European crane fly (Tipula paludosa)

What do they look like?

Those huge mosquitoes you see from time to time might look like a jumbo bloodsucking pest, but they'd rather enjoy your lawn than you. Adult crane flies, which do look like giant mosquitoes, often exceed 1 inch in length. The larvae are also about 1 inch long, with an olive to greenish brown color. They curl into tiny balls when disturbed.

How do we know we've got them?

The real culprits are the larvae, so crane fly damage comes mainly in the spring. Take adults flying in the fall as a sign of potential damage next spring. The larvae love to feed at night or on dark cloudy days, especially in wet soils that have lots of thatch. If you see lots of tiny, greenish balls in your soil, the battle is on.

How do they damage our lawns?

The damage occurs to all cool-season grasses, although Perennial ryegrass sometimes escapes the crane fly's fancy. Their calling cards are dead patches, which emerge as the larvae feed on plant parts. They tunnel to the surface at night, which hurts immature plants.

How do we get rid of them?

The European crane fly thrives in wet, thatchy lawns, so core cultivation and vertical mowing minimize their favorite conditions. Products containing the nematode Steinernema carpocapsae can provide good control, but apply any insecticide after the first signs in the spring to prevent further damage.