Recognize these giant flying insects around your porch lights at night? Although commonly mistaken for mosquitoes, they are crane flies and although the larvae can be a pest of turfgrass, particularly in the northeastern US, the adults are mostly a nuisance since they do not rely on blood meals to survive. Crane fly activity has increased substantially in the last week or two, which is about a month earlier than we observed crane fly flight in NC last year.
The crane fly is a long-legged, skinny-bodied insect that can attract a lot of attention due to its size. Larvae are approximately 2-3 inches long with no legs so they should not be easily distinguished from other caterpillar pest species. They will chew on roots and crowns and, as they get larger, start to come up to the turf surface at night to feed. Damage starts as general thinning of the turf and can progress to large, brown patches with heavy infestations. To check for crane larvae presence, apply two tablespoons of lemon-scented dish soap in a gallon of water to the damaged area and watch for several minutes for larvae to emerge. Damage is most noticeable in the spring and the late fall when the larvae are large and constantly feeding. Chemical application is usually not necessary as maintaining a healthy soil environment will encourage turf to outgrow any damage. If treatment is required, please refer to our current recommendations for Crane Fly Larvae control on Turffiles.