Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1915-05-30
VIRGINIA'S ORCHARDS
AND ORCHARD BLIGHT

growth the hold-overs exude shiny
drops OF a summy exudate. These drops
are composed chiefly of the blight bac-
teria. Bees or other insects blunder into
these drops. get themselves covered
with bacteria, and. on visiting the bios
SONS later. start the trouble. The bac-
!. terra multiply at An enormous rate In
the nectary Of the flower. and from
that point may he spread by bees to
thousands OF other blossoms in the
space of twelve to forty-eiRht hours
Hence the epidemic nature OF the at
tack and the vary industriousncss OF
the bee lends much to his efficiency as
a. blight distributor. Once established
in the blossom the bacteria spread with
deadly effect through the soft tissue of
the young fruit into the cambium and
bark below. The progress of the dis
ease continues until the older and hard
er wood Of several seasons age is
reached.
In pear trees such is not the case, and
the disease may spread through young
and old wood alike. sometimes killing
trees to the very base. An apple, usual
~ a Ben Davis. occasionally meets
with a like fate. 1t is such trees whose
large branches or trunks blight easily
that offer the conditions necessary for
the existence OF "hold-over canker."
Smaller branches and twigs dry out SO
rapidly in winter that the germs within
them arc killed.
HOW THE BEETLE
GETS IN IT'S BAD WORK
Occasionally blight is TRANSMITTED by
bark beetles directly into large limbs.
or by plant bugs or other sucking in
sccts into the soft tissues or water
sprouts. The watery, succulent growth
of the water sprouts offer ideal condi-
tons for the development of the dis
ease. and from them II spreads TO large
branches. Water sprouts should not.
therefore, be allowed to remain on the
trees.
Control-obviously 1t is Impossible
TO successfully spray for twig blight a
any spray material applied to unfertil-
lied flowers would kill the pistill and
prevent the formation of fruits. APP
piled later the spray would be worth
less since the bacteria are inside Of
the skin or bark and would not be
reached By the poison. Other means Of
control must be sought.
1t is not pra ct!cable to prune off all
infected twiEs. even II We disregard
the loss sustained by the death of the
blossoms so the logical thing to do is
TO destroy the sources OF infection
These are the hold over cankers" on
apple and pear trees bliEhted the pre-
"ious year. N!ne-tenths % such cank
ers occur on pear trees, especially on
Bartlett, Sickle and lie Conte. The
best way TO deal with holdovers is TO
should be kept throughout the sum-
mer and fall and all pears trees which
blight badly should be promptly
chopped down and burned.
In many cases. where pear and apple
orchards adjoined, il has been easy to
see that the amount of twiE blight on
the apples was inversely proportional
TO the distance from the pears. II YOU
spare the pears. be prepared 10 take
the consequence. The saw should be
used promptly, limbs should always be
cut of at least two feet below any
signs OF the disease and the saw inn
mersed IN 1900 bichloride OF mercury
between operations. No half way job
Will do, and in late fall or winter il
is wise TO go carefully over the prem
ises again on the search for hold
overs.
The growth OF the bacteria in the
tissues of the soft inner bark causes 4
water soaked appearance and finally a
hlackening and shrivelinG. During the
growing season and sometimes also in
winter this bark has sour fermented
door when cut away with knife.
When the germs cease TO spread rapid
~ in the tissues, sharp line, often A
deep crack, separates the diseased from
the healthy bark the edge OF the
wound This condition is most notice
able in winter
Cooperation with your neighbors is
highly desirable in waginS campaign
against twir blight and incidentally
against pear blight Community efforts
will give the best results, and If il
is not possible 10 destroy infective
material in the neighborhood the next
best thing is to render the apple trees
as resistant as possible. Fast grow
ing, sappy trees blight worse than
slow growing trees. and II is therefore
advisable 10 suspend all cultivation
and application OF fertilizers, especi-
ally heterogeneous fertilizers.