Mosquito Control

The primary objective of mosquito control is to decrease the risk of mosquito-borne human diseases and is accomplished by a surveillance and response plan. Control measures include public outreach and education, promoting personal protection and source reduction, trapping, testing, larviciding, and adulticiding (spraying). 

Mosquito spraying is scheduled in the early morning and late evening when mosquitoes are most active. Normal spraying times begin at 4:30 a.m. and at 8:30 p.m. The effectiveness of mosquito control efforts depends on the wind and weather and may be rescheduled. 

To report mosquito activity in your neighborhood, please call 361-777-4601.  

Please see the current spraying schedule below. Spraying schedules from previous months are posted below the current schedule. You can find the spraying route map (PDF) and information on the chemicals used for spraying below, as well. 

SCHEDULE (UPDATED September 20, 2023)

DATE ROUTE TIME REMARKS
9/19/2023 1 - 4 AM Larvicidal surveillance and mosquito counts
9/18/2023 1 - 4  AM/PM Larvicidal surveillance/treatments, mosquito trapping and counts
9/12/2023     Rain event
9/11/2023 1 - 4 AM/PM Larvicidal surveillance and mosquito counts
9/5/2023 1 - 4 AM/PM Larvicidal surveillance/treatments, mosquito trapping and counts
9/1/2023 1 - 4 AM Larvicidal surveillance and mosquito counts
8/31/2023 1 - 4 AM/PM Larvicidal surveillance and mosquito counts
8/30/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
8/29/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
8/28/2023 1 - 4  AM/PM Larvicidal surveillance/treatments, mosquito trapping and counts
8/25/2023 1 - 4 AM/PM Larvicidal surveillance/treatments
8/22/2023     Rain event
8/21/2023 1 - 4 AM Mosquito trapping and counts
8/14/2023 1 - 4 AM Mosquito trapping and counts
8/7/2023 1 - 4 AM Mosquito trapping and counts
7/31/2023 1 - 4 AM Mosquito trapping and counts
7/24/2023 1 - 4 AM Mosquito trapping and counts
7/10/2023 1 - 4 AM/PM Larvicidal surveillance and mosquito counts
7/3/2023 1 - 4 AM/PM Larvicidal surveillance and mosquito counts
6/26/2023 1 - 4 AM Larvicidal surveillance and mosquito counts
6/23/2023 1 - 4 AM/PM Larvicidal surveillance and mosquito counts
6/19/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
6/16/2023 1 - 4 PM High mosquito count areas, scheduled spraying from 7:30 p.m. - 10 p.m.
6/15/2023 1 - 4 PM High mosquito count areas, scheduled spraying from 7:30 p.m. - 10 p.m.
6/15/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
6/14/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
6/12/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
6/9/2023 1 - 4 AM/PM Larvicidal surveillance/treatments and mosquito counts
6/8/2023 1 - 4  AM/PM Larvicidal surveillance/treatments and mosquito counts
6/5/2023      Rain event

Map of Spraying Routes
Portland is separated into four areas for mosquito spraying.

VectorMap(4routes).jpg

The City currently uses two adulticide applications - ULV Mosquitomaster 412 and Biomist 4+4 ULV.