Tensas gazette., 1917-12-21


prepared by the United States Depart
ment of AgricultureO
Throughout the sandy sections OF
the cotton belt, where cotton wilt and
roOt-knot occur every year to an In
creasing extent, there is urgent need
for fuller understanding of these dis
eases and the important relation they
bear to each other and to the farm
er's margin Of profit. Wilt occurring
alone causes serious loss to the cot
ton crop, not only by killing large
numbers Of plants, but. further. by
stunning very many others and thus.
greatly reducing the yield. Cotton
root-knot by itself causes a dwarfing
of the plants and consequent de-
crease in yield over large areas. OFTEN
the farmer does not notice this or at
tributes it to an unfavorable season,
poor soil, lack of proper fertilization,
or some local condition. Where these
two diseases occur together, which is
frequently the case, the loss is often
so great that it becomes well-nigh i'm
possible by the usual method of cultl-
walton to grow the principal money
crop of this section without an actual
loss. In other words, wilt and root
knot then become the most important
limiting factors in the production OF
cotton. To remedy this condition, the
whole scheme of farming must often
be changed and planned with special
reference to the control Of these high
ly important enemies of the cotton
crop.
Rotation Of crops for the control OF
root-knot and the use of varieties OF
cotton resistant to wilt are more es
sential to the profitable growing OF
crop In badly diseased areas than fer
tilization or cultivation, although
these are of great Importance.
Cotton wilt and root-knot occur to
greater or less extent in every cot
ton-producing state from North Caro-
lima TO Texas. The areas where VIII
Is of most general and serious occur
renee are southeastern and eastern
South Carolina, southwestern Georgi'
and southeastern Alabama.
On the sandy and alluvial soils o.
the coastal plain, wilt and root-kno
are most prevalent, while on the cla!
soils of the Piedmont plateau, the oc
currence of these diseases is rare
Estimate Of Damage.
Though it is difficult to form yer!
accurate estimate of the damag
! caused by these diseases, an estimate
based on a farm-tO-farm survey OF
typical county indicates that root-kno
of cotton alone causes a loss OF $50
q 600 600 n year. The loss Is Occaslone
/, not only by the death or dwarfing o
affected plants, but by the lowering o
the market value of infested land, b
the increased cost of cultivation 0
:, such land due to the growth of weed
where the cotton has died, and by TN
q fact that badly diseased fields mus
h often be used for crops less prontaDi
,bon cotton. This situation Is tn
more unfortunate because 1t Is for IN
most part unnecessary. These Oh
/, eases can be almost entirely controlle
nv the methods described in this pu
letin.
Tn times Of drought affected plant
are the first to show the lack OF wat'
| and may wilt slightly in the middle
| the day.
| When root-knot occurs with vii
| which is often the case, the symptom
| Of both diseases are present. III
| nlants usually all die or are so bad
| dvorfted that little or no cotton
| produced.
| Wilt is caused by fungus, a minu
| plant growth, which enters the roo
| from the soil. 1t grows vigorously
| tho water-carrying vessels of the roo
| and stems, causing them to turn blac
l. II shuts off wholly or in part the wat
| sunplv of the plant and eventual
| brings about the death of those bad
| affected. This fungus produces
| greot numbers several types of fru
| ing bodies, by which it is propagate
Closely related fungi of the sar
| genus cause serious willis or oKra' C
| feeweed, cowpea, tomato, watermei'
| potato and other plants.
| Wilt Spread by Numerous Agencies
II Wilt is spread by the direct grow
II of the fungus through the soil and
n any agency which will transfer spoI
II or disease-infected soil from one M
II to another. such as tools, the feet
II men or animals, wind and draino
i wafer. To prevent spread by drama
u wafer. terraces often may be built
n yantageously to turn the water II
II bitches. Stable manure and the CO
81 post heap may be infected by soil fr
q the feet of mules used in a diseas
field. and thus the wilt may be c
es ried to new areas, The disease Is OF
is spread most noticeably along freque
,ly " Travelled farm roads or paths. lie
- HnnGnAd EovvIe