Note #G-2

THE GRAPE PHYLLOXERA (Phylloxera vitifoliae) is native to the eastern United States and is one of the most important enemies of European grapes. It is of little importance on the grapes native to eastern North Carolina.

The biology of this plant louse is very complicated. One form of the insect feeds on foliage, where it causes unimportant gall-like growths. Other forms feed on the roots of the grape. These colonies do not injure the roots of domestic grapes, but are the cause of the damage done to the imported varieties. Injury to the roots is marked by the formation of galls followed by disintegration of tissue

THE GRAPE ROOT BORER (Vitacea polistiformis) is the larva of a clear-wing moth. The colors of the adults are dark bronzed-brown and yellowish orange, and the length of the body is about an inch. The larvae are an inch or more in length. The insect is found in the eastern states and in the Pacific Northwest. In North Carolina, this insect has been observed injuring bunch grape in the Rutherford-Cleveland County area to date. Damage to muscadine grapes is most likely present in every county in North Carolina.

Eggs are laid on foliage in late summer. One moth may lay as many as for hundred eggs (August and September). Eggs hatch promptly and the larvae drop to the soil and bore into the roots where they remain for almost two years. Such extensive injury to roots results in loss of vine vigor and production and eventual death. Pupation and emergence takes place in the summer of the second year. Pupation is in cocoons in the soil, outside the roots. Emergence of adult moth is characteristic in that its shed pupal skin partially protrudes through soil surface. It is at this time that close examination at base of vine can assure identification.

THE GRAPE SCALE (Aspidiotus uvae) closely resembles the San Jose scale in size and habits but usually differs in color. Grape scale is almost white, especially when they are found partly sheltered under loosened shreds of bark.

THE SAN JOSE SCALE (Quadraspidiotus perniciosus) may be found with the grape scale, and may be mistaken for the grape scale. San Jose Scale is dark gray in color and appears as round specks with a raised, nipple-shaped center. A reddish border nearly an eighth inch wide usually surrounds each scale.

THE GRAPE CANE GALL MAKER (Ampeloglypter sesostris) is a small reddish snout beetle about l/8 inch in length. It lays its eggs in the grape canes and the egg punctures, and subsequent feeding of the larvae in the tissues surrounding them results in the formation of characteristic gall-like swellings. The larvae feed in the pith of the canes, and become mature and transform to beetles by the end of the season. The beetles hibernate and lay their eggs the following spring and early summer.

THE GRAPE TOMATO GALL (Laseoptera vises). The small pinkish larvae of this midge cause a disfiguring swelling of new growth. It rarely occurs in large numbers.

THE GRAPE BLOSSOM MIDGE (Contarinia johnsoni) attacks the blossoms and buds and prevents the development of the fruits. It has been a commercial pest in the vineyards of western New York. The adults lay their eggs in the buds. The small, reddish maggots develop, do their damage, and drop to the ground to pupate in scarcely more than two weeks. They remain in the ground in an inactive condition until the following spring, when the brief period of activity recurs.

THE GRAPE ROOTWORM (Fidi viticida) is a chestnut-brown, slightly hairy beetle about 1/8 inch in length. The larvae feed on the small roots in the soil; adults do a considerable amount of damage to the plants by feeding on the foliage. The combined result is reduced vigor and lowered production of fruit. The pupae are formed in earthen cells in the soil near the crowns of the plants.

THE GRAPEVINE FLEABEETLE (Altica chalybea) appears in the spring when the foliage begins to unfold. They feed on the opening buds and on the unfolding leaves of the grape and may cause extensive injury.

After a period of feeding, the beetles lay their eggs on almost any part of the plants, including the leaves, but most often in the protection of a loosened strip of bark. Larvae feed in the open on the foliage along with the beetles which remain active for a considerable period. The larvae complete their development by mid-summer and drop to the ground, where they pupate at once. In the summa, the beetles emerge and enjoy a feeding period before they enter winter quarters in any available shelter.

Adult fleabeetles of this species are 1/5 inch in length and of a steely-blue or green color. Their jumping hind legs are more noticeably thickened than those of some other common fleabeetles. The larvae are brownish and are marked by the presence of black bristle-bearing tubercles.

LEAFHOPPERS - There is little important difference in the biology of the various species. They winter as adults, feed on other plants than grape before grape foliage becomes plentiful, and produce two or more broods, the adults enter hibernation when forced to do so by the lack of food and the occurrence of frosts. The injury by all forms is manifested by a spotting of the leaves, followed by yellowing or a rusty appearance, and finally by the death of the leaves, which may result, where the injury is severe.

The several grape leafhoppers are scarcely more than 1/8 inch in length. They are yellowish-green in color and the adults are variously marked with red or brownish patterns on the front wings.

THE GRAPE BERRY MOTH (Paralobesia viteana) is generally distributed east of the Rocky Mountains. It is the only common insect to damage, on a commercial scale, the berries of the grape. The grape curculio, which also feeds inside the fruit, is much less abundant and rarely a serious pest.

Larvae of the last generation of berry moth pupate in folds made in the leaf. The insect makes a semicircular cut and folds back the part detached, thus forming a shelter for a cocoon. Leaves detached and fall to the ground, where the winter is passed. Adult moths begin to emerge when the foliage of the grape has pretty well unfolded and continue emergence for several weeks. They lay eggs first on the blossom clusters and later on young grapes. Newly hatched larvae feed on the blossoms and small grapes, webbing clusters together and often destroying the entire cluster. In three to four weeks the larvae become full-grown and pupate. Second-generation moths emerge in ten to fourteen days and once more lay their eggs, this time on the berries. Second-brood larvae eat their way into the berries and feed on the pulp and the seeds.

The moth has a wing spread of little more than 1/2 inch and is brownish in color, with an irregular color pattern subject to some variation. The larvae are greenish or gray-green in color and may exceed 1/2 inch in length. Close examination shows that they are slightly hairy.

THE GRAPE CURCULIO (Craponius inaequalis) sometimes injures the berries, and its damage may be mistaken for that of the berry moth. The curculio has been reported from New England, Florida, Missouri, and intermediate points. The beetle is little more than 1/10 of an inch in length, and is blackish in color. They winter in sheltered situations and feed for a month or more in the spring before laying their eggs. Eggs are inserted into cavities formed under the skin of the grape berries, and the larvae develop inside the berries, feeding on the flesh and seeds. The footless condition of the larvae distinguishes them from the caterpillars of the berry moth. The larvae drop to the ground and pupate by mid-summer, and the adults emerge and enjoy a feeding period before hibernating.

THE GRAPE LEAF FOLDER (Desmia funeralis) caterpillars are light green with faint dark markings. They feed between folded portions of the leaves, but rarely become numerous enough to do more than give the vines a ragged appearance. They pupate in the folded leaves, and a second brood is formed in much of the range of the insect.

THE GRAPE LEAF SKELTONIZER (Harrisina Americana) is a small narrow-winged. moth of a smoky black color. Its larvae attract notice by their habit of feeding in groups, several worms being arranged, side by side, in a row which may extend well across a leaf. They consume the upper surface only. The insect is common on wild grapes and has been reported frequently in North Carolina.

THE ROSE CHAFER (Macrodactylus subspinosus) is usually included with the grapes; actually it is a general feeder, and it is somewhat misleading to call it a pest of any one crop. Apples, cherries, plums, roses, grapes, and many other woody plants suffer almost equally when the insect is abundant. The beetle is native to this country and occurs west to the Rocky Mountain region.

The body length of the beetles is just under 1/2 inch; the color is golden yellow with a lighter cast due to many white hairs. The larvae are small worms similar to white grubs and feed in the soil. The season of activity for the beetles is from the later part of May until early July, varying somewhat with the season and the locality. Abundance is extremely variable; in some years the beetle is scarce; in other years the trees, shrubs, and vines are loaded so that branches sag with the weight of the beetles, and destruction of foliage and fruit may be complete.

THE GRAPEVINE APHID (Aphis illinoisensis). The winter host of the species is Viburnum, and on plants of this group the winter eggs are laid. Migration to the grape takes place in the spring, either cultivated or wild varieties being attacked. Some damage is done to the foliage of the grapes, but more serious injury results from the infestation of the developing fruit clusters. In the fall (usually in October) the return migrants are produced and these in turn produce the egg-laying forms on the viburnums.

THE GREEN JUNE BEETLE (Cotinis nitida) THE JAPANESE BEETLE (Popillia japonica) . Injury is done by the adults which swarm into vineyards in mid-summer and attack foliage and fruit.

THE USE OF TRADE NAMES IN THIS INSECT NOTE DOES NOT CONSTITUTE ENDORSEMENT OF ONE PRODUCT TO THE EXCLUSION OF OTHERS.

Prepared by:
Dr. Kenneth A. Sorensen, Extension Entomologist
Revised: February 17th, 2005
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