Weekly Update – May 28th – Mosquitoes, Black Flies Continue to Surge Amidst Heavy Rain
June 4, 2024
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June 17, 2024
For the first time this year we have dipped below the 10-year average.
Mosquito numbers declined slightly on average but hot spots remain in Anoka and Carver Counties.
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.
For the first time in 2024 mosquitoes have dipped below the 10-year average after abundant collections throughout May. This follows the trend of the past several years where mosquitoes peaked in late May or early June and then declined through the rest of the year due to drought conditions. This year we are not experiencing drought, but so far we are following a similar pattern. Despite a slight decrease in the average number of mosquitoes collected, there are still hot spots in Carver County, a few locations in eastern Anoka County, and near the rivers close to St. Paul.
According to MMCD assistant entomologist Dr. Scott Larson, "On average, each within-the-District CO2 trap captured ~233 adult female mosquitoes. In general, most of the mosquitoes collected were Ae. cinereus, but some sweepers continue to collect spring Aedes mosquitoes. A few sweepers collected Culex species in their sweeps and Culex mosquitoes are widespread at the moment. Typically, we control for Aedes mosquitoes in the air sites and the control of Culex is added benefit. This season, for some reason (but I’ll blame years of drought), widespread and heavy rains haven’t resulted in our ‘normal’ broods of Aedes."
Black flies remain abundant in the typical hot spots along rivers and streams with one CO2 trap near Hastings collecting over 12,000 black flies. Treatments will continue when it is safe for staff to access rivers as the waters recede.
Here are the mosquito trap counts from last Monday, June 3rd:
The female lone star tick is identifiable by the single white dot in the center of its back.
MMCD's first lone star tick of 2024 was found in Hennepin County.
The lone star tick is rare in Minnesota and more abundant in southern climates, but several of these ticks are usually found each year in MMCD tick surveillance. Our first of 2024 was found last week in Hennepin County during a tick drag.
This tick is capable of transmitting the pathogens that can lead to several diseases and is also responsible for alpha gal syndrome - a condition that makes the host allergic to mammal meat (beef, pork, lamb, etc.). Be on the lookout for the lone star tick or the more common deer ticks when you are out in wooded or brushy areas this year!
The tick-risk meter is currently set to "Medium" and we are entering an increased time of year for nymph tick activity.
Recently CBS Minnesota posted a story about the mosquito hot spots in the Twin Cities. Check it out below:
