Sharp County record., 1918-08-30
CONTROL SWEET
POTATO WILT
Wiz May Be Detected First sy slight
SsllswIns et Upper Leaves.
BY n r. Ensign, Patholog1st, Extsnr
sion Division, q. OF A.

The loss cccasioned by sweet po-
tAto wilt( also known al Stem Rot,
Blue Stem and Yellow Blight in
arkansas last year was estimated TO
bs $50, 10000. This tremendous loss
Ia to be regretted the more because
It might have been largely prevented
by following a few simple rules.
Wilt may be detected first BY a
slight yeIloving Of the upper, younger
leaves. This Is quickly followed by
the willing Of part or OF the entire
plant II the stem of the diseased
vras bs pinched open II will show a
hlacksned center. This blackened
arsa may also extend into the roots.
0bysously, n these potatoes are used
tsS seed, the sprouts which spring
f,cA than are nkely 10 be diseased.
fas diseased seedlings in the hot
bed sksv the same symptoms as
those asseribed above. The blackensd
interior OF the stem gives the white
stem . purpiish east.
TsrtHizsr win Not Control Wiz.
u has been shown that the appli-
cation Of any amount Of fertilizer Ia
OF no value in the control of the dis
ease. Neither Is spraying of any value
since the fungus gains entrance
through the roots OF the plant For
this reason seed selection is an et-
fective means OF control. Disease
free seed may be procured in the fall
at digging tim, while the potatoes
are still attached to the vines After
the potatoes are dug there is no way
Of distinguishing the diseased from
the healthy roots. Each selected
hill should show no blackening OF the
vine when split open. OF course 4
heavy FROST prior TO digging win
make selection difticult as this will
also cause q similar discoloration OF
the vine The selected seed should
be stored Ia baskets or crates 10 pre-
vent contact with other potatoes.
In the spring Just before bedding,
the seed should be treated for five
TO ten minutes by immersing them
In a solution made by dlssolvlns one
ounce Of corrosive sublinats TO eight
gallons OF water. They should then
be rinsed In water and dried before
bedding
Clean Soil Must Be Used.
After disease once occurs In a soil,
the fungus will live over In this
soil year after year. This soil should
not be used In the bedding of the
seed. Soil upon which diseased pota-
toes are thrown or upon which man
ure from animals fed with the dis
sassd roots (unlsss previously contedl
should IN no case be used sither for
the hotbed or for field planting. Hot
bed soil once used should be hauled
away and the frames and soil around
them should be- thoroughly soaked
with q solution OF tormaldehyde made
by mixing one pint OF formalin 10
thirty gallons OF water. II is best
that this treatment be repeated after
tvsnty.tour hours.
Tn. soil for the hotbed should be
obtained from some part OF the farm
where there Is no possibility Of its
being diseased with the wilt fungus.
Sand from the wood.lot Ia good.
Throw or the upper six inches and
use only the subsoll The wagon used
10 haul the diseased refuse away
should not bs used for bringing IN the
new soil unless cIeansed bp the for
maldehyde solution.
A crop rotation of three 10 five
years should be practlced, for n 10
known that the fungus remains J.,
m. soil for several years.
euJs. 10 Prevent Disease.
Siipsesding, n the proper santa,
tion IL observed IA the operation, 10 u
successful way oi producing diseased
free seed The rules are az follows,
quoted from Farmers Bulletin III:
I, The cuttings should be made
from healthy vines,
Q. The cuttings should be planted
on new ground or on ground on which
sweet potatoes have not been grown
for AZ least six years
T. The potatoes produced by tho
cutting should bc picked over and
dislrfeeted In the spring before bed
ding, according 10 directions already
xivsn.
l. The seed potatoes must be bed
d.d IN a hotbed prepared according
IA the directions given above.