins, contain lots of nutrients including vitamins C and B, calcium and iron. Based on the species and cultivar, strawberries develop in a variety of areas around the world and throughout U.S. Department of Agriculture plant hardiness zones 4 to 11. Whether the fruits are purple, green or red, grapevines are susceptible to disease and pest problems.


Grapevines require spacious and healthy growing environments. Foliage, vines and fruits can become stunted if they don’t grow in full sunlight. They need to have at least 150 days without frost or temperatures below 32 degrees Fahrenheit. Grapevines require good air flow and well-draining soil or they may be susceptible to disease and infestation. Although particular needs vary by species and cultivar, fruiting grapevines have to have at least 2,000 “growing degree days” over 50 F, notes Cornell University.

Fungal Diseases

Fungal diseases affect grapevines, fruits and leaves — especially during summertime heat and heat. Black or bunch rot (Botrytis cinera) develops on flowers, foliage and fruits, causing grayish brown layers of fungal spores. Powdery mildew impacts green tissues, turning stems and leaves grayish-white before darkening. Stunted buds, leaves and flowers cause pulp to break the grapes’ skin. Downy mildew produces yellow-green lesions on leaves, which afterwards drop in the vine. With grape leafroll disease, most notable in red fruit cultivars, veins stay green but leaves curl while turning red. The disease stunts vines, foliage and fruits. No cure exists for leafroll, so planting disease-free vines is imperative to developing a healthy grape crop.

Pest Problems

Grapevines attract a number of pests, including allergens;; grape berry moths; Japanese grape flea and other sorts of beetles; cane and root borers; mealybugs; along with grape phylloxera. Usually in June and July, older insects chew grape leaves, vines, canes and developing fruitsand vegetables. Grape and Japanese flea beetles may severely harm foliage and young buds. Leafhoppers are tiny insects that leap sideways onto foliage, leaving spots that might cause leaves to fall. Grape berry moths lay eggs that feed on young fruits, typically from June to harvest. Mites live on grape leaves, the bugs might make a bronzing of foliage that retains leaves from photosynthesizing. Other insects — cane gallmakers and girdlers — create leaf scars or take damage. Insecticides can be pricey, notes Purdue University Extension, but they might control some infestations.

Chemical Injury

Herbicides can hurt cultivated grapevines, fruits and leaves. Two, 4-D herbicide, says Purdue University, is often used on crops and vegetative sites. Although use might be far from growing grapevines, floating chemicals can cause symptoms much like those from disease or insects. Wind direction and airspeed of floating chemicals can have a great effect on landscapes and gardens. Grapes are most vulnerable to herbicide damage in spring and early summer. Chemical injury symptoms include misshapen, stunted leaf and leaf growth and fragile, parallel running veins.

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