I have noticed a large number of craneflies in my yard (turf) over the past...

Asked October 14, 2020, 1:50 PM EDT

I have noticed a large number of craneflies in my yard (turf) over the past week or so. Should I be concerned about the larvae that are to come? If so, what insecticide would be appropriate and when should I apply? Thanks for your time.

Franklin County Ohio

1 Response

Thanks for using Ask a Master Gardener with your Crane Fly question.

You are not alone in noticing the emergence of crane flies in your turf. There was an article published this week in the Buckeye Yard and Garden onLine (BYGL) concerning this very topic.
While the numbers may be concerning, there is no treatment required for our native Crane Fly larvae. They feed on decaying organic matter in the soil. That many times is in the form of thatch accumulation in our turf. The Crane Fly larvae, known as Leatherjackets, do a very important job for us in removing that accumulation.

There are non-native crane flies that were introduced a couple of decades ago from Europe and their larvae do feed on the crowns and blades of the turf. The non-native adults have a white stripe on the wings. That is how you determine if there is a necessity for any treatment.

Here is the link for the BYGL article:

https://bygl.osu.edu/index.php/node/1707

There is uncertain information as to how wide spread the European species might be.
If you determine that you are infested with European Crane Fly, the correct chemical for control would contain chlorantraniliprole, carbaryl or clothianidin. That should be applied yet this month. Here is a fact sheet from Michigan State University on the insect:

https://www.canr.msu.edu/ipm/diseases/cranefly

Hope this helps you out in determining any treatment. Thanks for your question.