Milford chronicle., 1916-08-11
FIRE BLIGHT OR TWIG BLIGHT
And canLer Of Apple, Pear And Ounce
Fire blight Epidemic IN Nature.

have been recorded from time to time
since its observation, about 1880. In
Delaware, the disease has been active
for some time; Chester, in 1901, pub
lished bulletin So calling attention to
methods of distribution and means of
control. Within recent years the need
of cooperation among orchardists in
the control of this trouble has been
emphasized.
Symptoms.
Blossom blight, fire blight, twig
blight, canker and collar rot, the lat
ter affecting limb and trunk, are all
symptoms of the same disease Twig
blight is the most prevalent and is in
dicated by the blighting. burning-like,
injuries of the twigs from the tips
ldownwards. Blossom blight often de-
velops 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 carried in a
drop OF the sap oozing from a limb
or trunk canker affected with the dis
ease, or in the nectar of a single bios
som. The organism causing the dis
ease is carried to the blossoms and
twigs by insects such as flies, bees,
/ lice and ants. The mouth parts of a
single bee may infiict a thousand bios
SONS 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 liv-
ing 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 attract
ed by the sweetish odor.
Distribution.
The nectar loving insects 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. Spat- |
tering of the bacterium by rain is a |
secondary means of spreading the dis |
ease. Lice and ants may have much /
to do with late twig infection.
Conditions FaVOring Activity of the
Disease.
Excessive rainfall, moist and sat
urated 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
applications of sodium nitrate, in fact
any condition or treatment which pro-
duces 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 re-
-ard the spread and activity of the
disease.
Control.
In all severely infected districts.
control has been possible only by the
cooperation and active organization
)t the orchardists. Such efforts must
be backed by stringent laws govern
ng cases of negligence. Farmer A.
with all the skill and knowledge at
lis command, cannot control the
blight in his orchard, if farmer B,
1cross the road, persists in growing
infested pears and apples that are
oaded with carry over cankers of the
llsease. The bees may readily carry
he disease several miles. It has been
ihOWn that the organisms may live in
loney for AZ hours.
In the face of these facts, it is neces-
ary that all measures must be assist
ID by campaign of education, as to
he cause, symptoms, means by which
he disease is carried over winter, the
manner Of distribution, and methods of
ontrol. Thus far, the most success
ul methods of control have consisted
n cutting out the hold over cankers,
'rior to the ascent of sap in the
pring. One days labor in the dor
nant season in cutting out such cank-
rs is worth a month of labor in sum
ner, when wholesale infection is ram
ant. The equipment for cutting and
consists OF pruning
hears (bOth hand and extension), (
running saw, wide chisel, a mallet, a
PONCE and brush the disinfectant.
which is made by placing one tablet
f corrosive sublimate in a quart of
water, may be carried in a wide y
mouth bottle, or a quart Mason fruit
ar. The small pruning shears may
e dipped or wiped off prior to each ?
Tipping. The cankered areas should =
'e disinfected with brush. Cut at !,
east one-half inch beyond the infec- !
ion on cankers and at least six inch z
IS below the blight areas on twigs and !, I
blossom spurs.
The spraying work done by Profess !,
or McCue in 1907 using Bordeaux on !
Dears in full blossom, shows some pos =
Utilities OF control. However, there
vas injury to the set of fruit. Others :,
re reporting success with spraying. !
the outlook is promising, i
much more experimental work must :
ie done, before any recommendations a
or control by spraying can be given. 4
Thomas F. Manns,