The numbers of mosquitoes in the area is rising, but the population has been unusually low since the start of June and remains below historic levels.

Williston Vector Control reported unusually low mosquito counts for the first 3 weeks of June. River level and temperature changes have caused an increase in the mosquito population over the past 5 days, although numbers remain relatively low when compared to the same date in previous years. Williams County has graphs showing mosquito trap counts for the past at

Lower than usual population means a planned missing by the U.S. Air Force Reserve that was scheduled for this week was canceled.

Over more than 10 years, through the Department of Defense Innovative Readiness Training Program, U.S. Air Force Reserve planes and staff have deployed to North Dakota and conducted training missions that included aerial ULV spraying applications in the Williston area. Communities served through the IRT program provide the mosquito control products but the services, including staff salaries, flight time, fuel, etc, come at no cost to the community or the Vector Control District.

The USAF spray mission scheduled for the Williston area during the week of June 22-26 was prevented due to the low number of mosquitos in the region; USAF guidelines and vector control standards prevent treatment applications if the mosquito population is beneath established benchmarks.

Local vector control officials base insecticide application on population count and the incidence of disease in trap counts.

An extensive larviciding program is aimed at reducing the number of immature mosquitoes before they become adults that bite and can transmit disease. But due to the large flood plains near Williston, not all areas can be accessed and treated in the short 10-15 day development window it takes for mosquitoes larva to grow into full grown adults. Vector Control monitors for mosquitoes on a daily basis and strives to quickly respond to any outbreaks in mosquito populations.

Response to an outbreak includes the operation of four ground fogging Ultra Low Volume sprayers. These are truck mounted units that can be deployed quickly and precisely to manage adult mosquito outbreaks. Aerial applications of ULV spray is primarily contracted through a local aerial applicator that utilizes rotary or fixed wing aircraft.

Mosquitoes are a routine part of the Williston Basin ecosystem and very common during the summer months. Individuals are strongly encouraged to wear repellants which contain DEET, Picardin, or Lemon Eucalyptus. DEET is the most effective but Picardin is a good alternative. The entire body must be covered for repellents to be fully effective.

Notices of ground and aerial applications for the treatment of mosquito outbreaks will be posted on the Williams County Facebook page ( throughout the summer.

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