228 PESTS OF ORCHARD AND SMALL FRUITS 
same species of lice cause swellings which later decay, resulting in the 
death of the roots. The serious injury is that done by the root-in- 
habiting forms. 
On native grapes, in the eastern states, this 
insect is fairly common, but the roots of these 
grapes are resistant and no notable damage 
results. On imported grapes in the Pacific 
coast states the roots are attacked rather than 
the leaves, and here the insect is serious, its 
work resulting in the death of the vines. The 
lice are small, yellowish, and soft bodied. 
Winged generations are produced, which spread 
the species to new fields. 
Fic. 285. — Work of the 
Grape-phylloxera on 
roots. Original. 
Fic. 286.— Galls on grape leaf caused by the - 
Grape-phylloxera. Original. 
In control, in California, imported varieties are grafted on native 
eastern stocks, thus securing practical immunity. Infested vineyards 
are treated by flooding, applying water first for 10 days, just after the 
picking season, again for a similar period a few weeks later, and for a 
thirty-day period in winter. Vines grown in nearly pure sand are not 
severely attacked. 
