Weekly Update – July 18th – Drought Conditions Continue and Mosquitoes Numbers Stay Low
July 26, 2022
Weekly Update – August 1st – Nuisance Mosquitoes Stay Low, West Nile Positives Increase
August 8, 2022
Mosquito numbers are mirroring the totals in the drought year of 2021.
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.
The continued lack of widespread precipitation means that mosquito numbers remain lower than the 10-year average as we head into the last month of summer. The weekly averages collected in CO2 traps for 2022 remains almost completely in sync with 2021, a year with unprecedented drought and low mosquito activity.
According to MMCD assistant entomologist, Dr. Scott Larson, "Mosquito numbers are way down from the ‘normal’ average. Almost 10 times fewer mosquitoes than average (8.63 times if you want to get technical). There were only 5 traps with more than 130 human-biting mosquitoes."
Here are the mosquito trap counts from last Monday, July 25th:
More mosquitoes test positive for West Nile virus in Ramsey County.
There is another way that 2022 is a lot like 2021: the presence of West Nile virus. Two more samples of mosquitoes tested positive for West Nile virus this week, both collected from traps in Ramsey County. So far this year mosquitoes have tested positive in collections from Ramsey, Hennepin, Anoka, and Dakota counties.
According to MMCD Vector Ecologist Kirk Johnson, "Results this year are keeping pace with WNV test results from last year. This year 6 of 328 samples (1.83%) have tested positive. Last year through the same week of surveillance, 8 of 457 samples (1.75%) had tested positive."
Johnson says that the main factor that will determine the amplification of West Nile virus for the coming weeks is temperature and the forecasted highs of 90 degrees will likely mean more virus cases will be found. Residents are advised to take precautions by applying insect repellant, wearing long sleeves and light colors, and avoiding the peak feeding times of dawn and dusk.
For the latest updates on mosquito control, disease activity, and planned treatments, follow MMCD on Twitter or Facebook.
