The Yakima herald. [volume] (North Yakima, W.T. [Wash.]) 1889-1914, 1906-09-19
THE PEAR BLIGHT
AND ITS CONTROL
EARL HISTORY AND NATIVE ORIGIN
Hest Plan In 10 Cut Out Hold over
Blight In the Fall and
Winter.
Methods Of Control of Pear Blight.

IatHtI the lUlnouH LOT confirming IL
may be divided into two classes. primary
and secondary.
The main method OF treating this dis.
ease consists in cutting out, thoroughly
the hold over blight in the fall and win
ter II this is thoroughly done il leaves
no opportunity for additional advantages
from amy of the secondary methods.
As may he seen by referring to the
factors influencing HE disease. the pres
ence ol the germ is of primary import
ance. Ii the pearl blight germ is not
present in the orchards, there can be no
blight. While cutting ont the hold-over
blight might seem to he comparatively Il
simple operation, yet, in actual prac-
tice, it is by no means very easy thing
TO do. 1t requires careful. close. thor
ough work. The irregular development
Of the disease A. has been pointed out
by which il runs down on one side of the
limb or body and not on the other often
led to failures. While the disease in the
top is very easy to handle, and any one
who looks at all closely can not only de-
tcct it. but readily remove the infected
branches. the disease on the bodies is
often hard to see, especially on old trees.
whore it is covered by rough bark.
The gum exudes when it is present.
gives Il clew TO many otherwise obscure
cases \ dead water sprout or fruit
spur no matter how tiny it may be.
leads To detection of Il case. Sometimes
these have been broken off or careless sly
cut off without following up at the base
Sometimes there is infection without Il
water sprout at all. and such cases are
the hardest to detect. unless the gum
has exuded. Where there is large
quantity OF blight removed from the or
chard. necessitating a great deal OF la
hor, ii has proved necessary in every
case to 90 over the orchard critically. or
perhaps we may say leisurelv. on dry
sunny day. when there is good light. and
find the few cases that have been missed
No matter how thorough the work. this
careful inspection has proved extreme
~ important. Not only should thu work
he inspected Immediately following the
general cleanup. but some one with
keen. wcll trained eyes should look over
the trees several times through the win
ter. \ special effort should be made TO
find out when there is new exudation
Of gum. This may follow any warm.
mild spell in the winter, probably when
there is a wide range between the day
and night temperatures. Such condi-
lions are known to affect the flow of
sap in the sugar maple and other trees.
final inspection should he made Just
before hlOssoming time. To catch it he
hast moment in case il has been over
looked. After the blossom period has
passed. 50 that the blight has had time
to develop. if a colony of blight is found
IN the orchard. careful examination of
Til colony will generally result in the
finding Of a case of hold-oy blight in
the center from which all the trouble
may be traced.
After experiences of this kind. we
may expect the California orchardsts to
be much keener in their final inspec-
mons. OF course in such thorough Grad
ication work. the problem is to find the
last cause. for with skillful work case
Of hold-over blight found means an in
lection center destroyed.
In all the cutting ont. strong disin-
fectant should be used to wipe off the
tools after cutting into the blight virus
aud to wash off the wounds made bv
the Instruments Otherwise it is pos
7ibe TO infect the blight in the cut sur
lace and even TO carry ii on the pruning
tools, In the majority of cases. in dry
weather. infection would not result
from The use of pruing tools. This is
especially tre in the late summer or
early fall On the other hand. by numer-
Gus tests, | have demonstrated that
blight punctmed into the feshv bark in
1
through the winter and result in fine
case Of hold over blight the following
-pllng For this disiniectant. the best
thing 70 use is a solution of corrosive
snbllmate in water, one part to one
thousand Tablets may he obtained
from the drug store which are of CON
venient size for making this solution
W hen practicable. use rain water or dis
illed water. as the slightly alkaline
waters IN dry countries tend to precip
tate the poisonous mercurial compound
Also use a glass or otherwise chemically
clean body. as a tin can or other metal
eontalner may react on the mercury and
remove the poisonous principles.
corrosive -nblimate OF mercuric chlor
ide kills the pear blight germ in solution
IN water when it Is diluted to one nart
TO ton thousand. Therefore. the above
formula is well within the limits. II
requires strong solution OF earbolic
aoid in water. so that it i distinctly in.
Terror. to the subimate The latter i.
n fact. by far the best germicide avail
bic for this work Caution, II i n
deadly poison when swallowed. n
should, therefore, be marked poison.
and the greatest care should be taken
~ emptying the bottles when return
ING 10 the house. or otherwise keepinp
both the bottles and The solution away
from children or unsuspecting persons.
Tablets OF sufficient strength TO give
one 10 one thousand solution. when
added TO a pint OF water. usually cost
cent apiece. So that the expense is
insignificant 1t i good plan to use
a sponge. either fastened by a string
two feet in length to ones clothing. ar
tied to the end Of a stick. and thorough
~ wipe off the instruments and the
wounds left on the tree.
md luuIouSl usqN .ueId pooS 81 ar
ners are in the orchard, to make them