Managing lawn and turf insects: generalist feeders
Ants (Family Formicidae, Order Hymenoptera)
Ants are to be expected in lawns. Some ants nest in thin areas of the lawn. These are small ants, which make small mounds approximately 3 inches in diameter. Their preference for nesting in areas of sparse vegetation can lead to the assumption that the ants are causing the poor lawn development. This is not true. Ants do not feed on turf and so pose no threat to lawns. Control is not justified on the basis of protecting the lawn. However, another ant, the field ant, can nest in areas of the lawn which are growing well. These ants can build raised mounds of more than a foot in diameter. These large, high mounds can harm the grass and interfere with the lawn mower. Control of these individual mounds may be desired (see Extension bulletin FO-1066 for more information on ants).
Night crawlers (Phylum Annelida: earthworms)
Night crawlers are beneficial as they provide natural aeration of the soils and should be tolerated whenever possible. However, large populations can cause lumpiness and, in extreme cases, reduce the value of the turf for recreation. Vertical mowing can help reduce the lumpiness and also the amount of food available for night crawler development. Vertical mowing is best done in late summer, mid-August through September. Do not do vertical mowing in hot weather as it causes stress to the lawn.