PHYL'LOXE'RA (Neo-Lat. nom. pl., from (1k. oiRtNoc, phyllcm, leaf £np6s, a'f'ros, dry).
Au bisect I if Mer Van (nig ( PhYllthreni his I. which belongs to the aphid family. and accidentally introduced into France about 1ti5!1 upon Anwriean viol's, spread through the principal vine districts of Southern Europe, enormous damage. It has furtiogr spread into Algeria and through Southern Russia into the :adjoining countries of Asia. It has also been parried into New Zealand and South Africa. as well as portion- of Australia. In the United States it was at first known only in the region of the Itoeky Mountains, hul was afterwards found in California. where it is confined to those vineyards in which the European vine is grown from its own roots.
The Phylloxera is indigenous to North Amer bat, where it has always existed on the wild vines. It occurs in four forms, the leaf-gall form (gal the root form (radieicola), the winged or colonizing form, and the sexual form. The sexual insert lays the winter egg on the old wood. The young one hatching in the spring proceeds to a young leaf and Mentes itself upon the upper surfaces, gradually forming a gall about itself which projects from the lower side of the leaf. It reaches full growth in fifteen days. and fills its gall with small yellow eggs, from :MO to 1100 in number. These eggs hatch in eight days, and the young migrate to all parts of the v lute to form new galls. Six or seven gen erations of these wingless females follow one an other through the summer, frequently covering the leaves with galls. At the approach of cold weather young proceed to the roots, remain ing dormant until spring. In the spring the loot is attacked by a series of general' s of females which produce swellings upon the rootlets. During the late summer and fall some of the root-lice give birth to winged females, whiell escape through the soil and Ily to neigh boring vines, laying their eggs on the Vrom these egg., the sexual generation issues, and the life eycle is begun again. The root form, how ever, may proceed in successive broods for a nfimber of years, as is the ease with the Euro pean vines on which the leaf form rarely occurs.
The insect is spread Ly the flight of the winged females. by the migration of the rootliee through cracks in the soil, and by the carrying of the leaf-gall lire by winds, by birds, and by other insects, and further by the shipping of infested rooted plants or cuttings bearing the winter eggs. The leaf form is especially noticeable upon Amer ica' vines, and is common upon the wild vines. The root form is rarely seen, but is the cause of the only severe injury to the plant. When oecurring plentifully, the death of the vine in a few years is certain. The root-lice first produce enlargements on the rootlets, their work to the larger roots. These become swollen and broken and finally die and rot. The vine stops growing. the leaves become sickly and yel lowish, and since the Phylloxera disappears from the dead roots, the cause of the death of the plant is frequently obscure. The European vine (ritis einifera) is particularly subject to the attacks of the root form, while most Amer ican vines, although frequently carrying the leaf galls, are more or less immune to root attacks.
The remedies used for this pest are the sub terranean injection of bisulphide of carbon, and the submersion of the roots by inundating vine yards at certain seasons of the year by water. The standard preventive now employed all over the world is the use of American' vines as stocks upon which to graft the susceptible European varieties. The immunity of the American vines seenis to he due to the thicker bark covering of the roots, and to a greater natural vigor. 'rite chief resistant varieties of American vines are the ,'Estivalis, the lliparia, and the Labrusca. Some American vines, however, as the Delaware, are almost as susceptible as the European vines. The varieties of the .Estivalis most used are the Herhemont and Cunningham; of the Riparia, the Clinton, Taylor, and Solonis. Consult Narlatt, Prinripal Imsect Enemies of the Grape (Wash ington, 1898).