ry, there is never an intermission in the warfare
against these pests.

Mealy-bug is usually a sign of sloth on the part of the gardener. In
a grapery devoted exclusively to grape-growing, it should never be
seen, but, since gardeners must often grow other plants in the
grapery, mealy-bug sooner or later appears and is often hard to
dislodge. It is best repelled by removing the loose bark on the trunks
which harbor the pest and then washing with kerosene emulsion. When
this becomes necessary, not only the vines but the rafters and all
parts of the house should be sprayed with the emulsion.

Red-spider is another pest usually found in the grapery, but it
thrives only in a dry atmosphere and is easily gotten rid of by
syringing. As soon as red-spider appears in a house its appearance is
usually known by the reddish tinge on the foliage; syringing should be
kept up until the pest is disposed of, keeping the house damp in all
except dull weather. Syringing is done only when plenty of air can be
given and when it can be followed by sunlight so that the water
remains on the vines as short a time as possible.

Thrips, another small insect, is sometimes troublesome but not often
and is now easily controlled by applications of nicotine. Much care
must be taken in the application of nicotine late in the season,
otherwise the fruit will be injured.

The only fungous disease of the grape troublesome in the greenhouse is
mildew. Mildew is usually brought on by a sudden change of temperature
or by draughts in the grapery. Gardeners are of the opinion that east
winds, in particular, give unfavorable conditions for mildew and
prefer to open the ventilators to the west. If taken in time, mildew
is easily kept in check by preventing the conditions which favor it,
and by dusting the vines in dry sunshine with sulfur.

[Illustration: PLATE XVI.--Elvira (x2/3).]

CHAPTER XII

GRAPE PESTS AND THEIR CONTROL

In common with other cultivated fruits, grapes are at the mercy of
numerous insect and fungous pests unless man intervenes with remedial
or preventive treatment. Happily for viticulture, knowledge of the
pests of the vine has made such advancement in recent years that
practically all are now controlled by remedial or preventive measures.
Possibly no field of agriculture has had greater need, or received
greater aid from science in the study and control of insects and
diseases than grape-growing. A separate treatise would