Weekly Update – August 29th – Successful State Fair as Mosquito Season Winds Down
September 7, 2022
Metropolitan Mosquito Control District 2022 Year in Review
December 21, 2022
In our last surveillance update of 2022 the mosquitoes are beginning to disappear for the season.
Every Monday night starting in mid-May through September, the Metropolitan Mosquito Control District sets out a variety of mosquito and black fly traps throughout the district and employs a network of sweep net collections done by employees and volunteers. Any insects collected are brought back to our lab on Tuesday to be identified throughout the week with maps published to show current mosquito and black fly activity.
The big story of 2022 was pretty similar to 2021 in terms of weather - it was dry. The second year of low precipitation totals meant that there were even fewer adult mosquitoes collected in the District in 2022 than in 2021 during most weeks. This is the time of year when regardless of precipitation, mosquitoes tend to enter diapause due to cold overnight temperatures. However, even for a week when the 10-year average is low the 2022 totals are below it.
According to MMCD assistant entomologist, Dr. Scott Larson, during the night of September 19th "it was a warm night and we collected a fair number of adult mosquitoes. Only 10 of the 138 CO2 traps did not trap any mosquitoes. Culex mosquitoes will soon start to prepare for the winter."
Here are the mosquito trap counts from last Monday, September 19th:
West Nile is still active, but risk decreases as temperatures cool down.
August and early September are the peak activity periods for West Nile virus, but so far the risk has stayed pretty low this year.
MMCD Vector Ecologist Kirk Johnson reported that there were several new pools of mosquitoes to test positive for West Nile virus from collections made in late August and early September including the first positive samples for specific traps in Anoka, Dakota, and Washington Counties. For the year, 42 of 617 samples tested were positive for WNV.
We will have more season wrap-up updates over the coming weeks, so stay tuned and let us know your mosquito questions by contacting us.
For the latest updates on mosquito control, disease activity, and planned treatments, follow MMCD on Twitter or Facebook.
