Baltimore County is stepping up its efforts to combat the unprecedented levels of midges around its waterfront areas.

The county’s Department of Environmental Protection and Sustainability will double the area of its helicopter treatment in Back River, according to a department news release shared on social media by Baltimore County Councilman David Marks.

The treatment will now reach 2,400 acres of lower Back River in addition to the 1,200 acres of upper Back River that were already receiving it. The river is set to undergo its next treatment on Wednesday and conclude on Thursday, according to the news release.

Previously, the helicopter flew 45-foot passes across the river. Under the modified treatment, it will fly 90-foot-wide passes, but use the same quantity of Bacillus thuringiensis israelensis, also known as Bti. According to the department, Bti is a bacterium that naturally occurs in soils and targets midge, mosquito and black fly larvae. It is not harmful to people, fish, crabs or other aquatic invertebrates.

The current Back River treatment area costs $1.3 million per season and is being funded by the Maryland Department of Agriculture and Baltimore County. It’s one of a few programs worldwide that are treating this scale of midges, according to the news release.

Residents documented intolerable amounts of midges that swarmed on their cars, front doors and terraces, according to the Baltimore County Environmental Reporter, which allows residents to report midge issues.

Del. Robin Grammer, a Baltimore County Republican, said the midge issue is “unbelievably out of control” at a community briefing held by Marks on May 29.

“This problem is so bad. Imagine selling a house with midges all over the entire property, or having a birthday party or just stepping outside to enjoy your coffee in the morning,” Grammer said during the recorded Zoom briefing.

Though the insects are a significant nuisance, they are not known to bite or carry diseases, according to the county’s website.

The surge of midges can be attributed to an unusually cool spring, heavy rains and strong winds causing an influx of freshwater into tidal waters, the county reported. As a result, salinity levels in brackish water have severely declined, and the freshwater makes a perfect habitat for the midges to prosper.

Kevin Atticks, Maryland’s secretary of agriculture, said during the recent briefing that he wants to solve the midge problem long-term, but that “our focus right now is making it through the summer.”

Reducing outdoor lighting, using LED or yellow bulbs and closing your shades can all help curb the midge swarms.

Hannah Epstein contributed to this article.

Have a news tip? Contact Irit Skulnik at iskulnik@baltsun.com or on X as @irit_skulnik