The Wilmington morning star., 1945-11-26
I[AF BLIGHT HITS
@Y BEAN GROWERS

nroducers in North
soyDean are often faced with
.arollna1 losses in their fields caused Isl,
serious io's enotting diseases. The
n leaf ..s spC COMMON of which, ac-
thtse n4o' w Dr.. S. G. Lehman, as
:sciate, ,.nral IN TEX Experiment Station at
Agrcp1II1Ii ra1Ieae, are bacterial blight
state C0lissc and bacterial pustule.
brown aJlv spT, to control any of these
Nstu'sIH;yep ives over the winter on
ts',E s.sassi in field an acaualhtanee ssa charse
sFssA+ .ss their n symptoms ana charac-
tsrstlc's' c's'a,,ssing 10 bacterial blight.
In , aIsra15o lsu'an points out that the
Or. lsHi 1t lives ever the winter on
5.si' 5'ts'' harvested from 0'SeaSe0
plants ,,o goods are planted,
Nas'' I;rs+ SYMPTOMS of the disease
The lll'o ~ the early and loWermost
appear s. OF of III the Young plants as
leaves angular spots, one-sixteenth
hal' iarS ar or more across. These
a al an have ave-, a watery appearance on
g0's '!s'adersjde tr of the leaves and are
The h!sasr;sh ulIJ in color on the upper
Sr'. c..s,ally. the spots increase IN
J., o'auI autiI they are about one-elghth
'ss ~ aHirl inch across, the shape be-
'f su al del dee;nitely angular, and the
comes 9Ias changes through light brown
COW, d.rk brown or black. Each OF
70 os'A a,rt snots has a light green
torder srtt around it. ~
W. ua'Ia. diseased spots appear shiny
~ s,' the underside OF the .lisa leal que que
,,-;a that that have exuded from the
S..r;or ls..r 20 Of the leaf. They are the
n'Sta s.steria that multiply in the leaf
sssues tssr and cause the disease. :,
'IsasS naon number of the diseased
..o+s o+s''r combine, forming large, ir-
sssuarly sss,I shaped dead areas that
,oo ,oon fall out and leave ragged holes
" sv'4 4be a. leaf. The badly diseased
i.,ves fall off prematurely, thus
contributing in some meausre to
reduction in yield.
IS SPREAD OF DISEASE
Bacterial blight is inclined to
,noear first on the early or lower
mos most leaves, DR.. Lehman says, and
,rsdlallv works its way from leaf
| n leaf up the plant until further
Development is checked by hot
weather.. With moderate tempera-
tue and high moisture conditions,
however, the disease spreads to
stems, pods and seeds.
Through the planting of infected
seeds the disease gets to fields
where soybeans have not been
planted previously
In past seasons, the disease has
been quite rare in North Carolina.
However, during 1945 it was found
in a surprisingly high proportion
| Of the Sovbean fields examined.
This indicates that bacterial
blight development is greater in
seasons that are relatively cool,
such as that of 1915, than in sea-
sons having normal spring and
summer temperatures.
As a rule, if the disease is pre-
sent in midsummer it is relative
y far down on the plants and thus
often escapes notice. In addition,
it is easily confused with the more
conspicuous midseason disease,
bacterial pustule.
DR.. Lehman points out that at
tempts are being made to deter
mine the relative resistance of diff
ferent Soybean varieties to the bac-
teflal blight. And at present, the
varieties most commonly grown
seem to carry considerable resist
I ance TO the disease.
However, he urges growers not
10 use seed that has been har-
vested from fields known to be
injected with bacterial blight.