Weekly Update – July 6th – Have We Reached the Mosquito Peak?

The number of mosquitoes you are seeing likely depends on where you are.

The overall average number of mosquitoes collected per trap inched closer to the 10-year average last week, but the number of mosquitoes you encounter will likely depend on where you are located. The more highly populated urban and suburban areas stayed below the 10-year average pretty significantly while the more rural areas saw plenty of mosquitoes. Most of the mosquitoes captured were cattail mosquitoes, which come from cattail marshes that are more common in less developed areas.

Last week may have been the mosquito peak for 2026. Typically, the last week of June or first week of July coincides with the emergence of cattail mosquitoes which are abundant, but only emerge once per year. There were plenty of cattail mosquitoes in last week's traps and MMCD Entomologist Scott Larson says it seems likely that it was the peak we will see this year. We won't know for certain until we begin counting this week's traps, however.

Another species of concern was abundant in traps, according to Larson: "There were lots of Aedes triseriatus collected in our adult samples this week. There were over 50 in a single gravid trap this week.  As a reminder [triseriatus] are tree hole mosquitoes that can transmit a virus that causes La Crosse Encephalitis (LCE) in humans. This is a terrible illness that mostly only impacts children and can cause seizures, coma, paralysis, and permanent brain damage." MMCD will be ramping up surveillance for this species and doing what we can to mitigate their expansion and reduce the risk for LCE.

Here are this week's maps: