Weekly Update – August 8th – At Least One More Week with Few Mosquitoes
August 15, 2022
Weekly Update – August 29th – Successful State Fair as Mosquito Season Winds Down
September 7, 2022
August rains led to a slight uptick in nuisance mosquitoes - emphasis on "slight."
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.
After a dry summer, rainfall and August has been close to normal, but we have yet to see a resulting increase in floodwater mosquitoes. Some of the heaviest rain fell during the week after the collection date of August 22nd so it's quite possible that the end of August and early September will see some of the highest numbers of adult mosquitoes we've had in weeks.
According to MMCD assistant entomologist, Dr. Scott Larson, "once again, there were no CO2 traps that collected more than 130 human-biting mosquitoes this week. But there were 5 that trapped more than 50 this time."
Here are the mosquito trap counts from last Monday, August 22nd:
Positive West Nile virus tests now up to 25 for the year.
New positive RAMP tests came back last week for mosquitoes collected in Hennepin County bringing the total for the year up to 25 pools that have tested positive. Counties with positive results include Anoka, Dakota, Hennepin, and Ramsey.
According to MMCD Vector Ecologist Kirk Johnson: "For the year the WNV infection rate in mosquitoes tested is similar to our experience at this point last year. The infection rate this year stands at 2.6/1000 mosquitoes tested, last year at this time it was 2.2/1000. There are some differences, however, between the two years that suggest we are currently in a position of risk to human health that is lower than at the same time last year. Last year we tested many more pools early in the season, before WNV was detected than this year. Had that not been the case, last year’s infection rate through this time of year would have been higher."
As evident in the maps above, MMCD gravid traps, which are designed to collect container breeding mosquitoes like the Culex species that vectors West Nile virus, have been collecting more than our CO2 traps lately. August is a month that usually has declining numbers of nuisance mosquitoes at the same time as increasing risk for West Nile virus.
If you need tips to reduce your risk of mosquito-borne disease (and mosquito annoyance in general) check out our Resident's Guide!
MMCD at the State Fair
Come see MMCD at the Minnesota State Fair now through Labor Day! We have a large booth in the Dairy Building featuring educational displays, interactive elements, and lots of fun handouts. You can even see some live mosquito larvae up close!
For the latest updates on mosquito control, disease activity, and planned treatments, follow MMCD on Twitter or Facebook.
