The news & observer. [volume] (Raleigh, N.C.) 1894-current, 1903-11-06
BLACK ROT OF The CABBAGE.
Experiment Station Bulletin on Cause and
Treatment of tbs Disease.

The North Carolina Agricultural Expert
mental Station has issued the following
bulletin on Black Rot of the cabbage:
For more than fifteen years there has
existed in North Carolina a very serious
disease of cabbage and other crops OF the
cabbage family The annual damage in
this State from this disease is probably
more than $4,000 Besides cabbage upon
which it most frequently operates this di-
sease attacks turnips, kale, Caufflowers,
mustard, rape, and in fact all crops and
weeds of the cabbage tribe.
The disease In cabbage is characterized
by the outermost leaves of the plants,
near the edges, turning first yellow, then
brown and finally black. The disease
spreads downward into the main stem ana
through this into the inner leaves OF the
head. While no plant of the cabbage kind
is wholly exempt. those of a loose or
spreading habit ike the collard are less
damaged than those which form close
heads, like the fat Dutch type. The di-
sease is very contagious, spreading from
plant to plant in the field. Frequently
large patches of cabbage apparently
healthy one day are found soft and rot
ten the next The disease is always most
virulent in hot, moist weather.
Cause of the Disease. Black rot OF the
cabbage and other plants of the same fam
lily, is caused by a germ or mlcrobe. Bacll-
lus campestris. This germ lives from year
to yeai. in the soil, attacking with increas
ing virulence successive crops OF the cab
bage kind, until at length it becomes prac-
tically impossible to grow these crops ex-
cept upon fresh or virgin soil. The germ
increases rapidly only during the warmer
months of the year, or while the temper
ature is above so +.
Treatment The treatment for Black rot
must be preventive. Spraying Is OF no
value in this case. Rotation of crops so
that no crop of the cabbage family shall
come upon the same field oftener than
once in three or four years is the first and
most essential precaution. The seed bed
should be made upon fresh ground each
year, or the bed should be burned over as
is done for tobacco beds, to kill possible
germs in the soil. Cabbage, turnlp and all
other crops Of this family should be grown
only during the cooler months, or while
the temperature is below so T. Ii only
few scattered plants in field show the char
acteristic yeliowing or blackening OF the
leaves. such plants should be pulled up
and burned. Do not throw diseased cab
bage leaves or plants upon the manure
pile The germ can live for an indefinite
period in the manure, and will be scat
tered over the feds with the manure. In
cultivating a field which contains diseased
cabbage or other plants of this family, be
fore going into another field clean all tools
carefully and thoroughly to avoid carrying
the germs into fields as yet free from
them Wage a vigorous war against shep-
herds purse, pepper grass, and all othef
weeds of the cabbage family, as these may
serve to propagate the disease during
wears in which other crops occupy the
land.
Excent as stated above no particular
variety of cabbage is exempt and no spe-
cial brand of seed will ensure freedom
from the pest.
GERALD MCCARTHY, Biologist
NJ c. Department Agriculture.