Nematode risk thresholds for corn

A = nematodes are not likely to cause crop damage
B = borderline populations in which crop damage may occur if other factors stress the crop
C = populations are likely to cause crop damage and a significant loss of yield

 Risk code based on nematodes/500cc soil (August 1 to November 20 of year before planting crop)

Nematode	A (little or no risk)	B (moderate risk)	C (high risk)
Root knot	<500*	>500*	--
Sting	0	10	>10
Lesion	<200	200-490	>500
Ring	<200	200-700	>700
Stubby root	<20	20-200	>200
Lance	<100	100-300	>300

 * Applies only to fields planted to corn, milo, cotton, soybean and tobacco when samples were collected.  If peanut was planted, the nematode is not likely to pose any risk to corn.

 pmphipps@vt.edu
  bkeeling@vt.edu