Mower County transcript., 1913-08-06
+ 4.
i. - g. ~
!: Fire: Blight Of Apple
: !. Trees.
BY e. C. STAkMAN, Assistant
Plant FathoIogisss. University
Farm, st. Paul.

=, Plant FathoIogisse. University
L Farm, St. Paul. :.
+ j. :. :. :. :. :. :. :. :. i.
There is great deal of twig and
branch tlig..1t CT arI:e trees this
year. Tie Elost stirling character
istics a1e tie Erown:c; cf ie.ves and
'hlacken;nc CT tw::cs. The dead leaves
do not fa1, but Remain cn the tree,
thus: ShcW.A; vcrJ c.early the posi-
"tion OF diseased branches. Upon close
.eE limitation the tlishted twigs or
h, ,alches :re seen to be very distinct
ly b!acke2ed.. Not only the sfaller
branches nay be Affected, but also
lar'~e! li-:1hs and, in some cases, even
the trunks.
Trees showing such symptoms as
these descE1EGd: sare usually affected
With fire light, so called because in
severe cases swhole trees may appear
to have been scorched The disease is
contagious. Usually the microbe is
carried to the tree by insects which
visit the flowers. When it is depos-
tied on flower it multiplies very
rapidly and the blossom is blackened
and killed, this phase of the disease
being known as blossom blight.
The infection may extend along under
the bark, killing and blackening the
twig, and often progressing into the
branches. 1t may also get into the
trunk, either through pruning wounds
or through shoots growing out from
the trunk. 1t may then cause the so
called body blight.
Infection takes place not only
through the flowers, but also through
tender shoots, water sprouts, suckers,
or spurs. For this reason, in orchards
where the blight has gained foot
hold, nothing should be done which
would encourage rapid growth. I'm
fortunately the same conditions which
are conducive to vigorous growth
of the tree are also conducive to the
rapid spread of the blight
The germs. are killed in many Of
the branches during the winter, but
in some they remain alive and be-
come active again in the spring.
These so called holdover cankers are
the source of new infection. Often on
such cankers drops of a milky liquid
are exuded and sometimes there is so
much exudate that it runs down the
trunk. The liquid contains countless
numbers of the bacteria, insects are
attracted to it and thus carry it to
other trees.
The only practicable method of
eradicating the blight from an or
chard is by cutting away all blight
ed wood.
This is most conveniently done in|
late summer or fall after the sea-
sons growth is over At this time thel
blighted portions are quite easily de-
tected. Every bit of blighted wood
should be cut out, even if it neces
states the sacrifice of the whole tree
The branches should always be taken
Off some distance back from the
clearly diseased parts in order to in
sure cutting out all the infected wood.
In the spring the orchard should be
carefully examined and eny limbs
which may have been missed in the
fall should be removed. During the
summer frequent inspections should
be made and the blight cut out when
ever it appears. Since the disease is
contagious the pruning knife should
be disinfected after every limb is cut.
Corrosive sublimate dissolved in wa
ter at the rate of one part to one
thousand parts of water is best for
this purpose. A cloth soaked in the
solution may be used to swab the
pruning instrument, or it may be
dipped directly into the solution.
The wild crabapple, thornapple,
Juneberry or service berry, and the
the same disease. These should, there
fore, be treated the same as apple
trees.
Cooperation is absolutely necessary.
Cutting the blight out of one orchard
when neighhcring one is still affect
ed will &c little good. Orchardists
should recognize the true nature of
the disease md make every effort to
exterminate it.
!. !. :. !. !. 4. !. =. :. =. :. = :. !. + !.
\ I.
!. The leach.lg manure heap i.
! on the farm fuIaichcs tie i
j. breeding plot for bcun nteoas 4
i. crop of flies ct the cCs., Of lew !.
4, .~.s-,4:o, -, ~, 4-<Ido ,,,,,,,. =, :,