Grape Insects

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  • Ants

    A column of ants on a vine during the summer may be tending mealybugs because ants feed on the secreted honeydew. Ants can become pests during harvest, when ripe berries are a source of sugar, and they can become a hazard for handpickers. They rarely require control and typically affect a small area of a vineyard.

  • Banded grape bug

    The banded grape bug has piercing-sucking mouthparts that it inserts into plant tissue to suck out plant sap. It completes one generation per year on grapes and is active in vineyards from shortly after bud break to early July. It spends most of the year as an egg, which is the overwintering stage. Eggs are laid in crevices on second-year wood and vine trunks. They hatch when shoots are approximately 2 to 5 inches (5 to 13 cm) long. The nymphs then begin feeding on shoot tips and newly emerged leaves. Feeding is concentrated in the stalks of individual florets, the buds and the cluster stem. Nymph development takes about 3 weeks, with adults appearing in early June.

  • Brown marmorated stink bug

    Brown marmorated stink bug adults are 3/4-inch long and shield-shaped, with mottled brown coloration on the upper and lower surface. They can be distinguished by lighter bands on antennae and they have darker bands on the membrane part at the rear of the front pair of wings. On the head, there are patches of copper or bluish-metallic depressions. Eggs are light green and are laid in groups of 20 to 30 on the underside of leaves or on clusters. There are five nymphal stages. This pest can contaminate harvested clusters and its secretions can lead to tainted juice.

  • Climbing cutworm

    Climbing cutworms are large, smooth caterpillars measuring 30 to 40 mm when fully grown. The head capsule is usually dark and the body is dull gray-brown, marked with dots or stripes, and curled when disturbed. The larvae overwinter in the soil of the vineyard floor and become active in spring when vine buds begin to expand. Larvae feed on young buds at night, hiding in the soil beneath the vines during the day. Cutworms are mainly a pest in areas with sandy soils and in vineyards with weeds under the vines.

  • European red mite

    Adult female European red mites are less than 0.5 mm and dark red with eight legs. Adult males are smaller than the females and have a pointed abdomen. Males are usually dull green to brown. Mites hatch in the spring from tiny, spherical eggs laid around cane nodes and under loose bark. These eggs can be detected by scouting in early spring. Although several generations can occur each season, populations rarely increase enough to cause significant damage because predatory mites usually prevent their growth.

  • Fruit flies

    Fruit flies lay eggs near the surface of fermenting berries. Eggs take only 30 hours to hatch, and larvae develop in fermenting material. They feed near the surface, mostly on yeast, for 5 to 6 days and go to drier places to pupate. The life cycle may be completed within 8 to 10 days at 85 F (29 C). Timely harvesting can help prevent fruit fly outbreaks in the vineyard.

  • Gallmakers on leaves

    Many galls of various shapes occur on grapevines as a result of attack by small flies (gall midges). Galls can occur on leaves, tendrils and blossom buds. Numerous species of gall midges attack grape. Galls are formed by larvae of small cecidomyiid flies, which lay their eggs into the leaf. There may be one to three generations per year. The life cycle begins with eggs laid within the unfolding buds or shoot tips. Orange, maggotlike larvae hatch from these eggs and enter the vine tissue. As the larvae feed, galls form around them.

  • Grape berry moth

    Grape berry moth spends the winter as a pupa in leaf litter in and around vineyards. First generation adults emerge from the pupae before bloom. Male and female moths mate and then females lay circular, flat eggs directly onto the cluster around bloom. The eggs can be difficult to find because of their small size (approximately 1 mm diameter). Their shiny exterior can be used to detect them, especially with a hand lens. Eggs parasitized by wasp parasites turn black. Larvae hatch from the eggs in 3 to 6 days, depending upon temperature, and feed on the cluster until they have developed to full size. Larvae of the first generation feed on young grape clusters and may remove sections of clusters. Then, when berries are formed, the young larvae burrow into the fruit. Webbing and larvae are visible in the small clusters during and after bloom. Damage from redbanded leafroller can be mistaken for grape berry moth at this time, so it is important to identify the larvae to determine the appropriate management strategy.

  • Grape cane gallmaker

    The adult is a dark brown snout beetle about 1/8 inch (4 mm) long that looks like the grape cane girdler. The legless grub is white with a brown head and slightly larger when full grown.

  • Grape cane girdler

    The grape cane girdler is a black snout beetle. In late spring, the female makes holes encircling the cane and lays her eggs in the holes. She then encircles the cane with another series of punctures a few inches below the first girdle. The leg-less grub is white with a brown head and feeds in the cane pith between the girdles. After larvae complete their development, they pupate. Adults appear in late summer and hibernate over the winter.

  • Grape erineum mite

    This very small mite cannot be seen without magnification. It overwinters under the bark of 1-year-old canes.

  • Grape flea beetle

    The grape flea beetle (or steely beetle) is a shiny, metallic dark blue. It may jump when disturbed. Larvae are yellow-brown with a dark head and feed on clusters and leaf surfaces. The insect overwinters as an adult. This stage feeds directly on young buds, beginning when conditions warm in the spring. Vineyard borders adjacent to woods or other protected areas are most affected.

  • Grape leafhopper

    All leafhopper species feed on the undersides of leaves, puncturing cells and sucking out the contents. In general, juice grape (labrusca) varieties are much more tolerant of leafhoppers than hybrid or vinifera varieties. Grape leafhopper adults are orange-yellow with some dark spots and yellow lines on the wings and are about 1/8 inch long. Grape leafhopper has 1.5 to 2 generations per year, with peak abundance of adults occuring in late July and again in late August. Adults overwinter in leaf litter in or around vineyards and feed on weeds as temperatures exceed 60o F (16o C) in the spring. After mating, they move to young grape foliage in late May and early July to lay clear, crescent-shaped eggs inside the leaves. First generation eggs hatch in mid- to late June, and the flightless nymphs take a month to develop into adults. Cold, wet springs and winters are damaging to leafhoppers Sampling for grape leafhopper In labrusca vines, growers can sample for grape leafhopper in the third week of July to determine the need for management. Examine 100 leaves across two edge and two interior vineyard sites. At each site, inspect five leaves (leaves 3 to 7) on one shoot of five vines to determine whether the leaves are showing any white/yellow stippling on the upper leaf surface. If more than 10 leaves of the 100 show damage, apply an appropriate control for the leafhoppers. If populations are only at the vineyard edges, consider area-specific management. Insecticides applied for grape berry moth may control grape leafhopper as well.

  • Grape mealybug

    Adults are soft, oval, flat, distinctly segmented and covered with a waxy layer that extends into spines along the body margin and the posterior end. The pinkish body is visible through the powdery wax. Mealybugs are most commonly found in the crevices of the wood or on berries near the trunk. They may be tended by ants that feed on honeydew.

  • Grape phylloxera

    Phylloxera are small, yellow, aphidlike insects that live on vine roots and leaves. The root form stunts growth of susceptible vines and can kill them. In the eastern United States, foliar damage is seen on wild grape, labrusca and some vinifera vineyards as raised galls on the undersides of leaves. The root form of this pest prefers vines growing in heavy clay soils. Labrusca grapes can tolerate phylloxera feeding on roots, particularly in well-watered vineyards.

  • Grape root borer

    Adult grape root borers are clearwing moths with a dark brown body and yellow-orange bands on the abdomen. Moths are active during the day and are seen on vines in July. The female moths lay up to 300 eggs on or near the vine, and newly hatched larvae crawl into the soil and vine roots. Larvae feed on the roots for up to 2 years (perhaps longer), moving to larger roots as they grow. Damaged vines have reduced vigor and may eventually die. This species is found in much of the eastern United States but is more damaging in southern states.

  • Grape rootworm

    This beetle is 6 mm long and light brown with yellow hairs. It feeds on grape foliage as an adult, making a chainlike damage pattern. Immature stages feed on grape roots. Infestations that go untreated for many years can lead to vineyard decline. Grape rootworm adults begin appearing in vineyards in mid- to late May and then lay eggs on the vine trunks. Larvae later crawl into the soil and attach themselves to grape roots, remaining there for 1 to 2 years while completing their development. Larvae eat small roots and bore into larger ones.

  • Hornworm

    Hornworms (sphingid larvae) are found feeding on leaves in vineyards. Larvae may be brown or green with spots on the sides of the body and a distinctive “horn” on the rear end. The larvae can grow to 5 inches (12 cm) long, and they feed voraciously during development. Because of this, hornworms are more of a concern in young vineyards with limited leaf area. Larger vines can usually tolerate some leaf area loss from their feeding.

  • Japanese beetle

    Japanese beetles can be present from June through September. Beetles lay eggs underground in grassy areas near vineyards, preferring soil with moisture.This pest can be a problem particularly in new vineyards using grow tubes. Frequent monitoring is required to reduce the risk of severe damage.

  • Multicolored Asian lady beetle

    This insect searches for sugar resources and tight spaces to prepare for overwintering. These characteristics may attract them to ripe grape clusters during harvest. Grapes or juice may be contaminated if beetles are crushed with fruit.

  • Potato leafhopper

    All leafhopper species feed on the undersides of leaves, puncturing cells and sucking out the contents. In general, juice grape (labrusca) varieties are much more tolerant of leafhoppers than hybrid or vinifera varieties. The adult potato leafhopper is pale to bright green and about 1/8 inch long. Adults are very active, jumping, flying or running when disturbed. The immature forms, or nymphs, are pale green and wingless. They run forward, backward or sideways when disturbed. The potato leafhopper does not overwinter north of the Gulf states. Adults migrate north each spring on southerly winds and are deposited during May and June in spring rains. Potato leafhoppers can be very destructive on hybrid or vinifera varieties that are sensitive to the saliva they inject while feeding. Feeding is concentrated on young tissues near the shoot tips. On sensitive varieties, only a few adults are needed to cause leaf yellowing and cupping or shortened shoot internodes. This insect is typically a minor pest in labrusca grapes.

  • Rose chafer

    The rose chafer is a light tan beetle with a darker brown head and long legs. It is about 12 mm long. There is one generation per year. Adults emerge from the ground during late May or June, near grape bloom time, and live for 3 to 4 weeks. Females lay groups of eggs just below the surface in grassy areas of sandy, well-drained soils. The larvae (grubs) spend the winter underground, move up in the soil to feed on grass roots and then pupate in the spring. A few weeks later, they emerge from the soil and disperse by flight. Male beetles are attracted to females and congregate on plants to mate and feed.

  • Spotted wing Drosophila

    Spotted wing Drosophila can be distinguished from other vinegar flies by spots on the wings of male flies, and by the ovipositor on female flies. First detected in the eastern United States in 2009-10, this small vinegar fly can lay eggs into grapes once the berries become soft after veraison. Unlike most vinegar flies, it can lay eggs into intact fruit, creating a risk of the white larvae (1-2 mm) being in berries at harvest time. With short generation time and high reproductive potential, populations can increase quickly, especially late in the season. Monitor for this fly using a vinegar-baited trap placed in the fruit zone and in the shade, checked weekly.

  • Thrips

    Feeding by thrips, particulary Frankliniella occidentalis, can cause scarring on fruit. During bloom, thrips feed on pollen and small berries. The symptoms become visible after the development of the berries and are characterized by brown, elongated corky scars, sometimes causing the berry to crack and the seed to prolapse.

  • Two-spotted spider mite

    This mite can cause severe damage to wine grapes if populations reach high densities. Thin-leaved varieties are most susceptible. These mites overwinter in leaf litter, develop on weeds in spring and move onto the vine as ground cover dries in summer. Water-stressed vines are most at risk.

  • Yellowjackets

    Yellowjackets and other wasps may break open grape berry skins during late summer. Early in the growing season, wasps are mainly predatory, but late in the season they begin to search for sugar, including ripened fruit.

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.