Weekly Update – September 15th – Preparing for 2027
September 15, 2026
The mosquito season is essentially over for 2026.
The mosquito season is essentially over for 2026.
Last week was the last week of mosquito surveillance at MMCD for 2026 as temperatures this week will be too cold to allow for noticeable mosquito activity. When temperatures at dusk are below 55 degrees, mosquitoes are no longer capable of flight and we are anticipating temperatures at or below that tonight and next week. This means this is our LAST Weekly Buzz for 2026.
Just because cooler temperatures have set in doesn't mean we are completely done with mosquitoes this year. On fall days when there are warmer temperatures, a few mosquitoes will venture out, just like on those warm spring days. Several species in Minnesota overwinter as adults and may return when conditions are right with enough moisture and heat. However, the majority of floodwater mosquitoes have ceased their activity and their eggs are not likely to hatch until 2027.
Last week, when temperatures were still warm enough, only one trap collected 100 mosquitoes and most captured fewer than 10. Here are this week's maps:
West Nile Virus Risk Declines Again as Temperatures Drop
The Culex mosquitoes that spread West Nile virus need warm temperatures in order to survive and they won't be seeing that over the next two weeks. This week's Vector Index dropped and it is not likely to increase through the remainder of 2026:
Screenshot from a Beta version of the new Vector Index.
Winter Preparations at Mosquito Control
Last week we talked about the cattail mosquito season which has been underway this fall, tracking and preparing for mosquitoes that will emerge in 2027. Planned helicopter activity was postponed last week due to rain and instead will take place this week starting on Tuesday.
Throughout this winter there are several exciting projects happening at mosquito control including a lab renovation at the St. Paul office and a garage upgrade at the Maple Grove facility. More about these construction projects coming soon!
We also are going to be retooling our website and communications tools this winter to improve accessibility and bring a great, new look! Stay tuned!
Video of the Week - Cattail Season, Part 1
Seasonal Public Affairs Assistant Kylie Rich-Vetsch has been putting together the video version of the Weekly Buzz along with lots of other great content this summer. Last week she created a video to explain MMCD's cattail mosquito season. Part 1 shows the biology of the cattail mosquito. Part 2, coming this week, will show how MMCD responds.
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