Weekly Update – June 27th – Mosquitoes Remain Below Average, First West Nile Found
July 6, 2022
Weekly Update – July 11th – Mosquito Numbers Approach 2021 Levels, More West Nile Found
July 19, 2022
Adult mosquito totals were below average district-wide, but a few areas did see a surge at the beginning of July thanks in large part to cattail mosquitoes.
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 District maps that show numbers of adult mosquitoes collected in CO2 traps usually have a lot more red spots in early July than we saw with the most recent update from the MMCD entomology lab. Most traps that were set the evening of Tuesday, July 5th collected fewer than 300 mosquitoes with many collecting fewer than 50.
A few traps did collect a high number of mosquitoes including CO2 traps set in northern Washington County, northeastern Anoka County, and Carver County. The surge in these spots is due to high numbers of cattail mosquitoes (Coquillettidia perturbans), a species that emerges once per year right around the beginning of July. If you compare the two maps below, you can see the areas with the highest number of human-biting mosquitoes overall had a significant portion made up of cattail mosquitoes.
Here are the mosquito trap counts from last Tuesday, July 5th:
No new mosquitoes test positive for West Nile virus this week.
Last week we announced that we had our first positive result for West Nile virus from a pool of mosquitoes collected in Hennepin County on June 22nd. Since that time 47 new pools have been tested and none have been positive.
We are entering into the latter part of summer when mosquito-borne disease tends to increase and with the hot, dry conditions we have experienced in Minnesota the threat of West Nile virus remains present. Continue to take precautions by using insect repellent, wearing long sleeves and pants, and avoiding peak feeding times of dawn and dusk.
For the latest updates on mosquito control, disease activity, and planned treatments, follow MMCD on Twitter or Facebook.
