European Crane Fly

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European Crane Fly adults are hatching! We are getting reports that the annual hatching of the European Crane Fly adults is going on in the lawns in Seattle, Washington area.  Although they are harmless, they can cause some panic among people not familiar with the mass hatching of these bugs that resemble giant mosquitoes.  This is especially true when thousands of them congregate on the side of a house. European Crane Fly adult females mate and lay eggs in lawns within 24 hours after hatching and then die.  The eggs hatch into a worm-like larva often referred to as “leatherjackets.”  It is the larval stage that damage lawns from the late fall all the way into spring of the following year.  Their activity is influenced by the weather.  Generally, they remain underground during the day, but will surface to feed on grass plants on warm, moist nights.  Many consider them to be the “grub” of the Pacific Northwest, although they have been found causing damage throughout New York and other parts of the Northeast. Having a large population of adults on your property does not necessarily mean that your lawn will be infested with leatherjackets as they do have many natural predators.  If you have had a problem with them in the past, it may be a good idea to take corrective measures to prevent lawn damage next year.