The St. Charles herald. [volume] (Hahnville, La.) 1873-1993, 1917-12-22

ePrepared by the United States Depart
| ment of Agricultural
| Root-knot of cotton and other crops
is caused by minute eelworms, or nema-
| todes, which bore into the roots ana
| live there. The irritation of their pres
ence results In the formation of irregu-
| lar swellings, or gals, varying in size
! from tiny engagements on the small
roots TO knots an inch or more In ula-
meter on the large ones. The male
worms are too small TO be seen with
the naked eye, but the females when
| full of eggs assume spherical shape
| and may often be distinguished in
| freshly-broken roots as glistenlng
pearly bodies half the size of small
pinhead. Each female may lay several
hundred eggs, and thus the worms are
propagated.
How Root-knot Is Spread.
Root-knot may be carried from one
field TO another by any agency which
will transfer some Of the nematodes or
their eggs, in exactly the same manner
:hat wilt is disseminated. Drainage
water Is perhaps one of the most i'm
pOrtant means of spreading rOOt-knot.
In addition, common agency for the
introduction Of the nematOde into new
territory Is nursery stock. Seeding
pecans, peaches, figs, mulberries, or
pomegranates, and young asparagus,
cabbage. eggplant, strawberry, tobacco
and tomato plants purchased from in
Tested sections may carry the worms in
their roots or in the soil adhering to
tode occurs quite commonly on the po-
tato, the worms are carried in the
tubers.
Sandy Soils Most Subject to Root
Knot.
Root-knot is essentially a disease of
fight soils. Although the disease may
occur on heavier soils than wilt, yet It
Is not, as q rule, serious on soils con-
tanning large proportion of clay. In
general, the lighter the soil the more
severe the root-knot injury. The places
Of greatest damage are usually light
sandy spots or ridges in infected fields.
In gardens which have been highly fer
tilted with stable manure root-knot ia
often very severe.
Root-knot Attacks Many Farm Crops.
Unlike wilt, root-knot attacks a very
large number of plants, many Of which
are important farm crops. Those sinh
ject TO root-knot injury may be dj-
vided into two groups, according to
their degree of susceptibility. Some of
the crops most severely attacked bv
root-knof ere as follows:
Bean, soy Eggplant
Bean, lima Fig
Beet Lettuce
Cantaloupe Okra
Carrot Peach
Celery Pecan
Glover our Pomegranate
Glover, crimson Potato
Cowpea Gall varfe- Satisfy
ties except Iron. Squash
Brabham and Mo- Tobacco
netta) Tomato
Cucumber Watermelon
Plants less severely injured by root
knot are the following:
Alfalfa Pea, garden
Asparagus Potato. sweet
Bean. snap Radish
Cabbage Spinach
Glover. sweet Strawberry
Collard Sugar cane
Cotton Vetch, common
Mulberry Vetch, hairy.
Onion
A few common weeds are subject TO
nematode injury and should therefore
be eradicated where the attempt fs be-
ing made to reduce root-knot in fields,
The most severely injured are the bal
loon vine, the maypop or passion flow
er, and the papaya or melon pawpaw,
Weeds less severely affected by root
knot are mayweed, purslane and sweet
fennel
Some Farm Crops Resistant to Root.
Knot.
Fortunately, few farm crops are
largely or entirely immune to root
knot. BY employing these in suitable
rotations, nematodes may BIO starved
az, fnPsufo5 Go1Jc So bot s,,,,oa.