. Animal biology. Biology; Zoology; Physiology. BIOLOGY AND HUMAN WELFARE 411 has spread all over the United States. The adult female insect lies permanently attached by its beak to the bark, underneath a tiny waxy scale which it secretes. Here eyes, legs, and antennae are lost and the sac-like creature sucks the plant sap and repro- duces. It is estimated that the progeny of a single individual during one season would number thirty million if all were to sur- vive. (Fig. 264.) About forty years ago the vineyards of France, and later those of California, appeared to be doomed to destruction by
. Animal biology. Biology; Zoology; Physiology. BIOLOGY AND HUMAN WELFARE 411 has spread all over the United States. The adult female insect lies permanently attached by its beak to the bark, underneath a tiny waxy scale which it secretes. Here eyes, legs, and antennae are lost and the sac-like creature sucks the plant sap and repro- duces. It is estimated that the progeny of a single individual during one season would number thirty million if all were to sur- vive. (Fig. 264.) About forty years ago the vineyards of France, and later those of California, appeared to be doomed to destruction by the attacks of a species of minute plant lice, or Aphids. The French govern- ment offered a large reward for an effective remedy, and many entomologists and botanists devoted all their time to the study of the problem. Eventually it was discovered that certain Ameri- can wild Grapes were naturally immune to the pest. Accordingly by grafting the cultivated grape upon the resistant wild stock a combination was effected which saved the vineyards of both coun- tries. (Figs. 222, 265.) The Mediterranean Fruit Fly appeared a few years ago in certain Florida orchards but the invasion apparently has been repulsed by the vigilance of the United States Bureau of Ento- mology and Plant Quarantine. It is the larvae of the fly that are the mischief-makers, because when they develop from eggs de- posited in the fruit they soon ren- der it unfit for human food. When we realize that the annual fruit and vegetable crop of Florida amounts to well over a hundred million dollars, it is no wonder that this fly is one of our most notorious foreign emigrants. But Fig. 261. — Mediterranean Fruit we maintain a defense on the Rio £Iy, keratitis capitata. (From U. S. „ , . __ . Department oi Agriculture.) Grande against the Mexican t ruit Fly, and others throughout the country against our many native species of Fruit Flies, though the latter are held in check to a considerable extent by their own i
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