Fogging for Mosquitos

A significant component of the Mosquito Control program's operation involves adulticiding—more commonly referred to as "fogging." Our Ultra Low Volume (ULV) Fogging Program is an effective method to control populations of adult mosquitoes.

Routine Adult Mosquito Control

During mosquito season, the department will conduct routine ULV fogging in participating communities throughout the summer. Select your county below to see the fogging schedule for your community.

Unscheduled Fogging 

In addition to routine activities, we work closely with the Maryland Department of Health and local health departments in response to any concern of mosquito-borne illness. Once health officials determine a need for response, mosquito control personnel will survey the affected area to eliminate potential breeding zones and determine if there is a need for further treatment. 

If there are enough adult mosquitoes present in the area, personnel will use backpack sprayers to apply Talstar P Professional—a bifenthrin-based adulticide—onto foliage where mosquitoes rest in order to control adult mosquito populations. In certain cases, the state may determine a need for unscheduled truck-based ULV fogging in response to a public health concern. 

During a disease-related unscheduled fogging, any existing fog exemptions in the affected​ areas will be temporarily suspended.

Residents of Baltimore County can find information regarding fogging treatments on the press release page of the Maryland Department of Agriculture Maryland Department of Agriculture - Press Release Page. 

About The Pesticides & Equipment We Use

Learn about the types of pesticides used in truck-mounted and aerial fogging.​​

The department is very concerned about the effects of fog activities on non-target organisms, like honeybees and bats. Therefore, the department only conducts truck mounted fogging or misting at night as bees are not active at night. The droplets in the fog have an extremely small diameter. The surface to mass ratio of these droplets is such that these droplets do not leave residue on surfaces. Like tiny parachutes, when they are pulled down by gravity, drag keeps them from falling. When bees become active the next day and crawl across surfaces, those surfaces do not have any pesticide from our fog. The droplet size averages 15 micrometers. There are 1000 micrometers in a millimeter. Fog machines are tested, by law, twice a year.

Stay Informed About Fogging

In the event of an unscheduled fog, the department will issue public notice. All notices will be posted on the MDA website and on the Maryland Department of Agriculture Facebook page. 

For the latest updates on fogging, contact the Mosquito Fog Alert Hotline: 410-841-5870