The European crane fly is an invasive lawn pest that is prevalent in the northwest as well as the northeast. While native species of crane flies live on decaying leaves, this species attacks pastures and lawns. The adults are harmless, but the larvae can damage your lawn. The larvae of the European crane fly are also known as leather jackets.
Control Crane Flies in the Lawn
When you see them, you think you're on the set of a B-movie - something like The Attack of the Giant Mosquitoes. After all, that's what European crane flies look like. The adults are harmless. It's the larvae that do all the damage. Sometimes called leather jackets, these larvae hatch in the fall and live on grass blades until they go underground for the winter. In the spring, they're back out on the lawn. They're very tough on that new grass you just planted.
How to Tell if You Have European Crane Fly Larvae in Your Lawn
Your lawn's appearance gives them away. In the fall and spring, look for patches of damaged grass. These patches may grow together and spread. Where the infestation is heavy, you may see a brownish paste. Dig into your soil and look for brownish-grey larvae about 1 inch long. A few are no problem. If you see lots - say, 80 per square foot - you should control them.
Let Nature Control the Adults
The adults are a feast for birds. Sparrows and robins just love them and can do a lot to control future populations.
Controlling the Larvae
You want to control European Crane Fly larvae when they're most active - usually in early to mid-April. Use Ortho® Bug-B-Gon® Insect Killer for Lawns. Be sure to follow the instructions on the label.