Insects injurious to fruits . empty, while those on the younger ones are swarming withoccupants. These galls are very common on the Clinton grape and othervarieties of the same type, and are also found to a greater orless extent on most other cultivated sorts. They sometimesoccur in such abundance as to cause the leaves to turn brownand drop to the ground ; and instances are recorded wherevines have been defoliated from this cause. The numberof eggs in a single gall will vary from fifty to four or fivehundred, according to its size. There are several genera-tions of the lice during the season,
Insects injurious to fruits . empty, while those on the younger ones are swarming withoccupants. These galls are very common on the Clinton grape and othervarieties of the same type, and are also found to a greater orless extent on most other cultivated sorts. They sometimesoccur in such abundance as to cause the leaves to turn brownand drop to the ground ; and instances are recorded wherevines have been defoliated from this cause. The numberof eggs in a single gall will vary from fifty to four or fivehundred, according to its size. There are several genera-tions of the lice during the season, and they continue toextend the sphere of their operations throughout the greaterpart of the summer. Late in the season, as the leaves become -2M INSECTS INJURIOUS TO THE GRAPE. less succulent, the lice seek other quarters, and many of tlieinfind their way to the roots of the vines and establish them-selves on the smaller rootlets. By the end of September thegalls are usually deserted. In Fig. 241 we have this type FiQ. of the insect illustrated : a shows a front view of the younglouse, and h a back view of the same, c the egg, d a sectionof one of the galls, e a swollen tendril,/, (/, h, mature egg-bearing gall-lice, lateral, dorsal, and ventral views, i anteimse,and j the two-jointed tarsus. When on the roots, the lice subsist also by suction, and theirpunctures result in abnormal swellings on the young rootlets,as shown at a in Fig. 242. These eventually decay, and thisdecay is not confined to the swollen portions, but involves theadjacent tissue, and thus the insects are induced to betakethemselves to fresh portions of the living roots, until at lastthe larger ones become involved, and they, too, literally wasteaway. In Fig. 242 we have the root-inhabiting type, Radicioola,illustrated: a, roots of Clinton vine, showing swellings; 6,yoinig louse, as it appears when hibernating ; c, d, antennaeand leg of same; e, /, g, represent the more mature lice. ATTACKING THE ROOTS
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Keywords: ., bookauthorsaunderswilliam183619, bookcentury1800, bookdecade1880
