“This destroyer of the vine is known as the phylloxera, a name strange to our tongue, but losing nothing of its impressiveness in translation. ‘Phylloxera’ means ‘witherer of leaves.’ The plant-louse thus denominated does indeed cause the foliage of the vine to wither up—not acting on the leaves directly, [[285]]it is true, but attacking the roots. These, done to death by the insect’s sucker, cease to draw from the soil the nourishment needed by the vine. The vine-stock wastes away, and with it the leaves, which become yellow and withered.
Vine-pest (Phylloxera Vastatrix)
a, Healthy vine rootlet; b, rootlet showing nodosites; c, rootlet in decay; d, female pupa; e, winged female, or migrant. (Hair lines show natural sizes.)
“It is not merely the foliage, then, that the phylloxera dries up; it withers and kills the whole vine. Moreover, the name it bears was not invented expressly for it, but was borne by another before the ravager of vineyards became known. The louse that was first called phylloxera lived at the expense of the oak-tree and took up its station on the leaves, sucking the sap from them. There you have the true witherer of leaves. The vineyard louse has therefore [[286]]inherited an old appellation which fails to indicate fully the seriousness of the creature’s depredations.
“This last-named insect is a tiny yellowish louse, plump of body, but hardly discernible to untrained eyes, its length being barely three quarters of a millimeter. It lives in clusters on the minute ramifications of the roots wherever the bark is tender enough to enable it to push in its sucker. Its ranks are so dense that the infested rootlets wear a continuous coating of vermin which stains the fingers with yellow. It lays its eggs in little heaps in the interstices that occur in the swarming colony; and these eggs are oval in shape and sulphur-yellow at first, but turn brownish as the moment for hatching approaches.
“From these eggs there come, in a few days, new layers of eggs, which settle down beside the earlier comers and add their own progeny to the already overgrown family. Thus, as long as the season continues favorable, these myriad numbers of successive generations are added to the existing myriads, until the thread-like rootlets become completely hidden by the accumulated layers of eggs and the eggs themselves.
“Riddled with punctures, the rootlets swell up at intervals and present the appearance of a string of elongated seeds. Thus deformed, fatally injured in their delicate suckers, the roots cease to imbibe the nutritive juices of the soil, the famished vine languishes [[287]]for a time, putting forth only feeble shoots that are incapable of bearing fruit, and at last the whole plant dries up and dies. To secure its own prosperity the louse has killed its nurse.” [[288]]