Nematode risk thresholds for cotton

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

<200*

200-500*

>500*
Sting

0

10

>10
Lesion

<100

100-250

>250
Stubby root

<100

100-250

>250
Lance (H. galeatus)

<200

200-500

>500
Columbia lance (H. columbus) not detected in Virginia
Reniform not detected in Virginia
 *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 cotton.

 pmphipps@vt.edu
  bkeeling@vt.edu