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Lake Whatcom Crane Fly Survey 

coming soon In Bellingham (WA), our drinking water supply comes from beautiful Lake Whatcom. Lake Whatcom has areas that have become developed and are now residential neighborhoods. Very small amounts of pesticides have been found in the storm water run-off around the lake and this has people concerned. Some of the pesticides include Dursban and Chlorpyrifos, common insecticides used for controlling crane flies in home lawns.

WSU Master Gardeners wanted to know really how bad are crane flies in Lake Whatcom, so in the spring of 2001, Whatcom County Master Gardeners surveyed 45 lawns in the Lake Whatcom watershed for crane fly infestations. They found no populations high enough to require any pest controls. Since 2001, over 300 lawns have been surveyed and still no crane fly problems.

To learn more about how the survey is conducted, click here.

Current Survey Results 

Our 2006 cranefly survey was expanded to include Lake Samish, Lake Whatcom watersheds and surrounding areas. The results have been tabulated and show NO crane fly problems in need of control measures.

In our survey this year, we also searched for another potential pest that has not yet been found in Washington State, the European Chafer. The larval stage of this beetle is also a pest of turf grass, eating roots just like crane fly larvae. Our volunteers surveyed over 60 homeowners' lawns, and NO traces of these white grubs were found either.

A warm thank you goes out to the Master Gardners and associated volunteers that worked on the survey this year, as well as the homeowners that enrolled to have their lawns surveyed.

Past Survey Results 

In 2004 and 2005, Master Gardeners surveyed almost 200 lawns collectively and NO crane fly problems were found either.

In 2002, after surveying 78 lawns, the Master Gardeners found:

  • 90% of Lake Whatcom Lawns had no crane fly larvae

  • 9% of Lake Whatcom Lawns had 1-5 crane fly larvae per square foot of turf

  • 1% of Lake Whatcom Lawns had 6-10 crane fly larvae

  • 0% of Lake Whatcom Lawns had 11 or more crane fly larvae

In 2001, after looking at 45 lawns, the Master Gardeners found:
  • 65% of Lake Whatcom Lawns had no crane fly larvae
  • 30% of Lake Whatcom Lawns had 1-10 crane fly larvae per square foot of turf

  • 0% of Lake Whatcom Lawns had 11-20 crane fly larvae
  • 5% of Lake Whatcom Lawns had 20-25 crane fly larvae
At the time of these surveys, no crane fly problems were found in Lake Whatcom. Insecticide treatment is not even a consideration until populations are over 25 larvae per square foot. Even then, there are many other options to consider that will manage crane fly problems. Pesticide applications for crane flies are probably unnecessary in many cases. This misuse of pesticides is wasteful, costly and can have detrimental effects to the environment, wildlife and ourselves.

Quick Facts 
  • Did you know that homeowners around the Puget Sound spent an estimated $13 million on home use pesticides for crane fly control in 1999?

  • Did you know that Diazinon and Dursban, two commonly used insecticides for crane fly problems, were found in rainwater going into Lake Whatcom?

  • Did you know that Diazinon and Dursban are currently or will be no longer available for home use on lawns?

  • Did you know that crane fly problems are not very common?

In this article:

Survey Background

Current Survey Results

Past Survey Results

Quick Facts

See also:

Survey Details

Survey Signup Info

Lake-Friendly Gardening Kit

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