29G PHYLLOXERA VASTATIUX, OR 
This is proved by the experience of French observers.. 
In vineyards where -the soil is of little depth, in' 
those where the drainage is deficient, and, particularly, 
in those French vineyards where, quantity rather than 
quality of wine being sought for, cultivation by the 
plough and frequent manuring are employed, the 
presence of the insect has been found to be more or 
less accompanied by damage to the vine; for in all 
these cases the fine root-fibres are near the surface 
and within reach of the insect. The same, of course, 
applies to newly planted vines, which are especially 
liable to destruction. 
On the other hand, Phylloxera vastatrix is never- 
observed to attack vines allowed to creep over pollarded 
trees, or over trellis work ; and vines so trained form 
probably nineteen-twentieths of all that are grown in 
North Portugal— the vines in such cases being usually 
well-established plants of many years growth, with 
deep reaching roots. Again, in the district in which 
port wine is produced, although the shape of the vine 
is bush-like, as in France, the roots descend to a great 
depth in the schistose soil—a depth, as I have myself 
had occasion to observe, sometimes exceeding fifteen 
feet. 
The same holds good, though to a less degree, with 
regard to the vines of the Bairrada district, and else- 
where in the province of Beira, where they are grown 
in bush-shape ; and it may be observed generally of 
this Consular district, that the wine cannot be profit- 
ably produced except in deep soils, on account of 
the frequency of long summer droughts, which cause 
the plant to send its roots far down in search of 
moisture. 
