s must be closely watched and if the lice
appear in any considerable number they must be promptly attended to or
serious damage is likely to result.

These are by no means all the insect pests which the fruit grower has
to combat, but they are usually the most important. Canker worm and
tent caterpillars often do great damage in unsprayed orchards, but
they are easily controlled by an application of a poison as soon as
they appear. The same is true of other caterpillars and leaf eating
worms. Apple tree borers are frequently serious, especially in young
orchards, where the trees should be regularly "grubbed" and the borers
dug out or killed with a piece of wire. They may be prevented to some
extent by painting the tree trunks with a heavy lime and sulphur or
some gas tar preparation.

DISEASES.--Although not as numerous as insects, the diseases which
attack the apple inflict great damage and are fully as difficult to
control. They are caused by bacteria and by fungi which may be
compared to weeds growing on or in the tree instead of the soil. If
either of these works within the plant, as is sometimes the case, it
must be attacked before it enters. It is very necessary to be thorough
in order to control these diseases. Weather conditions influence
nearly all of them materially. Of those which attack the apple tree or
fruit we have selected three as the most serious and the most
necessary for the grower to combat, namely, (1) apple scab, (2) New
York apple tree canker, and (3) fire blight. To these should be added
in the South and middle latitudes, sooty blotch and bitter rot.
Baldwin spot is also frequently serious in some seasons and
localities.

(1) THE APPLE SCAB, commonly known among growers as "the fungus," is
the most important of our common apple diseases and is most evident on
the fruit, although it attacks the leaves as well. In some seasons the
fruit is made almost unsalable. This disease lives through the winter
on old leaves. In the spring about blossoming time the spores are
scattered by the wind and other agencies, and reaching the tender
shoots germinate and enter the tissues of the plant. Their development
is greatly dependent on the weather. In a season in which there is
little fog or continued damp or humid weather, they may not develop at
all, but where these conditions are present they frequently become
very virulent.

Spraying will be governed by the weather conditions, but the mixture
must be