The herald and news. [volume] (Newberry S.C.) 1903-1937, 1912-05-31
) CLEMSON EXTENSION WORK.

o CLEMSON EXTENSION WORK. o
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In all of the places visited in the
wilt infested sections of the State we
have found root knot very prevalent.
In fact root knot and cotton wilt seem
to go hand in hand. Where one oc-
ours the other is. nearly almost al
ways found. Either trouble is bad
enough by itself, but where they both
occur they frequently destroy whole
crops of cotton and cowpeas.
Rot knot is caused by small nema-
todes (eel worms) which bore into the
roots of the plants and irritate the It's
sue, causing enlargement of the point
attached. These enlargements vary in
size from almost nothing to the size
of a pea and sometimes even larger.
When cut open and examined under
microscope these knots are found to
be full Of the tiny nematode worms.
These live over the winter in the old
roots and in the soil, and begin work
again the next spring in the young
roots. If the crops that they live on
are kept off the land for several years,
the nematodes are starved out,
We get rid of the root knot then by
rotation; i. e., We grow on the infest-
ed land only those crops on which the
nematodes can not live. Corn, oats,
wheat, rye, Iron cowpeas, peanuts and
velvet beans are safe crops to use in
such rotation. Sweet potatoes, cotton,
cowpeas, tomatoes, okra, cucumbers,
watermelons, beans, tobacco, and a
number of other crops are subject to
root knot and are not safe to plant
on infested land.
Wilt is caused by parasitic fungus
which grows in through the roots of
the plants into the stems, and plugs
up the vessels which transport food
and water back and forth to the diff
ferent parts of the plant. When these
vessels are clogged up the plant willis
and dies. The fungus which causes
the trouble lives in the soil and will
remain alive there for number Of
years even when cotton and peas are
left off the land. The only way to
control wilt is by the use of resistant
varieties, varieties which are almost
wilt proof The varieties of cotton
which are resistant to wilt, however,
are by no means free from root knot.
Root knot encourages wilt because the
fungus which causes wilt easily en-
ters the roots through the wounds
made by the nematode worms. The
first step then in controlling wilt is
to get rid of the root knot.
Now the ordinary farm practices
which are followed in this State tend
to encourage both wilt and root knot.
In the first place, the wilt which at
tacks cotton and peas is practically
the same, and the root knot which is
common on cotton, peas, potatoes and
tobacco is exactly the same. Cowpeas
which are used in every imaginable ro-
tation are subject to both of those,
troubles which prove so disastrous to
cotton, so where We use the common
varieties of cowpeas in our rotation
We are encouraging both of these dis
eases. There are two varieties of cow
peasS however, which are free from
both root and knot wilt. These va
rieties are the Iron and the Brabham;
and it is with the view of calling at
tention to these and emphasizing the
necessity for their more general use
~
that this article is written.
The South Carolina farmer can not
farm without cowpeas, yet where wilt
and root knot occur he can not grow
the common varieties; and it is not
safe for him to plant them even where
they do make some growth, because
they encourage the same disease of
cotton 1t is wise then to secure and
grow the varieties which are resistant
to both Of these diseases-the Iron
and the Brabham varieties. These va
rieties are quite generally grown in
some sections of the State, but are still
unknown to many farmers who are