Last updated: June 4, 2018
Mosquito Spraying: Public Health Protection
Mosquito-spraying services are undertaken by the Maryland Department of Agriculture where a positive test for a mosquito-borne disease is identified through surveillance activities. Residents are notified of the positive test result, the potential for the transmission of a mosquito-borne disease, and the immediate need for mosquito spraying services in a geographic area. For information on any unscheduled mosquito spraying, click here.
In addition to the surveillance work, local health officials monitor the occurrence of mosquito-borne cases in humans for West Nile virus (WNV), eastern equine encephalitis (EEE) virus, and St. Louis encephalitis (SLE). The cases are mapped using a geographic information system (GIS) and mosquito-spraying services are enhanced in the identified areas.
Exclusion requests: Properties requesting an exemption or exclusion from the mosquito-spraying program will not be recognized where mosquito-spraying is necessary to protect public health or where services are enhanced based on documented human cases of mosquito-borne diseases.
Mosquito Spraying: Nuisance Abatement
Mosquito-spraying services to abate or control adult mosquitoes as a nuisance are initiated only when surveillance data exceeds the action threshold. The action threshold to initiate mosquito-spraying services for nuisance abatement includes the following and applies only to participating communities:
Action threshold to initiate ground mosquito spraying activities:
- A minimum of 12 adult mosquitoes using the light trap collection method is required; or
- A minimum of 3 adult mosquitoes in a 2-minute period using the landing rate method* is required.
Action threshold to initiate aerial mosquito spraying activities is:
- A minimum of 100 female adult mosquitoes using the light trap collection method is required; or
- A minimum of 12 mosquitoes per minute using the landing rate method* is required.
*A count of the number of mosquitoes landing on an inspector’s body below the waist is used to determine the adult mosquito population.