Table 2. Root rating averages from check strips in producersą
first-year cornfields, 1999.
The root-rating system used was the Iowa State University 1 to 6 scale:
1‹no visible damage or only a few minor feeding scars; 2‹some roots with
feeding scars but none eaten off to within 1.5 inches of the plant;
3‹several roots eaten off to within 1.5 inches of the plant, but never the
equivalent of an entire node of roots destroyed; 4‹one node of roots
destroyed or the equivalent; 5‹two nodes of roots destroyed or the
equivalent; and 6‹three or more nodes of roots destroyed.