Tensas gazette. [volume] (St. Joseph, La.) 1886-current, 1917-08-10

prepared by the United States Depart
ment of Agriculture)
The sweet potato is attacked by a
number of fungus diseases, some OF
which attack the vine and others the
tubers. Some of these diseases devel-
op and cause losses i'm the field, while
others appear after the potatoes are
placed in storage. With a knowledge
of the different diseases and how they
spread, with a proper system of crop
rotation, and with care in the selection,
handling and bedding of seed potatoes,
much of the loss from diseases can be
avoided.
Stem Rot (Wilt, Blue Stem, Yellow
Bliqht).
This disease is caused by the fungi
Fusarium batatatis and Fusarium n.y.
peroxysporum. The stem rot is first
noticed as yellOwish discoloratiOn or
the leaves at the tips of the vines. III
the stem is pinched open it will be
found blackened inside. This discOlor-
alton often extends 3 to feet from the
hill, and is soon followed by whiting
and collapse of the vine. Later the
stem ruptures and the surface becomes
blackened and rotted, though the plant
may produce a few potatoes. The fun
gus causing the disease may invade the
potatoes also, forming a blackened ring
about a quarter of an inch below the
surface.
Control.-The fungus causing stem
rot lives through the winter on dead
sweet-potato vines left i'm the field and
in potatoes put in storage. The dis
ease may be spread by insects, farm
animals. farm implements and wind, or
| by dumping discarded diseased pOta-
toes on the fields as fertilizer either
before or after feeding to live stock.
Stem rot may be controlled by
proper selection and handling of seed
potatoes, by using clean hOtbeds, and
by crop rotation. The fungus causing
stem rot invades the potatoes; there
fore, if plants are produced from these
potatoes, they will become diseased. 1t
is very hard to detect the disease on
young plants when pulled from the bed,
therefore many diseased plants are set
in the field and continue the spread of
stem rot. 1t is necessary, then, to have
seed potatoes free from disease, and
these can be secured by growing seed
from vine cuttings on new land or In
selecting the seed in the field at time OF
digging In selecting the seed each hill
should be tested by splitting the stem
and if no black streaks appear the pO-
tatoes may be used for seed. This Sc
lection should be done before frost has
blackened the vines. The seed potatoes
should be placed In the storage house
separate from other potatoes.
Dipping Seed.-In the spring at bed
ding time the seed potatoes should bt
dipped for to 10 minutes in a solution
of corrosive sublimate, made by dis
solving one ounce in eight gallons OF
water The solution should be placed
I'm wooden cOntainer, such as kes
or barrel, and the potatoes may bt
dipped by using burlap sack or wire
basket After dipping the potatoes
should he rinsed I'm clean water and al
lowed to dry before being bedded. Thi.
dipping will not kill the fungi that ma.
be in the potatoes, but 1t will destro.
all spores on the surface.
Preparation of the Hotbed.-The us
Of the same hOtbed year after year i
probably one of the chief ways o
spreading stem rot. In localities wher
the disease is prevalent the soil in tn
hOtbed should be changed every year
and the framework Of the bed an
surrounding ground should be thor
Oughly soaked with 81 solution Of on
pint of formaln to thirty gallons o
water or a solution of one pound O
copper sulphate to twenty-five gallon
of water.
New soil or sand for the hottie
should be procured from field wher
. potatoes have never been grown. A
rich dirt is not necessary for the bee
sand may be procured from a sand ban
and thus danger of infection consider
ably lessened. The same wagon @
tools used In hauling away infected dill
should not be used for hauling in ne'
sand. unless they have been disinfecte
, with a solution of formalin or cope
sulphate. of the strength previOusl
mentioned.
In localities where sweet-potato di.
. eases are prevalent fire-heated hotbed
|, are preferable to those heated by m,
: nure on account of the chances tha
the manure may have become infecte'
Discarded diseased potatoes usual
: find their way to the manure pile, an
:, If any diseased potatoes are left an!
where about the farm. infected part
may be carried around on the feet
, chickens and other farm animals.
Prevent Disease and Mortality.