84 INSECTS AND MAN 



the pest was accidentally conveyed to France on some rooted 

 vines, and commenced activities in its new home at two 

 points, near Bordeaux and near Gard. Unfortunately, the 

 nature of the mysterious failure of the vines was not under- 

 stood for some years, with the result that the insect spread 

 rapidly in all directions, and, by 1884, nearly two million 

 five hundred thousand acres, or more than one-third of the 

 French vineyards, had been totally destroyed, and all the 

 others were more or less affected. In many places the 

 vines, which had once yielded so rich a harvest, being 

 reduced to stumps, were used for firewood. 



Measures taken to eradicate the pest have not proved very 

 effectual, so that, to-day, there is no vine-growing district 

 of any importance in Southern Europe that is exempt from 

 Phylloxera ; furthermore, it has spread through South 

 Russia to the adjoining countries in Asia, to Algeria, South 

 Africa, and New Zealand. About 1874 it was introduced 

 into California, on vines imported from France, where it 

 wasted little time in destroying thirty thousand acres of 

 vineyards. Here we come to a very interesting and im- 

 portant point with regard to this insect its behaviour and 

 mode of life differs according to whether its food plant is 

 the American or European vine. Phylloxera exists in four 

 forms ; one of these forms is found upon the leaves, another 

 on the roots. The leaf form, though causing considerable 

 disfigurement to the plant, is not of great importance in 

 itself; but the root form, working unseen, is the really 

 harmful stage, rendered the more so because its presence 

 may never be detected till the plant is killed; in fact, 

 during the first year, the vine may be apparently benefited, 

 as we shall see later. For some unexplained reason, the 

 leaf form is found, for the most part, on American vines, 

 and the root form on European ones a fact which amply 

 explains how an unconsidered insect, in its native home, 

 became a great pest in Europe. 



The life-history of this dreaded vine pest is exceedingly 



