Which symptom indicates garden symphylans infestation in fields?

The symptom that indicates a garden symphylans infestation in fields is characterized by circular patches of no crop growth. Garden symphylans feed primarily on the roots of plants, and their activity can lead to localized areas where plants are unable to thrive. These patches appear as circular zones in which crops fail to grow or exhibit significant reduction in vigor, making them a distinct visual indicator of symphylan presence.

Unlike general wilting or dying plants, which can be attributed to a variety of pest and environmental factors, the specific pattern of stunted growth in circular formations suggests a concentrated feeding activity by garden symphylans. This symptom is particularly useful in diagnosing infestations, as it allows for targeted management strategies in affected areas, differentiating it from other possible plant stressors or diseases. In contrast, other symptoms, while indicative of plant stress, lack the specificity that circular patches of no crop growth provide in relation to symphylan activity.