Insetti dannosi per frutti . iiighly ingrandita, la breve linee o puntini a lato showingthe dimensione naturale. Durante il primo anno di presenza di insetti il outwardmanifestations della malattia sono molto lieve, sebbene thefibrous radici possono a questo punto essere coperto con il piccolo rigonfiamento-rali; ma, se l'attacco è grave, il secondo anno la leavesassume un malaticcio cast giallastro e il solito yearlygrowth vigorosa della canna è molto ridotto. Nel corso del tempo la vineusually muore; ma, prima che ciò avvenga, i pidocchi, avente littleor nessun tessuto sano per lavorare su, lasciare il vitigno morente e cercare

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Insects injurious to fruits . iiighly magnified, the short lines or dots at the side showingthe natural size. During the first year of the insects presence the outwardmanifestations of the disease are very slight, although thefibrous roots may at this time be covered with the little swell-ings; but, if the attack is severe, the second year the leavesassume a sickly yellowish cast, and the usual vigorous yearlygrowth of cane is much reduced. In course of time the vineusually dies; but, before this takes place, the lice, having littleor no healthy tissue to work on, leave the dying vine and seekfor food elsewhere, either wandering under ground amongthe interlacing roots of adjacent vines, or crawling over the 23G INSECTS INJURIOUS TO THE QRAPE. surface of tlie ground in search of more congenial quarters.During the winter many of them remain torpid, and at thatseason they assume a dull-brownish color, so like that of the Fig. 243.. roots to which they are attached that they are difficult todiscover. They have then the appearance shown at b in Fig.242. With the renewal of growth in the spring, the younglice cast their coats, rapidly increase in size, and appear asshown at e, /, g, in the figure ; soon they begin to deposit eggs ; ATTACKING THE ROOTS. 237 these eggs hatch, and tlie young ones shortly become egg-layingmothers like the first, and, like them, also remain wingless.After several generations of these egg-bearing lice have been})roduced, a number of individuals about tiie middle of sum-mer acquire wings. These also are all females, and theyissue from the ground, and, rising in the air, fly, or are carriedwith the wind, to neighboring vineyards, where they depositeggs on the under side of the leaves among their downyhairs, beneath the loosened bark of the branches and trunk, or in crevices of the ground about the base of the vineOccasionally individual root-lice abandon their undergroundhabits and form gal

Parole chiave associate all'immagine

• bookcentury1900
• bookdecade1900
• bookidin
• booksubjectinsectpests