The Fayette falcon. (Somerville, Tenn.) 190?-current, 1915-07-23
WILT AND ROOT KNOT
Disease Attacks Many Plants
Besides Cotton.
May Sc Carried From One Field to
Another BY Various Agencies
Weeds Attacked by Nematode
Should Be Eradlcated.


OF Agricultural
Plants diseased with cotton root.
knot are distinctly stunted, but not ap.
preciably deformed, as in wilt, and
have peculiar sickly acknowledgment
color on both leaves and stems. In
times Of drought affected plants are
the first to show the lack OF water
and may wilt slightly in the middle
OF the day. II such a plant is dug up
carefully, the root win be found to be
covered with swellings or gals from
the size of pinhead to one-half inch
or more in diameter II one OF these
knots is broken open, numerous pearly
white, rounded bodies about one-half
the size OF a pinhead-the female ne
matodes-can often be seen with the
naked eye.
Cotton root-knot not only causes
great damage in itself, but when 1t is
combined with cotton wilt, as is fire.
quently the case, it greatly increases
the loss from wilt.
Root-knot of cotton and other crops
is caused by these minute eelworns,
or nematodes, which bore into the
roots and live there. The irritation
of their presence causes the formation
OF swellings or gals. The male worms
are too small to be seen with the
naked eye, but the females when full
OF eggs assume a spherical shape and
may often be distinguished In freshly
broken roots as described above. Each
female lays several hundred eggs, and
thus the worms are propagated.
Root-knot may be carried from one
field to another by any agency which
will transfer some of the nematodes or
their eggs, just as wilt Is disseminate
ed by means of the fungus that causes
the wilt disease. Drainage water is
perhaps one of the most important
means of spreading root-knot. Nurs-
cry stock also is a common agency for
the introduction of the nematode into
new territory Seeding pecans.
peaches, figs. mulberries or pome-
granates, and young asparagus, cab
bage, eggplant, strawberry, tobacco.
and tomato plants from infested sec
tions may carry the worms in their
roots or in the soil adhering to them.
In the West, where the nematode oc-
ours quite commonly in certain sec
tions on the potato, the worms are
carried In the tubers.
Root-knot Attacks Many other Farm
Crops.
Unlike witt root-knot attacks a very
large number of plants, many of which
are important farm crops. These sub
ject to root.knot injury may be divided
into two groups, according to their de-
gree Of susceptibility. The crops most
severely attacked by root.knot are as
follows: Soy bean, beet, cantaloupe,
carrot, celery, bur clover, crimson
clover, all varieties OF cowpeas Eek
cept Iron and Brabham and other Iron
hybrids), cucumber. eggplant. fg, let
tuce, okra, peach, pecan, pomegranate,
potato, satisfy. squash, tobacco, toma-
to and watermelon.
Plants less severely injured by
root-knot are the following: Alfalfa,
asparagus, bean, lima; bean, snap;
cabbage, clover. sweet; collard, cot
ton, mulberry, onion. pea, garden; po-
tato. sweet; radish. spinach, straw
berry, sugar cane, vetch. common;
vetch. hairy
few common weeds are subject to
nematode injury, and should therefore
be eradicated where the attempt is be-
ing made to reduce root-knot In fields
The most severely injured are the bal
loon vine, the maypop or passion flow
err. and the papaya or melon pawpaw.
Weeds less severely affected by root.
knot are mayweed. purslane and sweet
fennel
Such varieties OF cowpeas as the
Nhippoorwill. Clay, Black, Unknown.
Red Ripper, New Era, and others are
so susceptible to root-knot that not
only are they seriously injured, but
the growing Of them on nematode-in-
tested ields greatly increases the
number OF worms in the soil, and con-
sequently the damage to subsequent
cotton or other susceptible crops. II
Is a common complaint of farmers in
wilt sections that the wilt Is noticea-
bly, more severe after a crop OF cow
peas OF variety which is susceptible
to root-knot This Is due to the fact
that the nematodes make points OF en-
trance for the wilt fungus, which then
kills or further Injuries the plants.
There are few varieties of cowpeas
which are highly resistant to nema-
todes, including the Iron and the Brab-
ham and other Iron hybrids. These
should be the only cowpeas planted on
land infested with root-knot.
Control Measures for Root-knot
The rotation and diversiication Of
crops are OF fundamental Importance
to southern agriculture everywhere
and become absolutely necessary
where the root-knot nematode is pres
ent The principles on which such 70
tations are based are "a the use OF
crops immune 70 nematode attacks
until the nematodes are sufficiently re-
duced so that susceptible crops may
be proitably grown; and t2l the Grad
ioation OF all weeds subject to root