Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1912-05-30
APPLE CANkER IN MAINE OR
CHARDS.
Its Cause and Control.

For number of years the Maine
agricultural Experiment Station has
been giving attention to the causes OF
disease in the bark of apple trees such
diseases cause a large amount OF loss
because the bark is frequently killed to
such an extent as to girdle the branches
and this leads to their death 50 that the
tree is finally destroyed.
Examination of branches affected by
eanker from different parts of the state
showed that a number of different fungi
were found associated with the disease.
These fungi have been studied in the
laboratory and NEGOTIATIONS have been
made with each of them in order to de-
termine the extent to which each is able
to cause disease.
As a result of these studies, 1t has been
found that at least three fungi found In
| Maine orchards are able to grow in the
| living bark of apple trees and cause dis
ease which may result in the death of
| the tree. Two other fungi have been
found which are very common on dis
| eased bark and small dead branches
but these have not grown to any extent
when placed in wounds in healthy apple
bark. IL seems that these two fungi are
| only able to grow on branches which
have become weakened in some way as
| in the case of trees which have not been
given proper care,
of the three fungi which spread rather
rapidly when placed in wounds ON
healthy branches. the one which is the
most important as cause of disease Is
the same fungus which causes the Leaf
SPOT of the apple and the black rot of
always enters the bark through wounds.
When the fungus has begun to grow
within the wound it spreads into the
healthy bark and kills it so that instead
of the wound healing over as it would do
if the fungus We're not present the area
of diseased bark becomes larger from
year to year. After a considerable area
of bark has been killed the fungus be-
gins to produce spores and thus the ma
terial is provided for the infection OF
new wounds in the bark as we'll as of
the leaves and fruit.
In order to prevent the spread of APP
pie eanker, it is necessary to remove
and burn all diseased wood which may
carry the spores of the fungi which
cause disease. Care should be taken to
make wounds in such a way that they
will heal readily and each wound should
be disinfected with a solution of copper
sulphate. one ounce TO one gallon OF
water and then painted over with white
lead in boiled linseed CT. Each wound
should be disinfected because the tools
which have been used in working on
| diseased branches are likely to carry
the fungus to healthy branches unless
| this precaution is taken
| While there are a number of fungi
| which cause canker the same methods
of control apply to all. In addition to
| the removal of the dead wood and bark
| which carry the spores of the fungi
| spraying should be practiced. The
| spraying which is done for the control
| of apple scab is of great Importance in
| the control of eanker This is due to the
| fact that the fungi which cause cankef
/ are producing large quantities of spores
at just the time when these applications
| are made and IL wounds are covered by
| the fungicide many infections will be
| prevented Spraying, however. cannot
| stop the growth of eankers which are
| already established These must be cut
| out and burned in order to destroy as
many of the spores as possible. In the
early stages. the diseased bark may be
| removed and the wound disinfected and
| painted over, but where n branch is
more than one-half girdled by the fun
gus it will usually prove to be best to
| remove the branch, cutting back 10
| healthy wood.
| CTIAS D. WOODS, Director.
Orono, Maine. May 90, 1872
Shop Men on a Farm.