Whatcom Crane Fly Survey
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.
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
To learn more about how the survey is conducted, click
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
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.
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
- 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
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.
- 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
- Did you know that homeowners around the Puget Sound spent an
estimated $13 million on home use pesticides for crane fly control
- Did you know that Diazinon and Dursban, two commonly used insecticides
for crane fly problems, were found in rainwater going into Lake
- 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?