. Principles of economic zoo?logy. Zoology, Economic. 146 BRANCH ARTHROPODA curiously enough, says Kellogg, "came to California—in which state it has done much more damage than elsewhere in our country—from France, in- troduced upon imported cuttings or roots " (Fig. 115). Probably not less than 30,000 acres of vineyards have been destroyed by it since it was first noticed in 1874. "The Phylloxera appears in four forms: (1) the gall form, living in little galls on the leaves (Fig. 114), and capable of very rapid multiplication (this form rarely appears in California); (2) the ro
. Principles of economic zoo?logy. Zoology, Economic. 146 BRANCH ARTHROPODA curiously enough, says Kellogg, "came to California—in which state it has done much more damage than elsewhere in our country—from France, in- troduced upon imported cuttings or roots " (Fig. 115). Probably not less than 30,000 acres of vineyards have been destroyed by it since it was first noticed in 1874. "The Phylloxera appears in four forms: (1) the gall form, living in little galls on the leaves (Fig. 114), and capable of very rapid multiplication (this form rarely appears in California); (2) the root form (Fig. 115), which is derived from individuals which migrate from the leaves to t he roots, and which by the piercing of the roots, sucking the sap, and producing little quickly decaying tubercles on the rootlets, does the serious injury; (3) the winged form (Fig. 116), which flies to new vines and vineyards and starts new colonies; and, finally, (4) the sexual forms, 3:::fe^^w2 w. Fig. 116.—Phijlloxi'ra vasta'lrir: a, Migrating stage, winged adult; 6, pupa of same; c, mouth parts with thread-like sucking seta" removed from sheath; d and e, eggs showing characteristic sculpturing; all enlarged (Mariatt.) male and female (Fig. 117), which are the regenerating individuals, ap- pearing after several agamic general ions have been ; The gall stage may be omitted, and the indi\iduals hatched from the fertilized eggs go directly to the roots. The gall form can be prevented by spraying to kill the winter eggs. But about the only real cure for the infested roots is to dig them up and burn them and plant out resistant vines. The wild vines of the Mississippi Valley have (>\'iil\'(>d with the Phylloxera, and are capable of living and growing in spite of the pests. The French vine- yards, as well as those of California, ar(> being renewed by grafting French stocks upon the resistant roots, thus rendering the vines practically im- mune. There are man
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