AG Farmers’ Bulletin 1220. 
resistant vines for stock for vinifera sorts, and for some years new 
vineyard plantings have been of vines of this character. 
In the protection of vineyards on vinifera or other nonresistant 
roots, direct remedial measures are employed, as the use of fumigants, 
such as carbon disulphid, the flooding of vineyards for stated periods, 
etc. A very large amount of experimental work has been done in de- 
termining the best resistant stocks and best remedial measures for the 
phylloxera, especially in France. 
Wie, 51.—Phylloxera injury to vinifera vineyard in California. 
The life history of the phylloxera is quite complicated and. varies 
considerably, according to type of grape infested and the climate of 
the country inhabited by it. The phylloxera may be disseminated 
from nurseries on vines, or on vines from infested vineyards, and 
new centers of infestation come about principally in this way. In 
California spread from these centers is due to migration from in- 
fested vines over the soil, or through cracks in the soil of the small 
root-inhabiting nymphs or larve (fig. 53). These small larve may 
also be borne by wind and by picking boxes, and in hilly or irrigated 
vineyards perhaps some are carried by water. The winged form in 
