Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1914-09-23

Experiment Station from about the
middle of July to the middle of August
concerned the work of the leaf blister
mite on the apple. For the most part
| this work was not unnaturally mis-
taken by the people collecting it for
some fungus disease, as the blotches
on the leaves resemble somewhat the
injury caused by leaf-spot fungi. The
mites themselves are so small that
they are invisible to the unaided eye,
and although they can be seen as
moving specks with a good hand lens
| it takes microscope to give any real
idea of their appearance
They are not insects in the true
sense, of that term, but belong to the
same class of animals as the spiders.
They are whitish, elongate little Great
ures about LBS inch in length and
! live within the tissue of the leaf, de-
veloping their colonies there within
| the blister or gall which the irrita-
ton of their presence causes. In win
ter they seek the protection of the
scales in the leaf buds.
They are, indeed, among the smallest
animal forms which attack cur crops,
but they frequently occur in such
abundant colonies that the damage
they do to the leaf is very conspieu-
Gus. This injury may first be noticed
in spring when it appears as reddish
or yellowish green raised spots or
blisters on the leaves; but it is not
until much in the season that it at
tracts general attention, and by this
time the blister spots are brown, CIV
| ing the leaves a diseased appearance.
| If the attack is severe the foliage is
likely to fall prematurely and drop
| ping of the fruit sometimes results.
There is no remedial measure apph-
cable at the time of the year when the
damage is apparent and by winter the
work as we'll as the mite being out
of sight, the trouble is likely also to
be out of the mind of the orchardist.
The leaf blister mite, however, yields
readily to treatment either by miscible
oils and homemade oil emulsions or
lime sulphur. Trees sprayed with
lime-sulphur for other purposes do
not need especial treatment for the
blister mite. When this remedy is
applied for the blister mite alone
dilution of one part to ten Of water is
sufficient when the concentrated solu-
ton tests 81 degrees Beaume. This in
secticide may be applied either in the
fall after the leaves have fallen or in
the spring any time before growth
starts. The reason that a dormant
spray is effective Is that the adult
mites hibernate under the bud scales,
and thorough spray, which should
coat the tree completely will kill
them, thus preventing their injury the
fol
in, numbers, the mites do not ordinar-
lily gain ground rapidly and control
measures are not required every year.
The orchardist himself can Judge as to
when the damage is severe enough to
make treatment advisable, if care is
taken to ascertain whether the leaf
injury is due to mites, leafspot fungi
or spray injury.
Spraying for the leaf blister mite
has passed the experimental stage and
the satisfactory results of this treat
ment have.ebeen demonstrated many
times in large commercial orchards.
Judging from the appreciative letters
/ of thanks received by this Station
/ from people who used lime-sulphur at
/ our recommendation, this spray evil
IDENTIFY is as efficient under Maine con-
ditions as elsewhere. The leaf blister
mite is widely spread and seriously
abundant here and any earnest or
chardist who has had a heavy infes-
| tation of this pest during the summer
| just past would do we'll to give it the
attention of a thorough spray as a
part of his fall or early spring calen-
dar as an assurance of better condi-
lions next year.