Frequently Asked Questions

Mosquito Control FAQs

What breed or species are these mosquitoes? They seem more aggressive this season.

The mosquitoes we are seeing currently are storm-water mosquitos. They are very aggressive due to their short lifecycle. These mosquitoes only live for a few days. They spend these days looking for a blood meal and laying eggs. They need the blood meal for the protein to enable them to lay their eggs before they die.

Why do they swarm me when I walk outside?

We put our carbon dioxide. Mosquitoes are very attracted to carbon dioxide, unfortunately. As stated above, they need their meals to reproduce.

What does the City use to spray for mosquitoes?

We use two different solutions to treat adult mosquitoes. These include Mosquitomist ONE ULV & Biomist 4+4 ULV. Our Mosquito Control team switches solutions to help prevent mosquitoes from building an immunity to these treatments.
We also use a larvicide, Altosid or Natular briquests to treat popular mosquito breeding areas like drainage ditches and other areas that hold water.
You can find more information on these solutions by visiting https://www.portlandtx.com/247/Mosquito-Control (link). The links are below the map at the bottom of the webpage.

Is this solution safe for me, my family, and my pets?

All the products we use are Environmental Protection Agency (EPA) approved. The solutions we use are environmentally friendly, but we do ask residents to stay inside while the crews spray their street, just in case.

How do you determine when to spray for mosquitoes?

Our Mosquito Control team regularly collects mosquito “counts” & when requested by residents.
- For mosquito counting, our crews go out to areas to collect information on the number of mosquitoes in an area. If the crews collect 5 or more mosquitoes in a 3-minute time frame, we will spray the area.

What is the process for spraying?

After we collect the mosquito counts and resident calls, we will go out to treat the areas of standing water and other popular breeding grounds with the larvicide. Our crews will spray in the mornings or evenings, depending on when the mosquitoes are most active. Lately, these mosquitoes are most active in the evening, so we have been doing citywide spraying in the evening between 8:00 p.m. to 11:00 p.m.
- The mornings have been used for pre-treatments and spraying areas the trucks cannot reach that have a high rate of infestation. Crews begin these activities around 4:00 a.m.

How often can the City's Mosquito Control team spray?

How does the weather affect spraying?

Winds must be 10-15mph for spraying to be most effective. The wind helps agitate the mosquitoes and helps carry the mist further to cover more areas. The spray is most effective when the droplets land on the mosquitoes’ wings.
If the winds are too weak, too strong, or it is raining, we will not spray since the solution will not be effective.

What are some tips to help prevent mosquitoes around our homes?

Empty all items with standing water (i.e. empty flowerpots, bird baths, unused tires, etc.)
Keep your yard trimmed
Clean out any gutters around the house
You can also get yard treatments to help reduce the breeding areas in your backyard, where our trucks cannot spray