Our service is now known as Mosquito and Forest Pest Management to reflect our full range of services. 
Spray Schedule
The following spray blocks are scheduled to be sprayed this evening:
The following spray blocks were sprayed last season:
​Date Spray Block​
​July 11, 2014 ​2204, 2205, 2206
​July 28, 2014 ​1407A, 1411, 1414A, 1511, 1512, 2105, 2106
​July 30, 3014 ​1614, 2202, 2204
​July 31, 2014 ​909, 1611, 1609
August 13, 2014​ ​1614, 2202, 2208, 2210, 2211, 2220
​August 14, 2014 404A, 408, 710, 906, 907
​August 15, 2014 903, 904, 1407, 1409
​August 19, 2014 909, 1511, 1512, 2105, 2106, 2205, 2206, 2207
​August 21, 2014 1609, 1611
August 28, 2014​ 404A, 404B, 701, 710, ​2220
Spray Block Number
To find your spray block number, click here.
Telephone Hotline
To hear recorded updates, call 703-PWC-INFO (703-792-4636), then press '4', then '3'. This hotline is updated weekdays after 4 p.m. during the spray season.
The Prince William County Mosquito & Forest Pest Management Branch typically sprays for adult mosquitoes Monday through Friday throughout the mosquito season, and spray (adulticide) is often done at night. There is no set schedule or order in which the blocks are sprayed. Rather, there are criteria established by the branch that trigger mosquito spray in a given area or neighborhood.
One trigger that could result in mosquito spray is based on surveillance trapping of adult mosquitoes. If a threshold number of female mosquitoes is met or exceeded on a given night, this can trigger mosquito spray for that trap area. Another trigger for mosquito spray is that the mosquitoes caught in a trap area test positive for West Nile Virus.
mosquito trapmosquito trap
The ideal or most efficient form of mosquito control includes treating or larviciding immature mosquitoes in standing water.
Larviciding immature mosquitoes
Adult mosquito spray is limited in its affect on adult mosquitoes. The spray only affects adult mosquitoes that are out flying and come into contact with the spray at the moment it is being sprayed. The spray does not affect mosquitoes that are not active, at rest at night, or do not come into contact with the spray.
Mosquito Spray Truck Mosquito Spray Truck 
One of the most numerous and problematic mosquito species in Prince William County is not affected by spray, since it is inactive, or at rest during the evening and nighttime hours. That species is the Asian Tiger Mosquito. This species is among several found in the County that breeds in artificial or man-made containers, and is extremely difficult to control. You can help eliminate Asian Tiger Mosquitoes by making sure containers that hold a tablespoon or more of water are emptied or flushed out at least once a week.
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