The morning news. [volume] (Savannah, Ga.) 1887-1900, 1889-06-05
GENUINE EAR BLIGHT
THAT IS THs5IsEAsE ON THE
SOUTH GEOFIA PEAR GROVES.

Of the Agricultural Department =
Extent OF t. Blight-It May Affect
the Trees 70 or Three Years and
Then Disauear-No Known Remedy
for the Truble-The Crop This Year
Not Maternity Injured.
THoMAsvnLt5A. June Ain response to
several lettersiom pear growers and from the
chief officials the Savannah, Florida aud
Western railwr. stating that an unknown dis
ease was dam;iag the LsConte pear groves of
South Georgiand North Florida, the writer
was commissised by the secretary of agrieul-
ture to invesgate the matter. Accordingly
the writer haseen at work in the pear groves
With microscoe and scalpel. AS far as the cause
Of the diseaseis concerned satisfactory con
Clusions have BEN reached. The information is
ven througHhis medium in advance OF any
government rport on account Of the special
present demaH o. Information on this subject
Hon Edwin NlleJts, the able Assistant Secre-
tary of Agriculture, who has charge of the sci
entifc work # the department, SAID to the
writer when sbrting: Il desire particularly to
R.d the growin industries OF the south and the
KeS1, and as yd are going south be sure and
make your Investigations as thorough as pos
bible. Give all the information you can con-
terning the difficulty, and assure the people
that the department of agriculture at Washing
ION is wiling . aid them in every way in its
bower ! wish to thank the people where /
laye been forthe many favors received, and am
Under specisl obligations to the Savannah.
Florida ana Western railway for opportunities
" making this investigation thorough
THE MALADy.
The disease which is damaging the LeConte
bear trees in South Georgia and North
Florida is the genuine pear blight 1t is the
anne obscure and destructive disease that has
been the bane of pear growing in the eastern
tates for nearly century, and that is now
tnown TO occur more or less wherever the pear
\ grown in the United States.
WHAT IS PEAR BLIGHT?
Fhe blight in the pear tree and few other re-
lied fruits is a specific disease It is the work of
abicrobe. In other words. it is due to a species
d bacteria which lives in the pear twigs anu
DIX as a true parasite and kills as a result of
Vpresence The terms blight" '.rust'' and
lie back are often used rather vaguely to
lme any of the diseases or injuries to vegeta-
ion. But in this case we are dealing with a
Ipecific disease which is peculiar TO the pear
Ind its allies. This is by no means the only dis
ase of the pear tree. VonToumen, a German
pianist, enumerated twenty-three species
I fungi that are known to occur on
1e pear OF these the greater number are
rue parasites which live at the expense of the
lar and are more or less injurious to it. OF
tese pear diseases caused by fungi only four
Ave done sufficient damage in the eastern
Nted States to attract attention Preparations
Nre made TO study up the trouble in the I,e-
Cpte orchards in case it should be any one of
Else or something new, but the first stride of
I'll diseased tissue which was placed under the
horoscope revealed immense numbers of the
Characteristic microbes OF pear blight. Abund-
any repeated trials always gave the same re-
SUI and the external characters of the disease
$50 pronounced as to leave no possible
dobt.
HISTORY.
PNbably no disease of plants has been more
dlScksed and written about than pear blight
Ihelrst positive record of the occurrence of
thI disease is on the highlands of the Hudson
u p} The first American book on fruit Gull
xuL published in 1917, contains a chapter on
blht in the pear Since that time there has
b5n no end of articles in horticultural papers,
sASs and Journals, especially in recent years.
eforts of theories aud specglations have been
l9ged in by horticulturalsts and fruit
gferS concerning the cause of the disease.
theories are usually as different as
ca individuals in whose brains they
orlnated. Some attributed it to the
VIZ of insects, others to freezing and frozen
Sa4 Some thought it was due to an over supply
OF p, while others to a deficiency of the same.
Bult was reserved for Prof Burrill of the
Unhrsi;y of Illinois to discover the real cause
OF lght This he did in 1890 Prof Burrill's
rentkable discovery of the bacterial nature of
IhlSiisease forever put an end TO the wild
speqations and theories concerning it and
praacally Cancelled ali that had been
TrIth previously concerning the cause
OF light. The observations of the
othetwriters as to mode of occurrence
and istribution still remain of value. Ia
1858 pf. Burrill published name and descrip-
Lon lr his new species OF microbe. 1t is
no" ADwn to botanlSts as MicrOcOccus anu
toH0T1 Burrll. From 1884 to 1887 Prof. Ar
tnur, 9the New York experiment station con-
Quoted very careful series of experiments In
the silly of pear blight. He fully corrobo-
rated lpf. Barrill's work, and discovered valu-
able mel facts about the disease. Prof. Arthur
c&rrledut his experiments with more COM
pleteneA than had been done before, and as
result y proof that the microbes cause the
DAght Is perfect as any biological demonstra-
Ton caHver be. Still, in the light of all these
ulscoVefs, the only remedy known is to cut
out the seased parts.
EXTERNAL APPEARANCE.
Unfortunately this is already too familiar to
many riders In general the blight may be
recognizh as a rather sudden dying back of the
EhdS OF he branches without any evident cause
lhe leaes, shortly after the death of the
pranchey die as a natural result, and the dead
ulanchei present about the same appearance as
limos ttht are accidentally broken off. The
4eshly 1lled twigs present rather blackened
Y moresoggy and moiSGer appearance than q
YAeh wig: frequently there is a gummy
quotation given Off By far the greater number
the points of infection are the blossom spurs
lhearP every instance the disease can be
siced TO q blossom cluster as the starting
Plnt In the greater number of cases the
npung spurs and tips of the branches are
UNITED, and that is all In the more severe
tIatS 1t continues to spread downward, killing
Il
1Iepently runs around large branch from a
usefed spur, and girdles it completely All
%ooN TINS eventually dies, although the leaves
may ernaln green for some time. The disease
PLoSrSses on the main limbs only in the inner
U UarT aNd cambium layer, this being the only
I riv3l pat II appears on the trunk and main
THUS dead, slightly sunken patches.
bv tba "Gk OF the previous year is told
~ Cne oad weather-beaten branches In by far
Tue iafge1 number of cases of dead twigs and
Ionches examined the disease had Stopped
tpoSreSsnt and crack has formed between
one nsaIthy and diseased portions. The tree at
S Slce iormsl a layer of cork or bark over the
reraou pay thus healing UP the wound. A
d ill Aaoleease is frequently seen in which the
tb haas spretd in larger patches on the trunk in
jaTa ,.ner oak, but failed to kill the cambium
80 49, next the wood. Here new bark is seen
t6at forming underdeath the old. The fact
st oI9 ulSeaae in nearly every instance has
T progressing leads to the belief that no
on damage will be done this year The dan
fn seems to be over until the period for nfec-
Non next spring.
THE MICRoBE OF PEAR BLIGHT.
"a 1ne lncrobe which causes pear blight belongs
oil 81 CUP or plants which are the smallest of
the wing things. Further than this it is one of
rao smallest Of its kind. Each individual is q
NH " spherla simple, colorless, vegetable cell
nao. ~ power OF locomotiQn. 1t spreads in the
co co. ohly by increase in numbers. 1t is very
MI error to think that bacteria are ami
WI W.T. rms is not So for they are plant cells
s dirn cell wall of cellulose. Some idea of the
naroei. lnflnitesimal size of these minute
tissues may be gained when it is stated
s I'' u would take over 90 900 of them placed
Tttia3 y SIDE to reach an iuch and yet these
w. ME beings kill large pear trees. TGey make
~ III numbers what thew lack in size Thesa