PRESS RELEASE: Mosquito Control activity is underway for 2025!
April 15, 2025
Mosquito Control day at the capitol took place earlier this month.
The first week of adult mosquito and black fly surveillance shows we are off to a slow start, but incoming rain is likely to change that.
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.
On Monday, May 12th MMCD staff set out around 200 adult mosquito traps for 2025 to get the first glimpse of what the spring looks like in terms of populations. Despite some warmer temperatures in April and May, conditions have been relatively dry, which is probably why adult mosquito numbers have been low. Lack of significant snowmelt and low spring rainfall totals contributed to fewer adult mosquitoes than average.
According to MMCD Entomologist, Dr. Scott Larson, "We averaged 12.5 human-biting mosquitoes per CO2 trap. The 10-year average is 24.0 for the same week of the year. In general, spring Aedes were the majority of mosquitoes collected. A small number of Aedes vexans were collected in certain locations last week but expect to see a lot of them next week after all the rain this week."
We start the year below average for total number of adult mosquitoes.
The last part of Dr. Larson's sentence is probably the most notable - as of this posting on the afternoon of May 20th, the Twin Cities has received over an inch of rain with more expected over the next 24 hours. That will likely cause some mosquito eggs to hatch and lead to more larvae which would emerge from the water next week. The update from last night's surveillance will likely show another low number, especially with traps being impacted by rain, but expect them to begin ticking up the week after that.
While mosquito numbers are low, black flies have been surging in certain areas along rivers and streams. Southeast Scott County had the highest number of black flies with over 2,000 collected in a trap in Cedar Lake Township. Other traps along the Minnesota and Vermillion Rivers collected over 100 and may see an increase over the next week.
Surveillance maps for the week of May 13th, 2025 can be found below:
Mosquitoes collected in CO2 traps on May 13th, 2025
Black flies collected in CO2 traps on May 13th, 2025
First Mosquitoes test positive for West Nile virus - much earlier than usual.
The first positive sample for West Nile virus is usually not found until much later in the summer - late June or early July is the typical time period with activity increasing in late summer. However, MMCD Vector Ecologist Dr. Jordan Mandli reports that the first sample was already found in a pool of mosquitoes collected during the very first week of surveillance. This positive sample was collected on May 14th in a Gravid Trap in Ramsey County.
Due to the timing of the collection, Dr. Mandli believes that it was likely an overwintering Culex mosquito that had the virus at the end of last year and re-emerged in 2025. That is more likely than a mosquito having picked up the disease already in 2025, though more testing will be needed and MMCD will look to testing in future weeks to determine the risk. Residents should take typical precautions against mosquitoes including wearing bug spray and avoiding the outdoors during their peak activity periods.
Helicopters will likely be active over Memorial Day weekend.
Due to the timing and quantity of this week's rain, it is likely that field staff will be seeking out larval habitat throughout the remainder of the week and treating based on the areas that are over threshold. This means that helicopters will likely be active on Saturday and potentially Sunday to get larval control materials in the water when they are the most effective.
The list of cities that have planned treatments will be posted each day on the MMCD website. Follow us on social media and subscribe to e-mail updates for the latest information about planned treatments.
May is Lyme Disease Awareness month! Be tick safe.
The month of May is Lyme Disease Awareness month and this time of year is when the risk of tick-borne Lyme disease is at its highest. Deer tick nymphs are actively questing and this stage in a tick's life cycle is when they are particularly dangerous because their small size allows them to attach to a host for longer and have a greater chance to transmit the pathogens that lead to disease. Be tick safe by checking yourself, your kids, and your pets any time you are near woods or long grasses and wear tick-repellent clothing.
Check out our post about Lyme Disease Awareness Month in May!
MMCD's Expanding Drone Program in the News
One of the exciting updates for 2025 is that every facility in the District will now have a treatment drone as part of its operations. This was mentioned in our season kick-off press release and several local news stations reported stories on how MMCD will use drones this year to help in the fight against mosquitoes.
Check out the story from KARE 11 below and other stories from North Metro TV and CTN Coon Rapids.
