Illinois Field Crop Applicators Practice Test

What stage of the black cutworm is primarily harmful to crops?

1. The egg stage

2. The larval stage

3. The pupal stage

4. The adult stage

The correct answer is: The larval stage

The larval stage of the black cutworm is primarily harmful to crops because it is during this stage that the worms actively feed on plant tissues. After hatching from eggs, black cutworm larvae can cause significant damage to seedlings and young plants as they cut them off at or near the soil line, resulting in substantial crop loss. Their feeding behavior makes them particularly detrimental to crops in the early growth stages and can lead to stand reduction. In contrast, the egg stage does not pose any harm to crops as the pests are not feeding. Similarly, during the pupal stage, black cutworms are undergoing metamorphosis and are not actively feeding on plants. The adult stage, while capable of laying more eggs and thus perpetuating the cycle, does not directly damage crops either. Therefore, it is the larval stage that is of greatest concern for crop growers.