PHYLLOXERA, or VINE-PEST, an American aphist (Phylloxera vastatrice), de structive to grapevines. It has four forms: sexual, leaf-gall, root and winged. sexual female lays an egg upon the vines during the autumn. About the time the buds open, the larva hatched from this egg forms a gall upon the tipper surface of a leaf and in about two weeks commences egg-laying, soon producing from 500=o 600 eggs within the gall it has made. The young which appear in about a week dis perse to other parts of the vine and form galls like the first. During the summer six or more generations are produced and the leaves may be completely covered with galls. The last brood produced before cold weather migrates to the roots where the insects hibernate until spring. During the growing season of the second year several generations of wingless females are produced upon the rootlets which swell more or less at the points of attack. In early autumn these root forms may produce winged females, which fly to the vines and lay eggs to continue the life-cycle. Often, however, no winged forms may be produced for several years, the root forms being capable of continued reproduction under favorable conditions. Flight is not the only means the insect has for dis tribution; it may be carried by vines trans planted from infested vineyards to new ones, by birds and insects to whose bodies the leaf form may cling; by winds which carry the leaf form either with leaves torn from the vines or otherwise; and through the crawling of the root form through cracks in the earth.
Though the insect is an American species, it has done little damage upon American varieties, since these are more resistant, probably because of the thicker bark of their roots and their robust habit of growth. But upon the Euro
pean varieties of Vitis vinifera the root-farm is especially troublesome. It was introduced into France upon American vines about 1859, and not only in France but throughout the grape-growing sections of Europe it quickly spread and did enormous damage. It is now known in nearly all grape-growing countries of the world. It is believed to be responsible for the failures of European varieties in America where, however it was unknown at first ex cept in the Rocicy Mountain region, and then, somewhat later, in California upon European vines. Since the root form, which is seldom seen, is the destructive form methods for com bating it were rarely satisfactory. The most frequently tried were probably bisulphide of carbon injected into the soil and flooding the ground. The one preventive remedy now prac tised is the grafting of the European varieties upon the roots of American varieties, especially those derived from Vitis labrusca, cestivalis, and V. riparia. Since this discovery was made, experiments have been made in the growing of European varieties in America, the vines having American roots, the object being to discover the cause of previous failure of the European varieties. Consult Marlatt, (Princi pal Insect Enemies of the Grape> (United States Department of Agriculture, Farmers' Bulletin, No. 70; Washington 1898). See GRAPE INSECT-PESTS.