162 ; PLANT LICE. 
and unsatisfactory and not to be recommended except where other 
means are not available. 
“Submersion.—Next to the use of resistant stocks, by far 
the best means against the phylloxera is in inundating vineyards 
at certain seasons of the year and for definite periods, being ap- 
plicable wherever irrigation is practiced or water may be applied 
without too great expense. Submerging as a means against 
insects is a very ancient practice in southern Russia and Greece, 
but was first used against phylloxera in 1868 in France, and is 
now practiced wherever feasible. The best results are obtained 
in soils which water will penetrate rather slowly. In loose and 
sandy soils submersion is impracticable. For this treatment 
vineyards are commonly divided into rectangular plats by em- 
bankments of earth, the latter protected from erosion by planting 
to some forage crop. As now practiced, the vines are inundated 
shortly after the fruit is gathered, when growth of the vines 
has ceased, but the phylloxera is still in full activity and much 
more readily destroyed than during the dormant winter season. 
The earlier the application the shorter the period required. Dur- 
ing September from 8 to 15 days will suffice, and in October 
18 to 20 days, while if delayed until November a period of 40 
to 60 days will be needed. Copious irrigation at any time during 
the summer, if it can be continued for forty-eight hours, will 
give very considerable relief from phylloxera. 
“Planting in sand.—It was early observed that vines in very 
sandy soil were little subject to phylloxera injury, probably owing 
to the fact that the sand does not crack and allow the insects 
to escape and spread, being more thoroughly wetted with rains 
and subterranean moisture, and the insect is drowned out, as in 
submergence. The resistance is proportionate to the percentage 
of sand in the soil. In France vineyards are very successfully 
established on the sandy shores of the Mediterranean and in the 
alluvial sands of the valley of the Rhone and other streams. 
“American stocks.—The use of American vines, either direct 
for the production of fruit or as stocks on which to graft sus- 
ceptible European and American varieties, has practically sup- 
planted all other measures against phylloxera in most of the in- 
fested vineyards of the world. The immunity to root attack of 
American vines seems to be due to the thicker and denser bark 
