• Contact FCWP

  • Lander Office 307-332-1052
  • Lander Shop 307-332-3709
  • Riverton Office and Shop 307-856-2192
  • Dubois 307-240-0710
  • fcwp@wyoming.com

Designated and Declared Pests

Mosquito (Culex tarsalis)

Culex tarsalis is one of the species of mosquito that can carry and transmit West Nile virus. Because this species occurs in certain areas of Fremont County it is a County Declared Pest.

Fremont County Weed and Pest monitors mosquito populations from June to September, trapping tens of thousands of mosquitoes and testing them for West Nile virus.

Culex I.D.

West Nile virus is a mosquito-borne disease that can cause a potentially serious illness in humans and horses. It can even be fatal. The number of human illnesses from West Nile virus in Fremont County fluctuates from year to year and the severity of symptoms varies greatly.

FCWP sells larvicide and other mosquito controls. Many other good products are available in local home and hardware stores.

Spraying for mosquitoes is conducted by cities and tribes. Funding for the spray program comes from a Wyoming Department of Agriculture grant, participating municipalities and FCWP, which administers the grant.

The best way to avoid West Nile virus is to avoid getting bitten. Here are some tips from the CDC and WY Dept of Health:


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WNV data

Click here to view all of Fremont County Weed and Pestís mosquito collection and West Nile virus testing data for 2016 in an Excel spreadsheet.

Data from individual communities of Fremont County can be found by clicking on the tabs at the bottom of the spreadsheet, which also include data for Natrona and Hot Springs counties. The information includes the dates and locations mosquitoes were trapped, the total number of mosquitoes and the number of Culex species, and the results of WNV testing. Positive test results are displayed in red.

Statewide info

Click here to view a PDF of the Wyoming West Nile Virus Surveillance Summary for 2016 from the Wyoming Department of Health.

About Zika

The two species of mosquitoes that can carry and transmit Zika virus, Aedes aegypti and Aedes albopictus, have never been detected in Wyoming so it is highly unlikely someone would contract Zika virus from a mosquito bite in our state.