Adulticide Program

Adulticide Program

Visit the Route Maps tab on this websiteto see maps of the adulticide spray routes that the OCW follows.  Visit the Public Notice tab on this website for notifications about which route(s) will be sprayed on what date. To avoid killing beneficial insects (such as bees or butterflies) all truck mounted spraying operations are conducted after sunset and before sunrise.

To request that your property be sprayed to control adult mosquitos please call the OCW at 802-247-6779.  When submitting a service request, please be prepared to provide the following information to assist our technicians in responding to your request:

E-911 address
Contact telephone number(s)
Email address
Description of problem

If you wish to opt your property out of all spraying for control of adult mosquitos:

If a No Spray Zone request WAS NOT submitted for the preceding year and/or there have been changes in ownership, contact information, or property boundaries, a letter must be submitted listing the name(s) of the property owner(s), his/her/their contact telephone numbers, the E-911 address of the property, and include a property map which clearly shows the property boundaries along the public or private road(s). The OCW mailing address is: PO Box 188, Brandon, VT  05733.

If a No Spray Zone request WAS submitted for the preceding year AND there have been no changes in ownership, contact information, or property boundaries, an email to the OCW containing the E-911 address and requesting No Spray Zone status again for the current year will suffice. The OCW email address is:

No Spray Zone requests must be renewed annually before April 15th. Requests received after April 15th will be honored, but there could be a delay between receipt of the request and marking the property, which could result in the property being sprayed.

For further information about adulticiding activities or No Spray Zone requests please contact us at 802-247-6779.

The OCW considers several factors to determine where and when to spray. Each week during the “season” OCW employees place insect traps throughout the district.  Collected after being in place for 24 hours, the contents of each trap are analyzed to determine the number and species of mosquitoes collected.  Only when human-biting mosquitoes are present in a particular area in numbers greater than established thresholds will spraying be done.  As well, spraying can only be done under very narrow weather conditions: rain cannot be forecast, winds must be light, and the air temperature must be above 50 degrees.  Citizen service requests provide information about where the nuisance level may be high.

The OCW employs a team of pesticide applicators who must go through comprehensive training and then be licensed by the State of Vermont before they can spray.  We have a fleet of trucks mounted with specialized Ultra Low Volume spraying machines for control of flying adult mosquitoes; these are the trucks you may see fogging or hear driving through your neighborhood on summer evenings.  The OCW treats both public and private roadways.  The spray plume generally is 300 feet wide (150 feet either side of where the truck drives) but may extend further downwind.

Before the start of each season, the sprayers must be tested to ensure that they are properly calibrated and produce a fog that meets the (EPA-approved) pesticide manufacturer’s specifications for droplet size and spray rate.  The extremely small droplet aerosols used in adult mosquito control are designed to impact primarily adult mosquitoes that are on the wing at the time of the application.  Degradation of these small droplets is rapid, leaving little or no residue in the target area at ground level.  Our sprayers use small amounts of chemicals due to very fine atomization, and all chemicals are handled strictly according to the extensive laws and regulations that govern their use.

The EPA and the OCW want to remind citizens who are concerned about adulticide spraying, who are sensitive to chemicals, or who have respiratory problems, that they may take the following actions to help reduce exposure:

  • Stay indoors with the windows closed when your area is scheduled for spaying.
  • Cover outside items like furniture and grills while spraying is occurring. Bring pets, pet food dishes, and children’s toys indoors.
  • If you are outdoors during spraying operations and you can see the spray fog, try to avoid contact by moving at least 150 feet upwind of the fog plume. If you can’t avoid contact, rinse your skin and eyes with water as soon as possible.
  • Wash fruits and vegetables from your garden before storing, cooking, or eating.
  • If you think you have had a reaction to the mosquito spray, talk to your doctor or call the Poison Control Center at 1-800-222-1222.