The Colfax chronicle. [volume] (Colfax, Grant Parish, La.) 1877-1981, 1898-04-02
FARMER PLANTER.


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The two most common, weli-known
and destructive diseases of the cotton
plant are the so-called tired rust" and
s.blacl rust A third disease, also
very common, but less noticed, is some
times called yellow rust.
Both red and yellow rusts appear
early in the season, often before the
plants are half grown, but black rust
rarely appears until after the plants
have lowered. A long study of these
diseases as they appear in central
North Caroline has shown the writer
that both red and yellow rnsts are due
to unfavorable conditions Of the soil
and the weather never to parasitic
fungi :Black rust is always due to fun
gus closely related to that which pro-
duces early blight" or ''brown ring
spot" on leaves of Irish potato and
tomato plants u.s. 81
called physiological diseases. For
these the fungicidal sprays, found so
useful in orchard or garden, are of no
value. Although black rust is a fun
gous disease, the use of spray against
it is not recommended.
The fungus never attacks healthy
leaves, but only those which have been
injured by some other agent. Onthe
cotton plant black rust always follows
yellow or red rust on the same leaves,
and completes the destruction which
the others began. 50, if we can pre-
vent red and yellow rust, there will be
no damage from black rust.
Red and yellow rusts are caused
primarily by a lack of plant food and
of moisture in the soil. They are most
common and destructive upon old,
worn and dry soils which are lacking
in vegetable matter. Such soils are al
ways deficient in nitrogen and potash.
The diseases may also occur on better
soils during very dry and hot seasons,
and when the soil has been improperly
prepared or the cultivation is wrong.
Red and yellow rusts are nothing
more or less than the premature ripen-
{ ing ofthe leaves. When either mois-
ture or inorganic food is wanting, the
leaves dry up, their green coloring mat
ter, chlorophyl, changes by oxidation
into red or yellow scoloring mat
ter, consisting of carotin and
xanthophyl respectively. These latter
coloring matters, unlike chlorophyl,
have no power to break up the GORDON
| ic acid of the air or to elaborate the
crude sap sent into the leaf from the
root. The. leaf itself ceases to be
nourished ~or to nourish the plant.
The leaf withers and the plant starves
remains dwarfish and feeble, setting
none or few bolls This is where the
damage comes in. The remedy fol-
these two diseases is partly but MOI
wholly within the control of the cot
ton planter. 1t may be summarized a
follows:
/. Deep breaking and shallow after
cultivation of the soil, to enable 1t t.
absorb and retain moisture.
g. Liberal fertilization, especially il
the matter of nitrogen and potash.
3. The restoration of vegetable mat
ter-humus- worn soils by plowinl
in green crops or carting on stabl
manure.
"a A more judicious and moderat
use of phosphate fertilizer. Tn
power of acid phosphate to hasten tn
maturity of the crop is well known t
all cotton growers. But early crop
and small yield are an invariabl
sequence in cotton as we'll as vegetabl
tcrops
a. Old worn soils must have thei
humus restored by blowing in gree
crops or by putting on stable manure
The best form of concentrated nitro
genous fertilizer for cotton is cottol
seed meal. M
The best form of potash fertilizer
kainit.
The best form of phosphate is aci
phosphate.
II The following formula, originally SUI
/ gested by the director of the Mort
Carolina experiment station, has bee
widely used throughout thecotton bel
and on the average upland soil has
4 thousands of cases given admirable r
suits:
Cotton seed meal !. 800 to '40) lbs. per &C
Acid phosphate 40J to 500 lbs. per &C
Kainit. 49,. 400 to $40 lbs. per &c
NoTE-So Soils rich in vegetable matte
or which have had a crop of clover I
peas turned under, will require lie
cotton-seed meal. Soils very poor
vegetable matter should never recei'
more than 400 pounds per acre OF ac
phosphate. In no case should less thu
400 pounds of kainit be given e
pounds is not too much), if a maximu
crop is desired.
i For clover or pea crop use sar
formula. without cotton-seed mes
These crops donot need nitrogen. F
grain crop give 800 pounds cotton-se
J meal, 400 pounds acid phosphate a
500 to I, 600 pounds kainit Gerald N
earthly, Botanist n. @. Experiment 81