Fair Memories: Two Former Technicians Reflect on Work at MMCD
August 18, 2023
How MMCD Monitors and Treats Catch Basin to Reduce Mosquito-Borne Disease
August 28, 2023
Another dry year means mosquitoes are staying below the 10-year average by a significant amount.
As summer winds down the number of mosquitoes throughout the District continues to drop - this year even more than usual.
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.
One of the earliest signs of Fall is the gradual decline in the mosquito population in the Twin Cities as the amount of precipitation tends to decline and certain species that surge earlier in the summer - like cattail mosquitoes or Spring Aedes - have run their course. This year we are seeing even lower numbers than average for mid-August thanks to the lack of rain this summer. While a few storms last week helped alleviate some of the drought, we remain abnormally dry throughout most of the District.
According to MMCD assistant entomologist Dr. Scott Larson, "The average number of human-biting mosquitoes in our CO2 trap network was remarkably low, just 7.43 per trap. There were only 24 traps with 10 or more ‘human-biting’ mosquitoes! There were also 24 traps that captured 10 or more Anopheles mosquitoes. So, we’ve really hit a strange moment in time thanks to the consecutive years of drought."
Here are the mosquito trap counts from last Monday, August 14th:
Mosquitoes continue to test positive for West Nile virus, mostly from species that don't bite humans as often.
More mosquitoes collected have tested positive for West Nile virus over the past few weeks. According to MMCD Vector Ecologist Kirk Johnson on Friday, "Seventeen of 47 mosquito samples tested were positive for WNV. Two of the positive samples were from CO2 trap collections and 15 were from gravid traps. All of the positive samples were Cx. pipiens or combinations of Cx. pipiens and Cx. restuans."
Culex pipiens or Culex restuans primarily bite birds and rarely humans. Culex tarsalis is the species most likely to transmit WNV to humans in the District, and their numbers this year have been relatively low.
It is common to see a surge in Culex mosquitoes in the Fall, even in dry years because this species is less impacted by drought conditions and thrives in man-made habitats like waste tires and catch basins. However, this year there has been more positive West Nile virus tests than the past several years.
This is a good reminder that even when nuisance mosquitoes seem to be low, it's important to take precautions to avoid mosquito bites. Wear insect repellent and cover up during peak mosquito activity periods.
Stop by the MMCD State Fair Booth Starting Thursday!
Once again this year MMCD will have a booth at the Great Minnesota Get Together! We will be in the Dairy Building located near the intersection of Judson Ave. and Underwood St.
Stop by to see lots of great educational information including live mosquito larvae and microscopes, a close-up look of mosquito control activity in your neighborhood, and a kids table with coloring sheets, tattoos, and more!
