American Fork citizen. [volume] (American Fork, Utah) 1912-1979, 1915-04-10
Fire Blight or Pear Blight
CBy Luther Giddings)


The fire blight or pear blight as II
Is often called has become very preva-
lent in this vicinity during the past
year or two, and unless something Is
done to check II. pear growing may
| become thing of the past. In many
communities throughout the United
States people have been forced to dis
continue raising this fruit on account
of this disease. and for that reason 1t
Is up to the fruit growers of this val
ley to take steps before IL is too late.
This disease is caused by form OF
bacteria, some what similar TO those
which cause so much disease among
| the human race. II Is found In two
forms. twig blight and canker blight,
and although they seem to have very
little resemblance to each other, they
are merely different forms of the same
thing. The twig blight on the pear
has an appearance of fire damage,
that is, the limb and leaves become
dark and dead as though they had
been scorched. The apple Is also af-
fected considerably In this commune
| ty, but the twigs In this case do not
have as much of the scorched appear
ance as the pear. Twig blight In
either case, starts at the tender end
of the twls, or still more frequently,
at the fruit spur and grows very rap
idly down the branch, sometimes pro-
crossing several inches per day AS
the wood becomes hard In the sum
mer. the progress of the disease Is
checked and there is a well marked
line between the healthy aud diseased
tissue. In every case Il viii be-found
that the disease is confined 10 the
bark and inner bark OF the branch
and that the wood Is not affected only
as much as is caused by the bark dy-
ing
Canker blight shows itself as dark
colored diseased condition Of the-bark
OF the tree, sometimes In only small
patches, sometimes In larger bodies
that completely girdle the tree or
branch on which they are found. II
does not occur on the smaller twigs
but on the larger branches or on the
main trunk of the tree. II Is usually
quite hard and even impossible to tell
Just where the disease stops and the
healthy wood begins, wherin II differs
from the twig blight The bark and
inner bark Is dead, but the wood is
unaffected. or at least not discolored
In one orchard, which the writer in
spected In this town. out of forty
promising young pear trees, there
we're only two that were not infested
with one or both forms of blight.
| The blight Is spread to new l0ca-
tons In the summer or spring by in
sects who visit the cankers for the
sticky juice which appears with the
growing season From here Il is
spread to growing shoots and to the
blowers to start new twig blight. Some
times II Is carried to wounds In the
bark and new cankers are formed
Pear blight is seldom or never spread
from the twig blight, as the disease
cannot live over winter In the twigs
but must stay In the larger branches
To cure blight, is only to prevent
Its spreading. No spray has even been
discovered which does any good, al
though many are advertised for this
purpose The only remedy is to prune
out every case OF canker blight which
can be found. This Is Necessary d.
tcause here IL where the bfrN - -
lover. In the spring II is p<cessafy ft6
Icut out a considerably larger area
than is shown to be- diseased. Some
times II may be necessary TO cut down
whole trees. All these prunings
|
spread from them The knife or
pruning shears must also be CAREFUL
ly dislnfected after each cut Is made
or they may spread the blight all over
the orchard. To disinfect them wash
them In n strong solution OF formalin,
, one part 40 per cent formaldyhyde to
100 parts water, being sufficiently
strong for the purpose Where large
wounds are made they should be
painted over. This pruning is much
more efficient II done during the DOR
mant season, although cankers should
be cut out whenever they make their
appearance. For the sake OF appear
dnces and for the general good OF the
tree. twig blight should he cut out
every spring. but II will not effect the
progress OF the disease.
No one man or group of men can
ever eradicate this fire blight. II must
be done by concerted action of the
I entire community, as one diseased
, tree Is source Of contagion TO the
entire community Disease will spread
from II as tar MS insects can carry Il
One man may reduce II In his orchard
by proper pruning, but II will appear
from time TO time from his neighbors
Many authorities on FRAT CROWNS
are doubtful as TO the possibility OF
? ever controlling 1t, IL seems. A few
T years ago the famed Rogue River Val.
ey and also the celebrated Hood
River Valley of Oregon. were threat.
I enGd by fire blight The control o.
the disease was taken in hand by al
i efficient man, backed by the entir,
community, and In a couple of years
d no case of the disease was to b,
found throughout the entire valleys
d What has been done In these instan
ces can be done here If II is tried.
b For the benefit of those who's,
neighbors will not prune, Il has beer
G found that scarcity of water, such a,
will prevent rapid growth in the tree
i will tend to discourage the bllgh
from attacking new places, and ma,
A clnnn IL ont of the old