Where several juveniles enter near each other, galls may be large and do considerable damage to the root. As the eggs begin to hatch, the new juveniles enter other cotton roots, and the cycle is repeated. Crop damage is the result of mass action, and a single plant may support over a million individual nematodes by late season. Back To Top Symptoms and yield loss. Root-knot is the only nematode species on cotton that produces easily recognizable symptoms on roots.
Galls are visible to the unaided eye, particularly after mid-season.
Aboveground symptoms are usually not as obvious. Infected plants are stunted and may appear to be drought stressed. Many times plants also express nutrient deficiencies even though soil tests indicate adequate nutrient levels. Drought stress may enhance the effects of root-knot, but excessive irrigation probably will not improve performance of severely infected plants because of the damage caused to the root system by severe levels of infection. The effects of severe root-knot damage are usually most obvious in sandier spots within fields rather than fieldwide.