The Yale expositor. (Yale, St. Clair County, Mich.) 1894-current, 1917-11-15
TIME IS RIPE FOR
TREATING ORCHARDS
Tree Diseases Can Be Dealt With
Now More Easily.
SHOULD HIT FIRE BLIGHT
Relatively Few Cankers Remaining
Can Be Cleaned Up Easily II
Effort Is Made.
BY DR.. G. II. cOONS,
Specialist in Plant Diseases, Michigan
Agricultural College.

Specialist in Plant Diseases, Michigan
Agricultural College.
East Lansing, Mich.-Michigan or
chardists, who for years have lost
much from the inroads of fire blight,
have an opportunity this fall to even
! the score. This disease of trees, fire.
quently present in such a degree as to
! almost discourage the most determined
! fruit grower, may be said now TO be
almost on its last legs" and few
well-delivered strokes, laid on without
1elay, should practically clean 1t up.
During the summer just ended, fire
blight has been of relatively small i'm
pOrtance in Michigan orchards,
though the causes underlying this I'M
usual absence of the disease where
before 1t has been so prevalent are not
easily seen. In spite of severe aphid
lnfestation but little blight has devel-
Oped. 1t seems probable, however,
that the dry weather in 1916 destroyed
the germs in their hold-Over locations.
1t can readily be appreciated, there
'ore, that If the few cankers still re-
naming are cut out at once the dis
,ase can be largely eradicated.
Fire blight, as is well known, lives
over the winter In so-called ''hold-over"
cankers. These can be found at the
base of withered, blackened and
blighted twigs. Locating of these dis
eased twigs is not difficult, for while
the healthy twigs shed their leaves
| off hn I'm,
their leaves. OF course, there are ex-
ceptions, but these can be recognized
upon examination.
In well-cared for orchards there may
not be more than half dozen cankers,
but at most 1t will not require more
than few days, work to go over the
orchard thoroughly and cut out all
these diseased areas.
1t is necessary TO do this because the
| fire blight germ remains alive over
the winter In these spots and furnishes
source of infection in the spring. If
these diseased centers are destroyed
the problem of handing the blight
during the following spring is much
simplified.
In cutting out the cankers, cut back
to sound wood and bark, and wipe off
every wound with 5 per cent carbolic
acid solution.
Black Knot Of Plum.
II must not be lost sight Of while
attention is being directed to fire blight
| that the fall is also a good time for
dealing with a number of other dis
eases of fruit trees. Black knot of
| plum is one of these. 1t is a disease
that has been known to horticulturists
| for years.
The control of this disease, If 1t is
taken In time, is comparatively easy.
though there is probably not COM
| munity in Michigan which does not
| contain some samples of the failure of
plum plantations from its ravages. The
habits of the black knot fungus are
such that the spores which cause new
Infection of twigs mature in the early
pring. Considering the delays apt TO
secure in all farm operations at this
| time. 1t seems very necessary that
| treatment of trees for black knot
should take place in the fall. When
the leaves have been shed from plum
and cherry trees all knots, even those
of very small size, must be carefully
cut out and removed from the orchard.
| If they are allowed TO fall to the
ground they will mature their spores
there Just as well as If they were left
on the trees.
Countless plum orchards have also
been gone over and only the large
black knots cut out. In such orchards
the disease has not been controlled,
for It Is necessary that the small knots
| as well as the big ones be removed.
The fungus does not extend vary far
In either direction from the knot,
hence 1t is only necessary to cut off a
very small amount Of wood with II.
In this case no disinfection need be
practiced. In making the cuts II is
best to follow the rules of good prun-
Ing, that is. leave no stubs. All large
wounds should be painted over with
white lead paint.
cankers.
II will be found also during pruning
operations in the winter that the fruit
grower must decide which Of two limbs
Is to be sawed from a tree. Before
making this decision he should look
over the limbs very carefully and note
whether any roughing of the bark oc-
ours. The cankered limbs should be