As a rule this is not good practice. It suggests spraying without knowing whether a pest problem will occur in spring. Research has shown that, often as not, natural controls may largely eliminate high fall populations. Thus, populations have dropped below damage levels the following spring, demonstrating no need for sprays. Therefore we recommend monitoring in early spring to justify treatment.
Crane fly damage to lawn.
The lighter area is damaged lawn. Multiply the number of crane fly larvae you find in each sample by 4. If this number exceeds 25 per square foot, and the turf is thin, consider a chemical control. Healthy lawns on which growers use best management practices have been known to have 40 larvae per square foot and not show any damage. Pull cores 1 to 2 inches deep and tear them apart to count larvae.