Middletown transcript., 1916-07-15
The FIRE BLIGHT
Frequent Outbreaks Occurred In
This County Since 1889
THE REAL CAUSE AND ORIGIN

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quent outbreaks of this disease have
been recorded from time to time since
its observation, about 1780. In Della
ware, the disease has been active for
some time. Chester, in 1901, published
bulletin So calling attention to methods
of distribution and means of control.
Within recent years the cooperation
among orchardists in the control of this
trouble has been emphasized.
Symptoms-Blossom blight, fire blight,
twig blight, canker and collar rot, the
latter affecting limb and trunk, are all
symptoms of the same disease. Twig
blight is the most prevalent and is indi-
Gated by the blighting, burning-like in
juries of the twigs from the tips down.
wards. Blossom blight often develops
into twig blight and twig blight may
develop into cankers such as limb and
trunk injury. Bacteria washing down
from the twig and blossom blight often
cause collar rot.
Cause and Origin-The cause which is
bacterial was discovered by Burrill of
Illinois in 1878. The organism is very
minute; a million or more may be car
ried in a drop of the sap oozing from a
limb or trunk canker affected with the
disease, or in, the nectar of single
blossom. The organism causing the
disease is carried to the blossoms and
twigs by insects such as flies, bees, lice
and ants. The mouth part CT a single
bee may infect a thousand blossoms on
one trip.
How Carried from Season to Season
We have no evidence whatever that the
organism is carried over in the soil.
On the other hand, we have abundant
evidence that the disease carries
over in the cankers on limbs and
trunk and that, at the first ascent
of sap in the spring, there Oozes
out an insipid gum from such cankers;
this gum contains billions of the living
organisms, which may actively cause
disease. This flow of gum takes place
just prior to blossoming when nectar is
scarce; the insects in search of food
visit these flows, being attracted by the
sweetish odor.
Distribution-The nectar loving in
sects having contaminated their mouth
parts from visiting these carry over
cankers which are actively oozing, will
visit the flowers as soon as they open.
Then begins the wholesale distribution
of the disease, resulting in the general
blossom and later the twig blight so
common the present season, Spatter-
ing of the bacterium by rain is a secon-
dary means of spreading the disease.
Lice and ants may have much to do
with late twig infection.
Conditions Favoring Activity of the
Disease-Excessive rainfall, moist and
saturated atmosphere, heavy dews, and
long continued cloudy weather are ideal
conditions for rapid progress of the
disease Thorough cultivation, the use
of manure, the turning under of heavy
leguminous cover crops, heavy applica-
tions of sodium nitrate, in fact any con-
dition or treatment which reduces rapid
and succulent growth of wood will favor
the development of the disease in the
tissues. On the other hand, drying
winds, droughty weather, and cultural
treatments which tend to harden the
wood will retard the spread and activity
of the disease.
Control-In all severely infected dis
tricts, control has been possible only by
the cooperation and active organization
of the orchardists. Such efforts must
be backed by stringent laws governing
cases of negligence. Farmer A, with
all the skill and knowledge at his COM
mand, cannot control the blight in his
orchard, if farmer B, across the road,
persists in growing infested pears and
apples that are loaded with carry over
cankers of the disease. The bees may
readily carry the disease several miles.
1t has been shown that the organisms
may live in honey for At hours.
In the face of these facts it is neces-
sary that all measures must be assisted
by campaign of education, as to the
cause, symptoms, means by which the
disease IS carried over winter, the man
ner of distribution, and methods of con-
troll. Thus far, the most successful
methods of control have consisted in
cutting out the hold over cankers, prior
to the ascent of sap in the spring. One
days labor in the dormant season in
cutting out such cankers is worth a
month of labor in summer, when whole
sale infection is rampant. The equip
ment for cutting and disinfecting con-
sists of pruning shears, (both hand and
eXtension), pruning saw, wide chisel,
a mallet, a sponge and brush; the disin-
fectant, which is made by placing one
tablet of corrosive sublimate in a quart
of water, may be carried in a wide
mouth bottle, or a quart Mason fruit
jar. The small pruning shears may be
dipped or wiped off prior to each clip
ping. The cankered areas should be
with brush. Cut at least
one-half inch beyond the infection on
cankers and at least six inches below
the blight areas on twigs and blossom
spurs
The spraying work done by Professor
McCue in 1907, using Bordeaux on
pears in full blossom, shows some pos
sibilities of control. However, there
was injury to the set of fruit. Others
are reporting success with spraying.
Although the outlook is promising,
much more experimental work must be
done, before any recommendations for
control by spraying can be given.
Thomas F. Manns,