CULTIVATION OF THE GRAPE UNDER GLASS. 157


Mitpew of the vine has been a serious source of loss and dis-
appointment. Strictly it is nota disease, but a parasitic, fungoid
plant, which, under certain favoring’ conditions grows upon and
derives its sustenance from the tissues of the vine. By its growth
the further growth of the vine is arrested, and if sufficiently
abundant the crop of fruit is lost, and the vine itself seriously
and sometimes fatally injured. It is most likely to make its ap-
pearance in hot, dry weather, particularly if a draught of air be
allowed through the house. By keeping the top ventilators open,
and not suffering any draughts, the mildew may be wholly pre-
vented. Little injury need be apprehended from it after the
Grapes are once well colored.
There sometimes forms on the lower surface of the leaves a
collection of little green warts. They are caused by a close,
warm atmosphere, saturated with moisture, and can be prevented
by maintaining a free circulation of air, moderately charged with
moisture.
AiR-RooTs on the vine are caused either by the atmosphere
of the house being kept too moist, or because the border is too
cold, or by both these causes acting together. When the natural
roots are in a border that in texture, temperature and moisture
is congenial to their growth, and the atmosphere of the vinery
what it ought to be, there will be few air-roots.
Asarule, one pound of grapes to every two superficial feet
of glass is a fair crop, yet a sound discretion must bé exercised
in the amount of crop, which should be proportioned to the vigor
of the vines.
SELECTION OF VINES.
