Weekly Update – May 11th – Mosquito Surveillance Begins, Lyme Disease Awareness Month
May 11, 2026
Very few mosquitoes were collected on the first night of adult surveillance.
Overall numbers of mosquitoes were low in the first week of surveillance thanks to cool temperatures and dry conditions.
On Monday, May 13th we had our first round of adult surveillance where traps and sweep net collections were made and turned into the MMCD entomology lab for identification. Unsurprisingly, the overall number of human-biting mosquitoes was low.
According to MMCD Entomologist, Dr. Scott Larson, "most of the mosquitoes collected this week were Culiseta inornata, a species that overwinters as adults. These large mosquitoes will bite humans in the spring, but, at other times of the year are "rather reluctant to bite humans" as they are more interested in feeding on domestic animals." Most CO2 traps collected zero mosquitoes last week and very few sweep net collections added any. Only one trap collected more than 10 - one set near Victoria in Carver County that brought in 14.
While mosquitoes were absent, black flies are beginning to make an appearance, especially in the south metro. One trap in Cedar Lake Township collected 1,280 black flies last week and several others in southern Dakota, Scott, and Carver Counties collected over 100. Black flies emerge from moving water in rivers and streams and often peak in spring after water levels rise due to spring rain and snowmelt. Conditions have been dry in the Twin Cities so far this spring, but more black flies may still be on the way in coming weeks.
Here are this week's District Maps:
More Rain, Means More Treatments - Expect Helicopters This Week
Overnight several areas of the Twin Cities received over an inch of rain, which is enough to hatch another brood of mosquitoes. Field staff will be out today and tomorrow checking wetlands to see where mosquito larvae developed and the MMCD entomology lab will be determining which of those species are human-biting. Treatments via helicopter will likely begin on Wednesday of this week with a dual purpose:
- First round of treatments will target areas where larvae hatched after this week's rain.
- Second round will target wetlands where cattail mosquitoes are abundant
We are approaching the time of year when cattail mosquitoes have worked their way to the surface of the water and are preparing for the 2026 debut around the 4th of July. MMCD will do everything in our power to reduce the numbers of these aggressive, human-biting mosquitoes.
Last week MMCD staff were busy once again doing pre-hatch treatments and other work. Here are some of the numbers from last week, courtesy of MMCD Assistant Director Jon Peterson:
- Treated 5,560 acres by helicopter
- Treated 324 acres by drone
- Treated 200 sites by drone
- Inspected and/or treated 4,803 ground sites
- Treated 1,448 ground site acres
Tire Recycling Drop-Off Events are Underway!
For 2026 MMCD is offering free tire drop-off events for every county in the Twin Cities. For most counties there will be one event at the beginning of the season and one at the end. Residents can drop-off up to 10 tires per vehicle and must show proof of residency. More requirements are listed on the Tire Recycling page. Last week we held our first event of the year in Anoka County and this week we will be in Washington County.
Waste tires are a nuisance that can become habitat for dangerous vector species of mosquitoes like Aedes triseriatus, which is the primary vector of La Crosse encephalitis in Minnesota. Removing and recycling waste tires from outdoor spaces goes a long way in protecting public health in Minnesota.
See the dates for tire drop-off events in your county and sign up for an appointment today!
Get a Free Mosquito and Tick Safety Kit for Lyme Disease Awareness Month!
We are still in Lyme Disease Awareness Month and we want to make sure residents of the Twin Cities have everything they need to be protected. Last week we unveiled our new "Tick Magnets" and this week we have another new and exciting offering. For 2026, we are offering FREE Mosquito and Tick Safety kits to help you stay protected. These pouches will come stocked with Tick ID cards, Tick remover keys, repellent wipes, tips for protecting yourself from mosquitoes and ticks, and more!
More details will be coming later this week about how you can request one of these sweet new kits!
Win an MMCD T-Shirt!
Here is your chance to win either the new MMCD Attack Larvae T-Shirt or last year's Laser Loon shirt. Sign up for "The Weekly Buzz" newsletter with Weekly Mosquito updates. Each week there will be a trivia question at the end. Two correct answers each week will get a shirt!
Enter your e-mail address below to sign up now!
