Mosquito Control

Mosquito spraying is done on as needed basis. That determination is based on mosquito counts and/or requests by citizens. To report mosquito activity in your neighborhood, please call 361.777.4601.  

The chemicals must make contact with the mosquitoes to be effective, so spraying is scheduled in the early morning and late evening, when mosquitoes are most active. Normal spraying times begin at 4:00 a.m. and at 8:00 p.m. Wind and weather conditions affect the effectiveness of mosquito control efforts. If winds are too strong or in wet conditions, spraying is not effective and may be rescheduled. 

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 and information on the chemicals used for spraying below, as well. 

SCHEDULE (UPDATED february 9, 2021)

DATE ROUTE TIME REMARKS
February 9, 2021  1 - 4 PM Conducted larvicide surveillance and treatments
January 29, 2021  1 - 4 PM Conducted larvicide and mosquito counts - afternoon spraying targeting ditches, parks, and ROWs
January 14, 2021  1 - 4 PM Conducted larvicide surveillance and treatments
January 10, 2021   AM/PM Rain event
       
December 21, 2020  1 - 4 PM Conducting larvicide treatments and spot spraying in ditches
December 15, 2020     Conducted surveillance and mosquito counts
November 20, 2020     Conducted surveillance and mosquito counts
November 9, 2020    AM Conducted mosquito counts
November 6, 2020    AM/PM Conducted mosquito counts
October 28, 2020    AM Rain event
October 26, 2020   1 - 4  PM Conducted surveillance and larviciding
October 23, 2020   1 - 4  AM  Conducted mosquito counts
October 19, 2020   1 - 4  AM/PM Conducted surveillance and larviciding
October 16, 2020   1 - 4  AM Conducted mosquito counts
October 14, 2020   1 - 4  AM Conducted spot spraying
October 13, 2020   1 & 4  AM Scheduled spraying from 4 AM to 7 AM
October 12, 2020   2 & 3  PM Scheduled spraying from 8 PM to 11 PM
October 12, 2020   1 - 4  AM Conducted mosquito counts and larviciding
October 9, 2020   1 - 4  AM Conducted mosquito counts
October 7, 2020   1 - 4  AM Conducted mosquito counts
October 6, 2020   1 & 4  AM Scheduled spraying from 4 AM to 7 AM
October 5, 2020   2 & 3  PM Scheduled spraying from 8 PM to 11 PM
October 5, 2020   1 - 4  AM Conducted larviciding and mosquito counts
October 2, 2020   1 - 4  PM Conducting spot spraying
October 2, 2020   1 - 4  AM Conducted mosquito counts and spot spraying in alleys and ditches
October 1, 2020   1 - 4  PM Conducted mosquito counts in parks, alleys, and ditches
September 28, 2020   1 - 4  AM Conducted larviciding and mosquito counts
September 25, 2020   1 - 4  PM Conducted larviciding and mosquito counts
September 25, 2020   1 & 4  AM Scheduled spraying from 5 AM to 7 AM
September 24, 2020   2 & 3  PM Scheduled spraying from 8 PM to 10 PM
September 24, 2020   1 - 4  AM Conducted larviciding and mosquito counts
September 23, 2020   1 - 4  PM Scheduled spraying from 8 PM to 10 PM, targeting ditches and parks
September 23, 2020   1 - 4  AM/PM Conducted larviciding and mosquito counts
September 22, 2020   1 - 4  AM/PM Conducted surveillance and larviciding
September 21, 2020    AM/PM Rain event
September 19, 2020   1 - 4  AM Scheduled spraying from 4 AM to 7 AM
September 18, 2020   1 - 4  AM Performed scheduled spraying from 4 AM to 7 AM
September 17, 2020   1 - 4  PM Rain event
September 17, 2020   1 - 4  AM Conducted larviciding, mosquito counts, and day spraying
September 16, 2020   1 - 4  PM Scheduled spraying from 8 PM to 11 PM, weather pending
September 16, 2020   1 - 4  AM Larviciding and mosquito counts
September 15, 2020   1 - 4  AM/PM Larviciding and spraying in high count areas
September 14, 2020    PM Rain event
September 11, 2020   1 - 4  AM/PM Conducted larviciding and some spot spraying in high count areas
September 10, 2020    AM Rain event
September 9, 2020   1 - 4  AM/PM Conducting mosquito counts and day spraying
September 9, 2020    AM Rain event
September 8, 2020   1 - 4  AM/PM Conducted larviciding, mosquito counts, and some spot spraying
September 2, 2020   1 - 4  AM Larviciding and mosquito counts
September 1, 2020   1 - 4  AM Larviciding and mosquito counts
August 31, 2020   1 - 4  PM Larviciding and mosquito counts
August 28, 2020   1 - 4  PM Larviciding and mosquito counts
August 26, 2020   1 - 4  AM/PM Scheduled larviciding and mosquito counts
August 25, 2020   1 - 4  PM Larviciding and mosquito counts

Spraying Logs from Previous Months
- Mosquito Control Spraying Log - June 2020
- Mosquito Control Spraying Log - July 2020
- Mosquito Control Spraying Log - August 2020

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

The City uses two adulticides--Mosquitomist ONE ULV and Biomist 4+4 ULV.

Mosquitomist Safety Data         Biomist Safety Data