Scout by walking a “W” pattern and picking 50 stems at random. Evaluate for pinhole-type or lacing-type feeding damage on the leaves on each stem.
Management threshold is reached if 40 percent or more of the collected stems show tip feeding.
Management may be achieved by harvesting early or following control recommended in UWEX publication A3646 “Pest Management in Wisconsin Field Crops.” Fields with high damage should be checked during regrowth for green-up. FG
—University of Wisconsin Integrated Pest and Crop Management website