Baltimore County Partners with State to Reduce Midge Pollution

Baltimore County recently announced a joint effort with the Maryland Department of Agriculture to reduce nuisance midge population on the Back River. 

logo of the Maryland Department of Agriculture

Baltimore County officials will soon be undertaking a joint effort with the Maryland Department of Agriculture to reduce the nuisance midge population on Back River. From early April through the fall of 2022, the Baltimore County Department of Environmental Protection and Sustainability (DEPS) will conduct aerial midge suppression treatments on a 1200-acre section of upper Back River.

According to the press release:

“We are committed to ensuring those who visit, live and work along Baltimore County’s waterways are able to enjoy our amazing outdoor activities,” said Baltimore County Executive Johnny Olszewski. “We are grateful for our partnership with Secretary Bartenfelder and the Department of Agriculture, in which we are establishing a long-term solution for suppressing this challenge in a safe and efficient manner.”

The County and state will split the $825,000 annual cost to apply a non-toxic Bti-based larvacide from a helicopter five to six times this spring and summer with the goal of reducing the midge population to tolerable levels.

Bti (Bacillus thuringiensis israelensis) is a naturally occurring bacteria found in soil, and is only harmful to certain organisms, specifically midge, black fly and mosquito larvae, and a few other aquatic flies. Research shows that it does not harm people, fish, crabs, or other aquatic invertebrates. It specifically targets midge larvae at particular times in their life cycles.

Trained, certified technicians from the County’s contractor, Helicopter Applicators Inc., following all applicable regulations and industry best practices, will spray a Bti-based naturally-occurring bacterial larvacide from a low-flying helicopter, during daylight hours, actively avoiding boaters and human activity in and around the water. More information about Bti is available on the Maryland Department of Agriculture (MDA) website.

Midges are small non-biting aquatic flies that often swarm near water or marshy areas where they breed. In recent years, people have observed an increased prevalence of these swarming insects, which create a significant nuisance for homeowners, boaters, businesses, and recreational activities.

Read the full press release. 

Read more about Bti.