THE PHYLLOXERA.

Daily Telegraph (Napier), Issue 3005, 11 February 1881, Page 4

THE PHYLLOXERA.

Tho following is an accoufc of the habits of this insect, which has been the ».auso of so much mischief on the Continent of Europe. The insects are found both on the leaves and roots, and there is considerable difference in their appearanco in the two situations. The forms that appear on tho leaves have been for convenience termed gallicola, those on the roots radicicola. The gall or excresence produced by the insectis simply a fleshy swelling on the under side f [the leaf, more or less wrinkled and hairy, with a corresponding depression on the upper side, the margin of the crip being fuzzy, and drawn together so as to form a fimbriated mouth. Is is sometimes cup-shaped, but sometimes greatly elongated or purseshaped, and about tbe size of an ordinary pea. They are formed by the mother insect in spring, and her eggs are deposited in them. The young are speedily hatched, and scatter themselves over the vine, forming similar galls, and laying eggs as their parents did before. This process is continued for five or six generations during the summer, and in autumn the remaining insects descend to the roots, where they attach themselves singly or in groups, and thus hybernate. The radicicola, or rootinhabiting type, presents itself in two principal forms. The newly hatched larva; are nndistinguishable in all essential characters from those hatched in the galls, but in due time they shed the smooth larval skin, and acquire raised warts or tubercles, which at onco distinguish them from gallicola. In tho development from this point the two forms are easily seperablo The first or mother form never acquires wiugs, and is occupied during its lifetimo in laying eggs. The second or more oval form is destined to become winged ; after feeding a short timo they make their way to tho light, crawl over the ground and over the vines, and finally shed their last skin and assume their winged state. These are most abundant towards the autumn, and until the vines cease growing. The majority of them are females; tbey lay eggs that are botli male and female. The insects hybernate during the winter in the state of larva) and. a few eggs, and in spring commence to feed on the roots and deposit eggs as before The result which follow the puncture of the root insect is an abnormal swelling, the roots gradually dying and going to decay. During the first year of the attack there are scarcely any outward manifestations of disease, though the fibrous roots, if examined, will bo found covered with nodosities. The second year all these fibrous roots vanish, and the insects not only prevent the formation of new ones, bufc eventually cause the lsrger roots to become disorganised and rot. At this stage the outward symptons of the disease become manifest in a sickly yellowish appearance of the leaf, commencing at tho margin, and a, reduced growth of cane. In another year or two the vine is killed, and the insects have travelled through the soil and on the surface to the neighboring vines, or been wafted on the wind to distant vineyards.