Florida Agricultural Experiment Station


 Fig. 4.-Root-knot on the root system of a cotton plant infested with
 nematodes.

tible to nematodes and such crops should be planted until the
worms die out or are greatly reduced in numbers. To entirely
kill out an infestation even by the use of immune crops is very
difficult, since there are many weeds that may serve to carry the
worms over from year to year. The infestation can, however, be
reduced greatly by suitable rotations largely made up of immune
or resistant crops. Some of the more common crops that are not
susceptible to attack by root-knot are beggarweed, chufas, corn,
cowpeas (Brabham, Iron and Monetta varieties only), most
grasses, peanuts, rye, sorghum, velvet beans, winter oats and
Crotalaria. It has been found that there is considerable varia-
tion in the susceptibility of different varieties of cotton to nema-
'tode injury but as yet no definite recommendations can be made
in this regard.