NMCAW: Meet Mike and Pablo from MMCD’s Rosemount Facility
June 23, 2023
Weekly Update – June 26th – Drought Impacts Nuisance Mosquitoes; More Test Positive for West Nile
July 5, 2023
Mosquito numbers are declining as we head into the end of June and early July.
Dry weather continues to lower adult mosquito numbers. Weekend rain could contribute to slight rebound.
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.
2023 seems poised to go the way of 2022 and 2021 where adult mosquitoes peaked in spring and declined throughout the remainder of the summer. After several weeks of above average adult mosquitoes, we have now seen two consecutive weeks of declining numbers. Lack of rain over the past few weeks is one factor that has contributed to lower mosquito numbers as much of Minnesota has been abnormally dry for the third consecutive year.
According to MMCD assistant entomologist Dr. Scott Larson, "In brief, mosquitoes overall are down. Some species seem pretty happy though with decent numbers of Culex species and Aedes triseriatus around the District."
The Twin Cities saw the first significant rainfall in a while over the weekend with many areas receiving more than an inch of precipitation. This triggered a hatch of mosquito eggs in many wetlands and District field staff are out this week responding to the brood.
Here are the mosquito trap counts from last Tuesday, June 20th:
Mosquito-borne disease risk increases throughout the summer.
The risk of mosquito-borne disease tends to increase as we head into mid- and late-summer as the mosquitoes that vector diseases like West Nile virus and La Crosse encephalitis become more active. Hot weather can increase their activity and the past two weeks have seen warm, dry conditions.
There were no new positive samples of West Nile virus in adult mosquitoes tested this week. However, in neighboring Wisconsin a horse tested positive for West Nile virus in Dunn County, which is close to the Minnesota border.
Ensure you are protecting yourself from mosquito-borne disease by using bug spray, wearing long, light, and loose clothing, and avoiding the peak feeding times of dawn and dusk.
