The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1886-06-30
THE P BLIGHT.
The Bacteria Theory as Explained by
Prof. Atkinson.
Raleigh News and Observer.

ANs -" "AO
A few weeks before my departure
from North Carolina my attention
was called to a disease affecting the
apple trees in the orchards of Prof.
Mangum and Mr.. Martin at Chapel
Hill. President Battle also brought
me some infested twigs and said
that the disease appeared to affect
the apple trees pretty generally
throughout the State, and great an
xiety was felt among fruit growers
for it's effect upon the apple crop.
The disease affects theyoung twigs
of one or two years growth, causing
the twig and leaves to die and the
twig to blacken. The disease usually
sets in at the terminal portion of the
twig and advances toward the main
branch. In many cases it reaches
the portion of the twigon which the
apples are borne and of course de-
stroys the young fruit. My first
care was to examine the twigs to be
certain that the trouble was not
caused by a minute insect, which
often bores into the twigs at a bud
vi SIldl1 UIdIlCIlCQ IL SuCCluS OI
the supply Of sap causes the death
of the twig or Of larger insects,
which with their sharp beaks some
times pierce the tender and succu
lent branches and suck out their
juices. A few traces were seen Of
both kinds of these insects, but on a
careful examination of a goodly
number of twigs it was plain hat
these were the chance attendants
and not the cause of the disease, as
by far the larger number of twigs
bore no marks of insects. [ then
came to the conclusion that it vas
what is termed a "germ disease"
caused by the presence Of a micro
scopic plant belonging to the group
Of bacteria.
AS the "bacterian theory" of the
disease known for many years under
the name of spear blight" "apple
blight ETC., was but recently pro-
pounded, and only within the last
year confirmed by experiments that
were not open to criticism, the re-
suits of some of which have not as
yet been published, wished to have
access to the best and most recent
authorities before attempting to give
an account of this subtle and invisi-
BILE foe. That the credulous may not
think this a yarn" spun to while
away the tedious months of sum-
|. mer, | wish to state that the facts
are based upon the Investigations of
~ 20 o,p r,Oc@ nco,,fo o~l on;
entiic workers, and published in
such works as the following, Proc.
Am. Assn Adv. Sci. vol. xxx, 1880,
page 593 Rep. III. Ind. Univ. 1880,
p. 62 Trans. III. Hort. Soc. 1880, p.
157; Am. Nat. Vol. XII, 1881, p. 527;
Proc. Am. Assn. Adv. Sci. Vol.
XXXIV., 1885, p. 295; Bot. Gaz.
Vol. x, 1884, p. 343.
l also acknowledge the kind per-
mission granted by Prof. Prentiss,
Of the botanical department of Cor
nell University, of consulting a re-
cent unpublished manuscript depos-
tied in the Cornell University H.
brary, by J. C. Arthur, of the New
York agricultural experiment sta
llOl, WHICH, cHlUOulcS tIlc IcSulCS Ol
the most recent and careful investi-
cations upon this important subject.
DISTRIBUTION.
The disease is known to appear in
the fruit trees of North America,
east of the Rocky Mountains, and
from Georgia and Mississippi on the
South to Canada and Minnesota on
the North. Thus far it is not known
outside of this area.
HISTORY AND CAUSES
1t was mentioned as long ago as
1917 in the Oldest genealogical work
published by an American author.
In 1926 and 1892 considerable in
jury was done to pear trees. The
great and widespread epidemic of
thepear blight occurred in the year
1874. Though it has never been so
prevalent and extensive in disas-
trous effects, it has appeared in one
place or another at unequal periods
and in varying power ever since,
sometimes threatening to prevent
the cultivation of fruit trees.
Several agencies have from time
to time been advocated as the cause
of the disease. In 1917 Coke thought
the rays of the sun acting through a
moist Or misty air deranged the ply
Biological activities of the tree and
nroJ,oo i H. J