The young crane flies like to hang out in soil, and these are the ones that you'll see munching on your lawn. Its the adults the you'll find buzzing around your outdoor lights.
You can ID the young ones - they are wormlike with tough brownish skin and are called "leatherjackets"; adults are about 1: long with wings and spindly legs, and look like giant mosquitoes
The baby crane flies are real villains. They attack both the roots and tops of grass blades in the spring. In mid-May, crane flies cease the attack and retreat to hideouts just below the soil, until August or September. When they emerge as adults, they look intimidating, resembling overgrown mosquitoes. However, adults won't attack your lawn. They only emerge for mating and egg laying. Beware as unusually warm weather in late winter or early sprig can lead to early feeding and as a result excess damage to lawns.
Here's what you need to do if you've got crane flies and need to get rid of them. First determine the health of your lawn. Healthy lawns can withstand well over 40 leatherjackets per square foot with no assistance. The action threshold for weak lawns is lower-about fifteen leatherjackets per square foot.
After May 15, the damage has been done. Focus on preventing damage next year by taking good care of your lawn, but don't bother killing this generation of crane fly.
-Making and keeping your lawn healthy is the most important thing you can do in the fight against crane fly.
-Disrupt crane fly habitat and promote a healthy root system by removing thatch every few years and increasing oxygen flow through aeration.
-As semi-aquatic creatures, leatherjackets love soggy lawns. Keep your lawn well drained or plant something else in waterlogged areas.
If you're lawn is filled with robins, starlings, parasitic nematodes and ground beetles search you're in luck. The guys love to eat crane flies. Avoid using pesticides that could poison your allies. By-the-way, 90-95% of chemical applications for crane fly are unnecessary! If you really need to get rid of the crane fly, you may decide to arm yourself with a chemical substance. Apply suitable chemicals between April 1 and 15. Be sure the chemical is legal for home use on lawns.
Find out if the pesticide you are using is deadly to bees or birds. Avoid harming innocent bystanders-birds are one of your biggest partners in the struggle against crane fly! If you are using a chemical toxic to bees, at least pull out any flowering weeds or clover they may visit later. Spray in the evening when bees aren't around. Definitely talk to your local tree service before you start to spray.