Grape-slug or Saw-fly (Selandria vitis). — Larva about one-half inch long, yellowish green with black points, feeding upon the leaves ; two broods.
Remedies. — Arsenicals. Hellebore.
Grape Root-worm (Fidia viticida). — The small white grubs feed upon the roots, often killing the vines in a few years. The adults are small grayish-brown beetles that eat peculiar chain-like holes in the leaves during July and August. Cultivate thoroughly in June, especially close around the vines to kill the pupae in the soil. At the first appearance of the beetles spray the plants with arsenate of lead at the rate of 8 or 10 pounds to 100 gallons of water, to which should be added 1 gallon of molasses (Geneva Experiment Station).
Grape-vine Flea-beetle (Graptodera chalybea). — Beetle, of a blue metallic color, about one-fourth inch long, feeding upon the buds and tender shoots in early spring.
Treatment. — Arsenicals to kill the grubs on leaves during May and June. The beetle can be caught by jarring on bright days. Grape-vine Root-borer (Memythrus polistiformis). — Larva, one and one-half inch or less long, working in the roots.
Preventive. — Thorough cultivation during June and July. Treatment. — Dig out the borers. Grape-vine Sphinx (Ampelophaga myron).— A large larva, two inches long when mature, green with yellow spots and stripes, bearing a horn at the posterior extremity, feeding upon the leaves, and nipping off the young clusters of grapes ; two broods. Treatment. — Hand-picking. Arsenicals early in the season. There are other large sphinx caterpillars which feed upon the foliage of the vine and which are readily kept in check by hand-picking and spraying. Phylloxera (Phylloxera vastatrix). — A minute insect preying upon the roots, and in one form causing galls upon the leaves.
Preventive. — As a rule this insect is not destructive to American species of vines. Grafting upon resistant stocks is the most reliable method of dealing with the insect yet known. This precaution is taken to a large extent in European countries, as the European vine is particularly subject to attack.
Remedies. — There is no reliable and widely practicable remedy known. Burn affected leaves. Bisulphide of carbon poured in holes in the ground, which are quickly filled, is very effective. Carbolic acid and water used in the same way is also recommended. Flood the vineyard. Snowy Cricket. — See under Raspberry, p. 331. Leaf-hopper (Typhlocyba comes). — These small yellowish leaf-hoppers, erroneously called " thrips," suck the sap from the underside of the leaves, causing them to turn brown and dry up.
Treatment. — Spray the under side of the leaves very thoroughly with whale-oil soap, 1 pound in 10 gallons of water, or with " Black-leaf" tobacco extract, 1 gallon to 100 gallons of water; or 1 gallon " Black-leaf 40 " in 1000 gallons of water about July 1, to kill the young leaf-hoppers. When using tobacco extract add about 2 pounds whale-oil soap to each 50 gallons to make it spread and stick better. Repeat the application in a week or ten days. In houses, tobacco-smoke, pyrethrum poured upon coals held under the vines, syringing with tobacco-water or soap suds. Grasshoppers. — See under Corn, p. 314.
Rose-chafer (Macrodactylus subspinosus). — The ungainly, long-legged, grayish beetles occur in sandy regions, and often swarm into vineyards and destroy the blossoms and foliage.
Treatment. — At the first appearance of the beetles spray with arsenate of lead at the rate of 8 or 10 pounds to 100 gallons of water, to which should be added 1 gallon of molasses.