Crane Fly

What it looks like

Crane flies are large flying insects that are sometimes mistaken for big mosquitoes. Unlike mosquitoes, adult crane flies don't bite or spread disease, and they're no threat to people. Their larvae, called leatherjackets, are the problem.

A leatherjacket, the crane fly larva that damages lawns. The picture at the top is an adult crane fly.

Adult crane flies come out in late summer, mate, and lay eggs within a day or so. The eggs hatch into leatherjackets, which feed underground in the fall, spend the winter in the soil, and feed again in spring. They change into pupae in the soil in mid spring.

Damage

Leatherjackets feed mainly on the roots and crowns of grass and other plants, causing stunted growth and brown grass. A healthy lawn can usually handle a moderate number of them, but if there are too many they can quickly do serious damage.

How nematodes help

The beneficial nematodes in BioLogic's products hunt down and kill leatherjackets in the soil. Scanmask stops the larvae from doing more damage and keeps them from growing into adults and reproducing.

How to apply

Treat with Scanmask (Ecomask also works). Focus on moist areas of the lawn and any areas that show damage.

Treating in the fall is ideal. The nematodes kill the larvae in the soil before they can damage the lawn in spring, and you'll have fewer new crane flies the following year. You can also treat in early spring, when Scanmask is the better choice because Ecomask needs warmer soil (about 68°F). One application typically lasts about a year, and often longer. Treat again when you see signs of leatherjackets coming back.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.