Dam the mosquitoes...full steam ahead: Garrison Dam Mosquito Management Project, Williston, ND

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Dam the mosquitoes...full steam ahead: Garrison Dam Mosquito Management Project, Williston, ND. Major Mark Breidenbaugh Major Karl Haagsma Lt Col Don Teig Air Force Aerial Spray Unit. Operational Mission Locations. Historical mosquito problem. - PowerPoint PPT Presentation


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Dam the mosquitoes...full steam ahead: Garrison Dam MosquitoManagement Project, Williston, ND Major Mark BreidenbaughMajor Karl HaagsmaLt Col Don TeigAir Force Aerial Spray Unit


United States Air Force ReserveFly, Fight and WinI n t e g r i t y - S e r v i c e - E x c e l l e n c e

Operational Mission Locations2

To train for this tasking we are engaged in ongoing pest management programs on federal installations throughout the US. For example, we do mosquito and biting midge control on various installations along the Atlantic coast. Langley AFB in VA to Homestead AFB in FL. We also engaged in invasive weed control for habitat restoration and fire suppression and have a partnership with the coast guard to apply dispersants on oil spills. Recently we were approached by the Army Corps of engineers to do mosquito control on their property near Williston ND. We were treating 2 other bases in ND and explored this option as well.23Historical mosquito problemDuring the Corps of Discovery, Lewis & Clark encountered mosquitoes near Williston in August 1806

Clark left Lewis a note:Game scarce, mosquitoes troublesomeSo mosquitoes have a history in Williston. When Lewis and Clark visited the area during their Corps of Discovery adventure they reported troublesome mosquitoes.

With a population of about 12,500, Williston is located near the states northwest corner. Its also near the confluence of the Yellowstone and Missouri rivers, and at the upper end of the Lake Sakakawea reservoir, the third-largest man-made lake in the country. A third river, the Little Muddy, borders the citys east side.Its the wetlands these rivers create near the city that cause an almost unbearable mosquito problem. Not a new problem Lewis and Clark mentioned the hordes of mosquitoes they encountered in the area during their Corps of Discovery trek 200 years ago. In 2008, light-trap counts in the range of 24,000 adults each night arent unusual. Near Williston, the Missouri floodplain is four to five miles wide. When the snowmelt arrives late in the spring, it yields a tremendous hatch of Aedes vexans, which are aggressive mammalian feeders. Were not talking just swatting at mosquitoes its more about inhaling or ingesting them every time you take a breath. These folks are mowing lawn during the summer in their winter clothing with headnets. The local Wall Mart has, for all appearances, a religious shrine to DEET, when they can keep it stocked. People run from the vehicles to get in doors as if there was a down pour. Their actions during this blitz is often referred to as the Williston dance.


Williston, ND 4The mosquito problem in Williston is a function of the tremendous amount of habitat formed as a result of the confluence of the Missouri, Yellowstone, and little muddy rivers. The Yellowstone is undammed and the constant fluctuation of water levels assure asynchronous hatching of primarily Aedes vexans beginning in late May. Later in the season, Cx tarsalis show up and the situation moves beyond the nuisance level and into vector concerns.

Solutions arent simple. Because the floodplain is managed by the Army Corps of Engineers, adulticiding is not permitted. The area involved some 80,000 acres in all makes it too large for conventional aerial applications. Also, fluctuating river levels cause frequent new hatches, creating a continuous flush of insects. But for 2009, a remedy became available.trol. Williston is the 9th largest city in ND. With 14,000 residents.4Reported WNV Disease Cases in Humans,United States, 1999-2009*Reported as of 12/31/2009Year# Cases

# Fatalities19996272000212200166920024,15628420039,86226420042,53910020053,00011920064,26917720073,63012420081,356442009*6632216 %5 %6 %For the Dakotas3 %This a serious situation when we consider that the Dakotas as a whole have been disproportionally affected# of cases include Encephalitis/Meningitis/Fever/Other Clinical/UnspecifiedPercent of the total US numbers for WNV are shown for the Dakotas, the 2 states combined have 42,000 mg/kg)Registered for mosquito control Sept 2008 (Zenivex)Registration was supported by DWFP grantZenivexE20 aerial label, requiresconformational data for US EPA

I n t e g r i t y - S e r v i c e - E x c e l l e n c eIve provided a bit of background infoBut we are here to discuss our efforts with etofenproxNaled LD50 263Pyrethroids are metabolized extensively by mammals and quickly excretedIt is highly active against insects presumably because of a alkene-linked analog MTI-800

11MethodsPre-spray sampling:NJ light trapsLanding rates

Monitored droplet depositionUsed field-collected mosquitoes for caged bioassays

I n t e g r i t y - S e r v i c e - E x c e l l e n c eNJ light traps were part of the Williston Vector Control districts normal surveillance data.Ive said it before but a few of our landing rate samples were insane. You literally did not want to step out of the car.12Williston mosquito adulticide 20 July 2009Application parameters:230 mph ground speed150ft above ground level8005 flat fan nozzles (10)2000 ft swath width (1 swath offset)0.32 oz/acre (0.0035 lbs AI)began 1.5 hrs prior to sunset24,000 acres treated

Winds:280/5-8 knots, ground290/12-18 knots, altitude

Wind directionWilliston area spray block

I n t e g r i t y - S e r v i c e - E x c e l l e n c eWe made a single application this year and worked under reasonable environmental conditions. Our wind speeds were a bit high at altitude but we did have the benefit of a consistent wind direction throughout the application.13ResultsField-collected mosquitoes were: Ae. vexans 96% Ae. dorsalis 3%

Percent mortality of caged mosquitoes- corrected with Abbotts formulaI n t e g r i t y - S e r v i c e - E x c e l l e n c eSo first the good news. We did a good job on the caged mosquitoes. This is a good start because if you cant hit the target when they are standing still how can you get it when it is moving. Brother-in-law was a control site. 14Results

Landing rate countsI n t e g r i t y - S e r v i c e - E x c e l l e n c eThese show the results approximately 2 hrs after the application on the 20th. The yellow boxes on the map are locations where there was either a NJ trap or landing rates counts were performed. The Brother-in-law site was a control and there were no drops on the slides at this location.

I want to underscore how ridiculously awful the mosquitoes were The skunk hollow site was well outside the spray block (over 1mile) and we had good control there as it well, with plenty of droplets on the microscope slides 15ResultsAe. vexans collected in NJ trapsSprayindividualsI n t e g r i t y - S e r v i c e - E x c e l l e n c eI combined trap data from all locations inside the spray blocks to show that we had a significant depression in the vexans population for a few days. While this was considered noticeable and laudable by the populace, it seemed unacceptable to me. And like McArthur leaving the Philippines I felt, in spirit anyway, that I will return.16ConclusionsZenivex was a easy to work with material: noncorrosive and flushed with BVA oilLow toxicity makes it appealingEffective at mid-level rate in high mosquito density environmentPrice?

I n t e g r i t y - S e r v i c e - E x c e l l e n c e17Future plansStrategies for increasing the period of mosquito relief include:

Increase surveillance and scouting to determine larval development sites and larvicide these areasIncrease adult surveillance to determine optimum application timeIncreasing the size of the spray area to create a buffer zone around WillistonConsider applications on Army Corps landMultiple applicationsBegin at dusk for adulticide spraysI n t e g r i t y - S e r v i c e - E x c e l l e n c eAcknowledgementsJeff Keller, Army Corps of EngineersFran Bosch, Steve Kemp & staff, Williston Vector ControlStephanie Whitman, Valent BioSciencesBill Reynolds & Dean Gaiser, Central Life SciencesVicki Johnson, Minot AFBKarl Haagsma & Don Teig, AF Spray FlightAir Force Spray Flight aircrews & maintenance personnel

I n t e g r i t y - S e r v i c e - E x c e l l e n c ePre and Post treatment samples of mosquito larvae in single standard dip samples at Skunk Hollow (N486.486,W10340.746) pre-spray (31 May) and post-spray (1 June)

Skunk Hollow123456% difference

Location 1

Location 2pre126056240160105.6


- 99%



- 94%

no spray area728868128464.8


+ 9%

Sheet119-July20-JulyBrotherinlaw850Walmart40Ol' Police St502Bermuda500Skunk Hollow508




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