What is an identifying feature of armyworms?

Armyworms are known for their distinct behavior of feeding on turf and other plants in large groups or clusters. This gregarious feeding habit can lead to significant damage in a short period, particularly in lawns and agricultural fields. Armyworms often migrate and can rapidly deplete plant material, causing noticeable brown patches in grass or crop fields.

While some options may seem plausible, such as their color, which may vary and isn't a consistent identifying feature, or the misconception that they are only active in winter, the defining characteristic lies in their collective feeding behavior. The idea that they contribute positively to soil health is misleading, as they are primarily considered pests.

Therefore, the group feeding behavior is critical for identifying armyworms and understanding their impact on turf and crops, making it the correct answer.