Spring planting is just a few weeks away and the thought of cutworms in seedling corn will cross many a farmer's mind.

The dingy cutworm and the black cutworm are two of the most common species that attack corn in Iowa. Correct identification of these two species is critical because the black cutworm can cause significant cutting of small corn plants while the dingy cutworm rarely cuts plants. Occasionally a dingy cutworm will turn destructive and cut a plant, but this is not a common occurrence. Both species, however, will feed on leaves and chew up the edges.

These differences in feeding behavior makes it imperative that cutworms be correctly identified. If dingy cutworms are wrongly identified as black cutworms, this can lead to an expensive insecticide application to protect young corn plants that don~t need protecting.

Leaf-feeding on seedling plants is usually the first clue that cutworms are in a field. Good field scouting will detect leaf- feeding from black cutworms before actual cutting occurs. Unfortunately, there is no way to tell the difference between dingy cutworm and black cutworm leaf-feeding. You must collect the larvae and examine them with a hand lens or magnifying glass.

Both cutworms have four black tubercles (or warts) located on each body segment, along the top of their backs. The tubercles are usually the largest and easiest to see on the middle segments of the body. The black cutworm has the front pair of tubercles about half the diameter of the back pair. The dingy cutworm has both pair of tubercles approximately equal in diameter. The black cutworm skin is very grainy in appearance, similar to sandpaper.

Remember, correct identification of a problem is always the first step in arriving at an integrated pest management solution.