Staunton spectator and vindicator. [volume] (Staunton, Va.) 1896-1916, 1901-07-12
THE APPLE-TWIG BLIGHT.
Professor Atwood Suggests a Remedy
for the Orchard Post.

l noted in your issue of Sunday,
June 23rd, that your correspondent
from Highland county makes some
comments upon blight and other trou
bles of fruit trees. He states that the
growers are very much wrought up
over the recent appearance of blight
or insect, which is at work On the. APP
pie trees. Thinking it may be in
terest to your readers. | write to say
that the trouble which your correspond
ent mentions is doubtless the apple
twig blight, which is now so common
over the State, and has occasioned
great loss for several years past to or
chard growers.
The blight is caused by the same or
ganism which causes the fire blight of
pear. and is known to botanists as
bacillus amyiovorous, the starch de
vouring bacterium. The germ is a
vegetable organism and gains entrance
to the fruit trees, in most cases,
through the blossoms, or at the grow
ing points of the twigs where it at
once sets up a process of fermentation
in the bast tissue, thus rapidly killing
the twigs and branches as far as the
growth of the germ spreads. 1t may
also gain entrance at wounds on the
limbs or trunk, and here causes the
same trouble, though very often not
so marked, and overlooked frequently
by the grower.
On the large limbs or trunks the dis
eased area is marked by a blackening
of the bark, leaving rather distinct
demarcation between diseased and
healthy tissue. The area affected may
be slight, or it may become SO general
as to entirely kill the tree when the
attack is on the trunk. In very many
cases it is of slight extent, and, not be-
ing noticed, is not cut out, and con-
sequently the succeeding year, when
growth starts, the sap-exudes round
the borders of the diseased area, and
carries with it m riads of germs. which
are just commencing active growth.
These germs are carried away by in
sects which visit this exuding sap, and
then visit tn e blossoms, and thus serve
as means of injecting quite generally
the trees in the vicinity. The germs
are also very generally washed away
by dew and rain and borne in the
atmosphere to other plants. The state
ment may help fruit growers to under
stand the life history of this disease
organism.
1t has become such a serious trouble,
that growers ought to observe careful
ly to detect it and cut out in the fall
all the diseased wood with great care,
thus lessening the opportunities for
the dissemination of germs the follow
ing spring. l also think that the thor
Ough use of Bordeaux sprays in the
early spring as given at length in our
bulletins, help to check the dissemina-
tion of the germs on to the new growth
and blooms of other trees. We coat
the limbs and trunks with Bordeaux
spray before growth begins. These
bulletins will be furnished any grower
on application. free of charge.
The "black-knot" trouble which
vour correspondent mentions, can be
very easily controlled by cutting out
the diseased twigs as promptly as they
appear, but where the tree is covered
with diseased linn rs, it should be cut
down and burned. This trouble is
caused entirely by fungus, and the
spores are spread from the knots.
WILLIAM B. ATWOOD,
State Entomologist and PatholOgist.
Blacksburg, Va, June %, 1901.
Richmond Dispatch.