History of the Leavenworth Mosquito Control District
Prior to the
formation of the Leavenworth Mosquito Control District the Lions Club of Leavenworth had undertaken over a number of years
to raise funds for the aerial spraying of mosquitoes in the Leavenworth area. This spraying typically occurred shortly
before the Fourth of July. However in the late 90's this practice began to be challenged and spraying was suspended
in 2000 and 2001. Mosquito numbers in 2002 were high enough that the City of Leavenworth combined with the Chamber of
Commerce took responsiblity for a final aerial spray prior to the formation of the Leavenworth Mosquito Control District.
Funding was provided by the Lions Club. In the meantime Lions Club members had begun the process of preparing the question
of a Mosquito Control District to be put to the voters along with funding for it through taxes.
In the Fall of
2002 voters overwhelmingly approved the formation of a Mosquito Control District and its funding. Since a board
and an approved budget had to be in place prior to the approval of tax collection, no taxes were available for 2003.
The Lions Club generously donated about $20,000 in funds which they had collected for mosquito control. This along with
a small loan obtained in late 2003 financed the initial season of operation. In 2004 through 2006 taxes were assessed
based on property value. In 2006 the state informed the district that to continue such an assessment a levy
must be approved each year. The board therefore decided to collect taxes on a per parcel basis.
After the District was approved by the voters the Chelan County Board of Commissioners
accepted applications for the initial Mosquito Control Board and appointed 4 board members: these were Tom Guthrie,
Dayle Massey, Karl Pflugrath and Bill Luebke. A fifth Veronica Harrison was appointed by the city. President Tom
Guthrie and Secretary Treasurer Dayle Massey were the original board officers. Dayle Massey is the only continuously
serving member from the original board. He now serves as the Board President. Tom Guthrie stepped down for a few years due
to illness. Other obligations or poor health resulted in the transition of the other 3 members. Bill Luebke was
the first to resign followed by Veronica Harrison and Karl Pflugrath. Becki Subido was the first new member. Later she
resigned. The city appointees have seen the most transition: Veronica Harrison was replaced by Ken Coffin who was in
turn replaced by Bob Kelly. When Bob Kelly resigned, county appointee Larry Meyer took his place and Tom Guthrie returned
to take Larry Meyer's place as a county appointee. When Tom Guthrie orriginally resigned Dayle Massey stepped up to become
president and Chester Marler joined the board to serve as Secretary Treasurer. Larry Meyer and Nick Stemm are regular board
members. All board members have served at least 5 years (at least 2.5 two year terms). People interested in serving
as board members are invited to contact Manager Jenny Mullins at 509-548-5904 and attend board meetings.
The board began meeting in early 2003 and soon became persuaded that the District
activities should include larvaciding. A number of Mosquito Control Districts were consulted. Manager Lorna Johnson
of the Curlew Mosquito Control District was especially helpful and agreed to provide some instruction and materials (forms
and applicatiors) for the new District.
The position of Manager was advertised and Manager Jenny Mullins was hired
to begin May 1st . She took the information which the Board had gathered and quickly obtained a permit and materials
(including the larvicides Bacillus thuringiensis and monomolecular film). She began the treatment of larval habitat
as she searched for such sites by soliciting information from the public as well as by scouting areas by truck and on foot.
Later in the summer Central Washington Helicopters provided a tour of the District and this resulted in the discovery of two
ponds and an untreated swimming pool. In later years, complaints have been used to eliminate backyard breeding
areas as well as to pinpoint new treatment sites.
concentrations of Aedes vexans in 2003 and 2006 resulted in aerial spraying of the adulticide malathion. In
2006 a concentration against the hillside east of East Leavenworth Road resulted in the spraying of 275 acres. In 2003
most of the district (except for the northern most end) was sprayed in late June. Complaints continued and the area
between Shore Street and the southern end of East Leavenworth Road was aerially sprayed again in late July following a ground
spray behind Alpine Heights in early July.
In 2004 Assistant David Wood was hired. He worked for us
from 2004 thru 2006. In 2007 Assistant Bruce Hill was hired and provided the majority of larvaciding assistance. In
2010 he retired and was replaced by Barry Moats who served through 2012 with additional help in the big snowpack years of
2011 and 2012. Arnica Briody took his place in 2013 and 2014. 2015 had such a low snowpack (like 2005) that no assistant was needed. In 2016 Teri Sessions joined the District as
an assistant: she has served continuously since then. These assistants
have been an integral part of our success over the years, since water levels in May and June result in a much greater area
of larval habitat. They each have their own pesticide applicators license and work independently in their assigned areas
using their own vehicle.
In 2004 the treatment of storm drain catch basins began. The introduction to the district
of an economical long lasting material Bacillus sphaericus helped to spread out the larvaciding work schedule.
Bacillus thuringiensis israelensis (Bti) continued to be the treatment of choice but in 2006 the use of methoprene
was also adopted. It became clear in 2006 that Bacillus sphaericus was not effective against Aedes vexans.
Fortunately this discovery was made while there was still enough time to retreat the areas with Bti.
levels in 2004, 2005 and 2015 (record lows in 2005 and 2015) combined with the knowledge of sites gathered in 2003 to produce
successful larvaciding years where no adulticiding was necessary. These years also had early high temperatures so that
larvaciding began by April 1st. In 2006 and 2007 larvaciding was not needed until late April, but more recently larviciding
has begun by early April. Although water levels were much higher in 2006 with flooding in the parks, control of
mosquitoes along the rivers was quite successful. The missed larva were due to high rains and runoff against the East
Leavenworth hillside. In 2008, 2011 and 2012 high snowpacks also led to high runoff but adequate control was achieved
In 2007 water levels were comparable
to that of 2003. Successful control was achieved. Almost all sites had trap counts below ten. However trap
numbers at Waterfront Park and the Wheeler Woodland climbed in August to over 20 and 30 Culex per night. The
approach of West Nile virus means that we cannot afford to become complacent. We seek to improve our control efforts
as long as mosquito-borne disease remains a serious threat to our community. In 2010 excellent control was achieved
with a high trap count of just 12 mosquitoes and fewer than 10 Culex per trap. These numbers were further reduced in
2013 with a high trap count of just 6 mosquitoes. In 2012 the numbers of Culex between Prowell and East Leavenworth
road were a source of concern, peaking at 39. 2014 saw high numbers of Aedes against the East Leavenworth hillside and
south of Shore Street while 2015 had high numbers of Culex by the Mine Pond snowmelt pond. We continue
to pay close attention to each area with regular trapping during the season. It is believed that Bti was bound up by
the organic matter at Mine Pond so Bacillus sphaericus (Bs) will be tried there from 2016 on starting in late June.
June 2016 the Prowell Road area once again has an elevated number of Culex mosquitoes. West Nile virus testing
on June 10 showed Ramp readings of 54 and 32 for Culex pipiens mosquitoes collected from two traps in the area. This
was the only time readings were over 10. RAMP testing was begun in 2014 since VecTest was no longer available.
was the first year we conducted aerial larviciding by helicopter. This was done on April 10 and May 2 to 20 acres against
the East Leavenworth hill side just east of 1.5 miles to 1.9 miles along the East Leavenworth Road. This snowmelt wetland
was the source of the adult mosquito problem in 2006 and was particularly large and deep this year (and much too brushy to
use a boat) . The same granules we spread by hand (Vectobac: Bti) was spread by helicopter. Very few adult mosquitoes
were found there over the summer so the aerial larviciding was successful.
2017 was a very good year for successful control of Culex mosquitoes. The previous
year there had been enough to test for West Nile virus at Prowell, Run of the River and the Wheeler woodland. In 2017
all these areas along with Mine Pond were treated with Vectomax (a Bti, Bs combo) by June or July since it provides better
control than Bti alone in wetlands with high organic matter. No more than 5 Culex were caught
at any location overnight so West Nile virus testing was not needed. This is similar to the degree of success achieved
in 2010 and 2013 when testing was also not needed. There were enough Aedes to generate a few complaints
in some areas especially Prowell where up to 32 were caught, but this was still well below the minimum of 70 required for
spraying of nuisance adult mosquitoes.
was also a very good year for successful control of Culex mosquitoes: no more than 8 Culex mosquitoes
were caught in a trap: this was the first time that West Nile virus testing was not required for two years in a row.
Very high water in May resulted in a more nuisance mosquitoes, but there were relatively few complaints.