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harvest time in a vineyard with collection boxes distributed along the rows of grape vines

UGA Extension contacts:
Phillip M. Brannen and Brett R Blaauw

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Cultural Practices
Diseases
Insects
Stage Management Activities
Dormant
CANE AND SPUR PRUNING should be completed during vine dormancy. Pruning is typically completed from December through March in Southeastern U.S. vineyards. Pruning sets the crop potential by retaining buds that are anticipated to bear fruitful shoots. Pruning is also used to remove dead or diseased grapevine wood.
Botryosphaeria canker Remove and destroy diseased canes and vines. Apply active fungicides after each day of pruning. Delay pruning as much as is practical.
Crown gall Remove dead vines.
Powdery Mildew Remove diseased canes through pruning during the dormant period. Spray lime sulfur at late dormancy.
Phomopsis Remove diseased canes through pruning during the dormant period. Spray lime sulfur at late dormant.
Anthracnose Remove and destroy diseased canes and vines during the dormant period. Spray lime sulfur at late dormancy.
Black Rot Remove mummified fruit and any diseased tissues during dormant pruning.
Ripe Rot Remove mummified fruit and any diseased tissues during dormant pruning. Infected fruit do not show symptoms until they ripen.
Bitter Rot Remove mummified fruit and any diseased tissues during dormant pruning.
Pierce’s Disease Cold winters reduce the impact of the disease, and winter pruning is important to remove infected canes. Destroy infected vines as soon as symptoms confirm the disease.
Mite Examine twigs using a hand lens for European red mite eggs, which are round and reddish orange.
Mealybug Examine under bark and twigs using a hand lens to identify mealy bugs. Scout for mealybugs by looking under the bark and near base of vine. Peel back loose bark on canes and look for the presence of grape mealybug crawlers.
Bud Swell
Any final pruning should be completed during bud swell. Bud swell alarms growers of impending bud break, a critical stage for frost protection and the first stage when green tissues are observed.
CANE AND SPUR PRUNING should be completed during vine dormancy. Pruning is typically completed from December through March in Southeastern U.S. vineyards. Pruning sets the crop potential by retaining buds that are anticipated to bear fruitful shoots. Pruning is also used to remove dead or diseased grapevine wood.
Botryosphaeria canker Remove and destroy diseased canes and vines. Apply active fungicides after each day of pruning. Delay pruning as much as is practical.
Powdery Mildew Remove diseased canes through pruning during the dormant period. Spray lime sulfur at late dormancy.
Phomopsis Remove diseased canes through pruning during the dormant period. Spray lime sulfur at late dormant.
Anthracnose Remove and destroy diseased canes and vines during the dormant period. Spray lime sulfur at late dormancy.
Grape Flea Beetle Check for feeding on unfolding leaves and buds from small, metallic blue-green beetles.
Climbing Cutworm Monitor bud feeding in early spring. If damage is present, look for cutworms under bark, on cordons, trunk, and at soil level.
Mite Examine twigs using a hand lens for European red mite eggs, which are round and reddish orange.
Mealybug Examine under bark and twigs using a hand lens to identify mealy bugs. Scout for mealybugs by looking under the bark and near base of vine. Peel back loose bark on canes and look for the presence of grape mealybug crawlers.
Bud Break
FROST DAMAGE is of concern once buds have broken. Air mixing (via wind machine) and delayed pruning are commonly implemented in an attempt to avoid frost injury to vine tissues.
SHOOT THINNING should occur when shoots are about 3-7” long, preferably as early as it’s possible to identify fruitful vs. non-fruitful shoots and before tendrils grab neighboring shoots. Shoots should be thinned to roughly 3-5 shoots per linear foot of cordon or cane.
SHOOT POSITIONING is more efficient when implemented before tendrils strongly grab to wires and neighboring shoots. Shoots should be positioned to accommodate the intended training system—doing so will maximize leaf exposure and limit leaf shading.
Pierce’s Disease Spray insecticides as soon as sharpshooter vectors are detected in the spring; early infections are more likely to result in mortality.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest.
Phomopsis Apply active fungicides as soon as green tissue emerges in the spring, and continue through veraison.
Anthracnose Apply active fungicides until berry touch. Berries are resistant at ~50 days after bud break as soluble solids rise above 5-7%.
Grape Flea Beetle Check for feeding on leaves and buds from small, metallic blue-green beetles and larvae that are brown with black dots.
Thrips On cool days after budbreak, open shoots or gently tap buds over white paper to check for thrips.
Sharpshooter/Leafhopper Place several double-sided yellow sticky traps per block and check traps weekly for sharpshooters/leafhoppers.
Prebloom
SHOOT THINNING should occur when shoots are about 3-7” long, preferably as early as it’s possible to identify fruitful vs. non-fruitful shoots and before tendrils grab neighboring shoots. Shoots should be thinned to roughly 3-5 shoots per linear foot of cordon or cane.
SHOOT POSITIONING is more efficient when implemented before tendrils strongly grab to wires and neighboring shoots. Shoots should be positioned to accommodate the intended training system—doing so will maximize leaf exposure and limit leaf shading.
Pierce’s Disease Spray insecticides as soon as sharpshooter vectors are detected in the spring; early infections are more likely to result in mortality.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest. During the period from prebloom to fruit set, the fruit is particularly susceptible to powdery mildew infection, but fruit infection is still a risk until approximately four weeks after bloom.
Phomopsis Apply active fungicides as soon as green tissue emerges in the spring, and continue through veraison. Fruit infections mainly occur between cluster emergence and early postbloom, and generally cease at green pea size.
Black Rot Apply active fungicides from bloom until veraison. Prebloom until six weeks postbloom is a critical infection period.
Bitter Rot Apply active fungicides from prebloom until harvest.
Sharpshooter/Leafhopper Place several double-sided yellow sticky traps per block and check traps weekly for sharpshooters/leafhoppers.
Bloom
SAMPLING involves collecting leaf tissues (petioles and/or blades) from opposite flower clusters at the bottom of the shoot. Tissues should be submitted for nutritional analyses, particularly in suspect cultivars or blocks. If needed, administer ground-applied fertilizer.
SHOOT POSITIONING is more efficient when implemented before tendrils strongly grab to wires and neighboring shoots. Shoots should be positioned to accommodate the intended training system—doing so will maximize leaf exposure and limit leaf shading.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest. During the period from prebloom to fruit set, the fruit is particularly susceptible to powdery mildew infection, but fruit infection is still a risk until approximately four weeks after bloom.
Phomopsis Apply active fungicides as soon as green tissue emerges in the spring, and continue through veraison. Fruit infections mainly occur between cluster emergence and early postbloom, and generally cease at green pea size.
Black Rot Apply active fungicides from bloom until veraison. Prebloom until six weeks postbloom is a critical infection period.
Botrytis Canopy management is very important. Highly active fungicides should be applied at early bloom to fruit set, just before berry touch, veraison, and two weeks after veraison through preharvest. Resistance is common, so rotate fungicide classes. Use Captan often during the season to further suppress this disease.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Mite Check leaves for chlorotic spots and bronzing. Using a hand lens, check the underside of the leaf along the leaf veins. Manage if more than 10 mites per leaf.
Fruit Set
LEAF REMOVAL should be implemented immediately after fruit set, optimally before the growth of BB-sized berries. Leaf removal at this early stage acclimates grapes to ambient radiation and temperatures, reducing the threat of severe fruit sunburn relative to leaf removal after berries reach pea size. Fruit zone leaf removal hastens cluster drying, improves spray penetration, and therefore offers better bunch rot control relative to unmanaged fruit zones.
SHOOT POSITIONING is more efficient when implemented before tendrils strongly grab to wires and neighboring shoots. Shoots should be positioned to accommodate the intended training system—doing so will maximize leaf exposure and limit leaf shading.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest. During the period from prebloom to fruit set, the fruit is particularly susceptible to powdery mildew infection, but fruit infection is still a risk until approximately four weeks after bloom.
Phomopsis Apply active fungicides as soon as green tissue emerges in the spring, and continue through veraison. Fruit infections mainly occur between cluster emergence and early postbloom, and generally cease at green pea size.
Black Rot Apply active fungicides from bloom until veraison. Prebloom until six weeks postbloom is a critical infection period.
Botrytis Canopy management is very important. Highly active fungicides should be applied at early bloom to fruit set, just before berry touch, veraison, and two weeks after veraison through preharvest. Resistance is common, so rotate fungicide classes. Use Captan often during the season to further suppress this disease.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Mealybug Signs of mealybugs are sticky honeydew and black sooty mold, and mealybugs are often associated with the presence of ants on the vines. For further evidence of mealybugs, check clusters for waxy, white residue between berries and on rachises.
Mite Check leaves for chlorotic spots and bronzing. Using a hand lens, check the underside of the leaf along the leaf veins. Manage if more than 10 mites per leaf.
Grape Berry Moth Flight periods of grape berry moth can be monitored using commercially available pheromone-baited traps. For the first three flights, expect 50% emergence at 187, 869, and 1094 degree days above a base of 47 °F after first male catch.
Grape Berry Moth Monitor grape berry moth using pheromone-baited traps and look for webbing in the clusters when berries are small—larvae will web multiple berries together.
BB-sized Fruit
LEAF REMOVAL should be implemented immediately after fruit set, optimally before the growth of BB-sized berries. Leaf removal at this early stage acclimates grapes to ambient radiation and temperatures, reducing the threat of severe fruit sunburn relative to leaf removal after berries reach pea size. Fruit zone leaf removal hastens cluster drying, improves spray penetration, and therefore offers better bunch rot control relative to unmanaged fruit zones.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest. Fruit infection is still a risk until approximately four weeks after bloom.
Phomopsis Apply active fungicides as soon as green tissue emerges in the spring, and continue through veraison. Fruit infections mainly occur between cluster emergence and early postbloom, and generally cease at green pea size.
Black Rot Apply active fungicides from bloom until veraison. Prebloom until six weeks postbloom is a critical infection period.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Mite Check leaves for chlorotic spots and bronzing. Using a hand lens, check the underside of the leaf along the leaf veins. Manage if more than 10 mites per leaf.
Grape Berry Moth Monitor grape berry moth using pheromone-baited traps and look for webbing in the clusters when berries are small—larvae will web multiple berries together.
Japanese Beetle and Green June Beetle Check for shiny green- and copper-colored beetles. Feeding skeletonizes leaves and is concentrated in the upper part of the vine canopy. The large, green June beetles may feed on the fruit. Severe feeding by beetles after veraison can have significant impact on fruit quality.
Pea-sized Fruit
CANOPY HEDGING is typically first necessary when berries reach pea size. Hedging should be implemented repeatedly as needed through veraison, after which it is often not required. To ensure optimal canopy sunlight and spray penetration, lateral shoots should be hedged from the side of primary shoots, and primary shoots should be hedged at their apex before they bend over and shade the canopy.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Black Rot Apply active fungicides from bloom until veraison. Prebloom until six weeks postbloom is a critical infection period.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Mite Check leaves for chlorotic spots and bronzing. Using a hand lens, check the underside of the leaf along the leaf veins. Manage if more than 10 mites per leaf.
Grape Berry Moth Monitor grape berry moth using pheromone-baited traps and look for webbing in the clusters when berries are small—larvae will web multiple berries together.
Japanese Beetle and Green June Beetle Check for shiny green- and copper-colored beetles. Feeding skeletonizes leaves and is concentrated in the upper part of the vine canopy. The large, green June beetles may feed on the fruit. Severe feeding by beetles after veraison can have significant impact on fruit quality.
Berry Touch
CANOPY HEDGING is typically first necessary when berries reach pea size. Hedging should be implemented repeatedly as needed through veraison, after which it is often not required. To ensure optimal canopy sunlight and spray penetration, lateral shoots should be hedged from the side of primary shoots, and primary shoots should be hedged at their apex before they bend over and shade the canopy.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Anthracnose Apply active fungicides until berry touch. Berries are resistant at ~50 days after bud break as soluble solids rise above 5-7%.
Botrytis Canopy management is very important. Highly active fungicides should be applied at early bloom to fruit set, just before berry touch, veraison, and two weeks after veraison through preharvest. Resistance is common, so rotate fungicide classes. Use Captan often during the season to further suppress this disease.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Mealybug Signs of mealybugs are sticky honeydew and black sooty mold, and mealybugs are often associated with the presence of ants on the vines. For further evidence of mealybugs, check clusters for waxy, white residue between berries and on rachises.
Mite Check leaves for chlorotic spots and bronzing. Using a hand lens, check the underside of the leaf along the leaf veins. Manage if more than 10 mites per leaf.
Grape Root Borer Monitor flight activity of grape root borer using commercially available pheromone-baited traps and examine soil near base of vine for empty pupal skins.
Grape Berry Moth Monitor grape berry moth using pheromone-baited traps and look for webbing in the clusters when berries are small—larvae will web multiple berries together.
Japanese Beetle and Green June Beetle Check for shiny green- and copper-colored beetles. Feeding skeletonizes leaves and is concentrated in the upper part of the vine canopy. The large, green June beetles may feed on the fruit. Severe feeding by beetles after veraison can have significant impact on fruit quality.
Bunch Closure
LEAF REMOVAL amounting to a “cleanup pass” may be required around bunch closure to remove foliage that has regrown into the fruit zone.
CANOPY HEDGING is typically first necessary when berries reach pea size. Hedging should be implemented repeatedly as needed through veraison, after which it is often not required. To ensure optimal canopy sunlight and spray penetration, lateral shoots should be hedged from the side of primary shoots, and primary shoots should be hedged at their apex before they bend over and shade the canopy.
Downy Mildew Leaves are always susceptible to infection. Fruit, rachises, and pedicels are resistant at about four weeks after bloom. Apply active fungicides in rotation. Fungicide resistance, particularly to the strobilurin fungicides, is prevalent.
Botrytis Canopy management is very important. Highly active fungicides should be applied at early bloom to fruit set, just before berry touch, veraison, and two weeks after veraison through preharvest. Resistance is common, so rotate fungicide classes. Use Captan often during the season to further suppress this disease.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Mealybug Signs of mealybugs are sticky honeydew and black sooty mold, and mealybugs are often associated with the presence of ants on the vines. For further evidence of mealybugs, check clusters for waxy, white residue between berries and on rachises.
Sharpshooter/Leafhopper Place several double-sided yellow sticky traps per block and check traps weekly for sharpshooters/leafhoppers.
Grape Berry Moth Monitor grape berry moth using pheromone-baited traps and look for webbing in the clusters when berries are small—larvae will web multiple berries together.
Japanese Beetle and Green June Beetle Check for shiny green- and copper-colored beetles. Feeding skeletonizes leaves and is concentrated in the upper part of the vine canopy. The large, green June beetles may feed on the fruit. Severe feeding by beetles after veraison can have significant impact on fruit quality.
Veraison
BIRD NETTING should be placed immediately upon berry softening and color change to prevent bird depredation. Do not underestimate the amount of crop that can be damaged or removed by wildlife.
SAMPLING involves removing leaf tissues from fully expanded leaves at the tops of primary shoots for nutritional analyses. Growers can choose to sample specific vines or regions if deficiency symptoms are evident at veraison.
SCOUTING for nutrient disorders and systemic infections should occur throughout the entire post veraison to preharvest period, when vines become stressed and are allocating resources away from leaves to ripening fruit. Red leaves are indicative of nutrient disorders but may can also indicate systemic infections. If time is limited, flag vines and plan to tend to them after harvest.
CANOPY HEDGING is typically first necessary when berries reach pea size. Hedging should be implemented repeatedly as needed through veraison, after which it is often not required. To ensure optimal canopy sunlight and spray penetration, lateral shoots should be hedged from the side of primary shoots, and primary shoots should be hedged at their apex before they bend over and shade the canopy.
Phomopsis Apply active fungicides as soon as green tissue emerges in the spring, and continue through veraison.
Black Rot Apply active fungicides from bloom until veraison. Prebloom until six weeks postbloom is a critical infection period.
Botrytis Canopy management is very important. Highly active fungicides should be applied at early bloom to fruit set, just before berry touch, veraison, and two weeks after veraison through preharvest. Resistance is common, so rotate fungicide classes. Use Captan often during the season to further suppress this disease.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Sour Rot Late-season fruit injury and drosophila invasion are critical to establishment and spread of this disease caused by yeasts and acetobacter bacteria. Sour rot generally does not start prior to 10 brix or veraison.
Sharpshooter/Leafhopper Place several double-sided yellow sticky traps per block and check traps weekly for sharpshooters/leafhoppers.
Japanese Beetle and Green June Beetle Check for shiny green- and copper-colored beetles. Feeding skeletonizes leaves and is concentrated in the upper part of the vine canopy. The large, green June beetles may feed on the fruit. Severe feeding by beetles after veraison can have significant impact on fruit quality.
Spotted Wing Drosophila (SWD) Berries become attractive to SWD at 15 brix. SWD presence in vineyards can be monitored with homemade traps, commercial lures, and larvae in fruit. Control decisions should be influenced by the farm’s history of SWD infestations.
Yellow Jacket The key to yellow jacket management is keeping the fruit intact, for example, by minimizing disease, fruit splitting, and bird damage. Scout for wasp nests in the vineyard, in nearby buildings, or in nearby trees. Manage through nest removal or traps.
Preharvest
BIRD NETTING should be placed immediately upon berry softening and color change to prevent bird depredation. Do not underestimate the amount of crop that can be damaged or removed by wildlife.
SCOUTING for nutrient disorders and systemic infections should occur throughout the entire post veraison to preharvest period, when vines become stressed and are allocating resources away from leaves to ripening fruit. Red leaves are indicative of nutrient disorders but may can also indicate systemic infections. If time is limited, flag vines and plan to tend to them after harvest.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest.
Botrytis Canopy management is very important. Highly active fungicides should be applied at early bloom to fruit set, just before berry touch, veraison, and two weeks after veraison through preharvest. Resistance is common, so rotate fungicide classes. Use Captan often during the season to further suppress this disease.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Sour Rot Late-season fruit injury and drosophila invasion are critical to establishment and spread of this disease caused by yeasts and acetobacter bacteria. Sour rot generally does not start prior to 10 brix or veraison.
Sharpshooter/Leafhopper Place several double-sided yellow sticky traps per block and check traps weekly for sharpshooters/leafhoppers.
Japanese Beetle and Green June Beetle Check for shiny green- and copper-colored beetles. Feeding skeletonizes leaves and is concentrated in the upper part of the vine canopy. The large, green June beetles may feed on the fruit. Severe feeding by beetles after veraison can have significant impact on fruit quality.
Spotted Wing Drosophila (SWD) Berries become attractive to SWD at 15 brix. SWD presence in vineyards can be monitored with homemade traps, commercial lures, and larvae in fruit. Control decisions should be influenced by the farm’s history of SWD infestations.
Yellow Jacket The key to yellow jacket management is keeping the fruit intact, for example, by minimizing disease, fruit splitting, and bird damage. Scout for wasp nests in the vineyard, in nearby buildings, or in nearby trees. Manage through nest removal or traps.
Harvest
HARVEST decisions are cultivar-, region-, and site- specific. Use grape chemistry analyses, sensory perception (taste, color, fruit integrity), intended wine style, and predicted weather patterns to make judicious harvest decisions.
Powdery Mildew Apply active fungicides as soon as green tissue emerges in the spring, and continue through postharvest.
Ripe Rot Apply active fungicides from bloom until harvest.
Bitter Rot Apply active fungicides from prebloom until harvest.
Pierce’s Disease Destroy infected vines as soon as symptoms confirm the disease.
Spotted Wing Drosophila (SWD) Berries become attractive to SWD at 15 brix. SWD presence in vineyards can be monitored with homemade traps, commercial lures, and larvae in fruit. Control decisions should be influenced by the farm’s history of SWD infestations.
Yellow Jacket The key to yellow jacket management is keeping the fruit intact, for example, by minimizing disease, fruit splitting, and bird damage. Scout for wasp nests in the vineyard, in nearby buildings, or in nearby trees. Manage through nest removal or traps.


Published by University of Georgia Cooperative Extension. For more information or guidance, contact your local Extension office.

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