El Paso herald. (El Paso, Tex.) 1901-1931, 1915-05-13
ROOT KNOT CAN Be PREVENTED

plants OF the highly resistant crops
the most important are:
Resistant Crops.
Barley. Pearl millet.
BeEEar weed. Redtop
Brabham cowpca- Rye
Broom corn millet- Sorghum.
Corn. Timothy
Crab-Erass. Velvet bean
Iron coWpea Wheat
Peanut Winter oats.
IN general IL iii be found desirable
to include several of these crops in a
rotation in which a summer legume al
ternates with a winter grain. IN the
south where the nematodes are perhaps
the most harmful. the two most sue
cessfUl winter crops are winter rye and
winter oats The following rotation is
suggested as a practical one
in the majority of instances
In the fail sow winter rye so early
that IL can make a good growth Before
it is necessary to pillow the land Cor the
next crop In the spriIlS turn under the
rye as green manure and plant corn.
Later place cOwpeas of the Iron or
Brabham varieties. which are resistant
to root-knOt, in the drill between the
rows. The second fall sow winter grain.
preferably oats, and either allow il to
ripen or cut it for hay while green.
The grain should be followed with Iron
or Brabham coWpeas, harvested as hay.
If a third year rotation is desired-and
it is much safer to use it-winter grain
should be sOWed, allowed to ripen. and
followed with resistant cowpeas for
hay. Barley or wheat may be substi-
tuted for the oats and rye and, after
the first year, velvet beans and beEgar-
weeds broadcasted instead of cowpeas-
With such a rotation carefully carried
out, il Is possible to control the nema-
todes There are, however, so many
ways in which these can be reintro-
duced that in sections where they are
known TO be prevalent il is desirable 10
repeat the rotation every four or five
years. If this is done, it is well to plant
the most susceptible crops Immediately
after the field has been cleared and to
follow these with less susceptible ones
until il is time to apply the eXtermina-
tion rotation again.
Signs of Disease.
The presence OF root-knOt is not al
ways readily apparent. Badly infested
plants are dwarfed, wilt readily in hot,
dry weather, and are usually a paler
green than healthy ones. With less Sc
we're attacks. however, these symptoms
are not always noticeable and the re
duced yield is nOr 1nfrequenuy believed
by farmers TO be a normal one. Where
there is any reason to suspect The ex-
istence Of rOOt-knOt, however. the roots
should be examined, and in the ease OF
some tuberOus plants, like the potato,
the tubers should be opened and the
inside examined TO detect the layer Of
1lscolored tissue usually found just be-
meath the skin Of diseased plants
Carriers of Eoot-kn0t.
Tubers. nursery stock. and bulbs are
common agents for transporting the
In addition. however, this is frequently
done by running water. and by soil
which cliRgs TO farm implements, the
feet Of men, and the hOOfs Of animals.
In heavily infested districts. therefore.
the farmer must be on the lookout to
close all these avenues Of infection.
Seed potatoes should always be select [
"a from fields where a critical iuspec-
ton shows no evidence Of the disease.
ana no parts OF diseased roots should be
permitted TO be mixed in the manure
that is TO be placed on uninfested land. I
Greenhouse conditions are almost
IDEAL for the development of nematodes
The most efficient method of EXTERN ]
mating them is TO steam the soil by
passing steam into perforated pipes Z
laid al a depth of one foot below the I
surface Of the soil Where this is pos
d bic the infested soil must be removed. ]
lot WhiteWash, and then refilled with 4
'resh, clean soil Land that is flooded I
or a period of from two 10 six months
.ach yedr Is practically certain 10 be !
rec from the pest
Orchards also suffer frequently from /
OOl-knOL Unfortunately, however. the
radlcatlOn Of the disease here is more
lfrcult. since the determination IF the
lematOdes by a rotation of immune
llants is obviously impossible. Where I
'nly two or three trees are found TO be 4
they should be removed and /
destroyed, and the surrounding soil
reated with a solution Of formaldchyde /
It the rate Of about two or three gal
Ons per square yard. Occasionally a
avish use of fertilizers and thorough ]
cultivation Of the field Will aid the
lants 10 outEr0w the trouble. The only
eally safe way, however. is TO make
ertain that the land is not infested be-
ore the trees are planted and then to /
'e equally certain to use only unin-
70 H. al . eaHH 60 h n
he end 10 take the time, to free the
and from the pest than to have the
rees remain several years without any
ppreciable growth. as is too often the
ase where nematodes are abundant. 1t
S also most unwise to plant a very
uscepuble crop, such as melons. Gu
umbers, or tomatoes. in a field that is
o be turned into an orchard later.