The vines should be sprayed with paris green, one pound to fifty gallons of water, just before the buds begin to swell or with some other arsenite. Much pains should be taken to make this application thorough. Later when the worms appear on the leaves, paris green may be applied at the usual strength, one pound to 150 gallons of lime and water, or combined with bordeaux mixture. Both upper and under surfaces of the leaves should be covered. Applications of arsenicals for the grape-vine fidia will help greatly to keep this insect in check.
[103] Grape leaf-hopper (Typhlocyba comes Say).—There are several species of leaf-hoppers which attack the grape but this species is probably the most common in this State. These little leaf-hoppers are often erroneously called thrips. The adult insects measure about one-eighth of an inch in length. They vary greatly in color but the prevailing color is usually light yellowish-green. The back and wings are ornamented with bright red, yellow and brown. They are found upon the vines from spring until fall. They feed together, sucking the sap from the leaves, principally from the under surface, causing them to turn brown in patches. The eggs are deposited singly in the tissue of the under surface of the leaves. The young resemble the adults in form but are not provided with wings and are green or yellowish-green in color. There are several broods during the season. Some of the adults of the last brood hibernate in any convenient rubbish about the vineyard. Treatment for young hoppers should be made early in July. To obtain the best results use whale-oil soap at the rate of one pound to ten gallons of water, directing the spraying with the hand. Vineyards and adjacent land should be kept as free as possible from grass and weeds as they afford shelter to the insect.
[104] Grape berry moth (Polychrosis viteana Clem.).—The young caterpillars feed within the grapes finally causing them to turn dark colored and to wither. This injury is sometimes mistaken for the black-rot. After devouring the soft parts of one grape the caterpillar goes to another, fastening the two together by a silken thread. This may be continued until several in a bunch have been destroyed by one caterpillar. The young caterpillars are very light green in color with a brown head. When full grown they measure about one-fourth of an inch in length and are dark olive green in color tinged slightly with red. The cocoon is formed on a leaf and is partially composed of two small pieces cut out of the leaf. The adults of the spring brood emerge in from twelve to fourteen days. The fore-wings have a bluish tinge and are marked with brown, while the posterior wings are dull brown. The moths are small measuring nearly half an inch from tip to tip when the wings are spread. The eggs are probably laid late in June or early in July. There are two broods annually in this State. As the caterpillars spend most of their lives within the grape berries, spraying does not entirely control the pest. Yet the arsenicals applied for the grape-vine fidia will help much in keeping it in check. Picking and destroying the infested fruit and the leaves containing the cocoons helps much.
[105] For a full account of the geology of these lakes and the valleys in which they lie, see the Physical Geography of New York State by Ralph S. Tarr. New York. 1902.
[106] Black-rot (Guignardia bidwellii (Ell.) V. & R.) usually appears first on the leaves where it forms circular, reddish-brown spots on which black pimples, or spore cases, develop. Within these spore cases, at maturity, are the summer spores. These are distributed by the elements to the growing parts of the plant and form new centers of infection. The diseased berries show analogous circular spots bearing spores and as the disease progresses the grapes wither, turn black, and become hard and shrivelled, sometimes clinging to the vine until the following spring. Growing shoots are attacked as well as leaves and fruit. During the winter and spring the resting spores are formed, usually upon the shrivelled berries.
Treatment consists of destroying as far as possible all diseased fruit, old leaves and prunings and in spraying thoroughly with bordeaux mixture as follows:—
1. Just as the pink tips of the first leaves appear.
2. From ten days to two weeks after the first spraying.
3. Just after the blossoming.
4. From ten to fourteen days after the third spraying.