alternatives to pesticides - bugs/pests - crane fly larvae (european)
Actual size: Larvae 1” – 1 1/2”
European crane fly is a recent arrival in Washington and looks much like the variety commonly found here. Adult crane flies look like giant mosquitoes, and are sometimes called mosquito hawks or mosquito eaters. The common variety is harmless and usually found around marsh areas. Crane fly larvae or grubs are worm-like insects up to 1 1/2” long that live in the soil and destroy grass roots, crowns and shoots, leaving brown patches in the lawn.
Crane flies are attracted to soggy areas of your lawn, so minimize watering and/or improve drainage. Begin monitoring for larvae in early spring. Shorten the grass in one square-foot patches in several places around your yard. Pour warm water mixed with a little soap (not detergent) on the patch and count the grubs that emerge. If levels are above 25 grubs per square foot, treatment may be appropriate. Consult with the WSU Cooperative Extension Office for treatment options. A warm, dry fall may reduce the number of larvae because of their sensitivity to dryness.
Aerator Shoes - Research in Colorado has shown that aerator shoes that strap onto your feet can be used to control grubs. The long spikes on the bottom of the aerator shoes pierce the grubs as you walk over the infected sod.
Thatching or Aerating - Also, thatching or aerating the lawn can reduce populations.
Do these treatments on a cool, moist day when grubs are at the surface. More than 100 species of birds are known to feed on crane fly larvae. Crane fly larvae are among starlings’ favorite foods.
Nematodes - Beneficial nematodes are effective when applied to the sod according to package directions. Use it once soil temperature rises above 55 degrees, usually in late spring, when the crane fly is in its larval stage.