Tensas gazette., 1917-12-21

covering period Of four years to de-
termine whether wilt is carried by |
the seed have given negative results. |
Wet Seasons Favor Wilt.
1t is a fact recognized by most farm
ers in wilt territory that the disease
is more severe In wet seasons ana
less injurious in dry years. Abundant
soil moisture favOrs rapid growth or
the cotton plant. and likewise fur
nishes the best conditions for the de-
velopment Of the fungus. For this rca-
son also, new cases of wilt are usual
ly most numerous just after rain.
Root-Kno Makes Wilt Worse.
When roOt-knot occurs with wilt,
the amount of loss Is very materially
increased. and different methods Of
control are made necessary. Cotton
is moderately subject to rOOt-knot,
which reduces the yield In hundreds
of fields whose owners are Ignorant or
| it's presence. The wounds which the
nematodes make in the roots furnish
points of entrance for the wilt fungus,
which then completes the destructive
work. Whole fields are thus pract-
cally annihilated, the farmer losing
not only the crop but all the labor OF
planting and caring for 1t, when by
the use OF proper rotations a paying
crop could have been grown. Even
the wilt-resistant varieties bred by the
department of agriculture are not en-
tirely resistant to root-knOt and should
not be planted on. land infested by ne
matodes until such fields have been
rotated to reduce the number of these
eelworms.
How to Recognize Wilt.
When the leaves of cotton plants
wilt and fall without any apparent rea-
son, black-roOt, or wilt, is to be sus-
pected. If a freshly wilted plant Is ex-
amined and the interior Of the stem
or root is found to be Drowned or
blackened, the disease is almost sure
to be wilt. Certain kinds of dwarflng
of the main stem are likewise charac-
teristic of wilt, particularly reduc-
ton In the length and shortening Of
the distance between the branches.
This is often accompanied by the nor
NAL development Of one or more OF the
basal limbs, due to partial infection.
Measures for Control.
Carefully conducted experiments
have shown that late-planted cotton is
as severely attacked by wilt as that
put in at the usual time. Furthermore,
it is a commonly accepted fact that
late-planted crops seldom produce as
{ large a yield as those planted early.
In boll-weevil territory, cotton must
d be planted early to get ahead Of the
weevil.
Z Fertilizers and Fungicides.
Cotton wilt cannot be controlled by
I the use of fertilizers. Neither kainit
acid phosphate, salt, lime. potash, nj
trate of soda or any other fertilizer
L used alone or in combination has giver
e any relief. In some cases Of slight in
e festation the use Of stable manure ha:
e been Of benefit, and its use In TIT
y breeding of wilt-resistant varieties ha
been found of assistance.
l. The use of soil fungicides Is too ex
pensive to be worthy of consideration
$ Moreover, large quantities of numer
r Gus fungicides have been used on wilt
)f infected land without reducing tn
amount of the disease.
l. Rotation of Crops.
Is The fact that the wilt fungus ca
le live for q long time on the decayfn
y organic matter in the soil renders
Is well-nigh impossible to starve out tn
disease by crop rotation. Root-kno
Ie on the other hand, can be controllc
Is by rotation. Because Of the almOs
IN universal occurrence of root-knot wit
Is wilt and because Of the fact that m
X. matodes increase the severity Of tn
er latter disease, rotation of crops, con
~ bined with the use of resistant vari
~ ties. becomes of vital importance
III the control Of wilt.
u. Growing Resistant Varieties.
u Wilt when occurring alone can
ne successfully controlled by the use I
IL wilt-resistant varieties Of cOttO
H. When roOt-knot occurs with wilt, cr'
rotation must be combined with Il
b planting of resistant varieties. Tho
TN sands of acres of these varieties ha'
Dy been profitably grown on wilt-infet'
es land every season for the last eight
Id ten years. Their use on diseased laI
or has long since passed the experimer
ge al stage, and each season sees the e
ge tension of their planting to new ter
'd- tory.
Ito Among the wilt-resistant varieties
m cotton that have been found useful a
om Dixie, Dillon and a number Of hybr
ed resistant strains. Additional resista
ar strains are being developed by t
zen United States department Of agric1
MT ture, state agricultural agencies a
SITS individual co-OperatOrs.