What Chemicals Do Mosquito Spray Trucks Use?

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This is one of the most commonly asked questions whenever somebody hears that a mosquito spraying will happen in their neighborhood. Since these sprayings are becoming a more common with all the Zika virus, West Nile fever, and dengue fever threats floating around, I thought it would be beneficial for us to find out what precisely the mosquito trucks are spraying and how it can affect us.

What do the sprayings target?

Usually, both larvicides and adulticides are used when mosquito spraying happens in any area. This strategy is employed not only to get rid of all the adult mosquitoes in the area so that there is less of a chance that you will be bitten by a mosquito but also to get rid of mosquito larvae so there are no mosquitoes waiting to mature and cause more problems.

The sprayings take place in the evening or morning as these are the times when the mosquitoes are the most active.

What chemicals are actually used by the mosquito trucks?

One of the most commonly used ground foggings, or those done from a car or on foot, is Zenivex.

This is an effective pesticide that targets adult mosquitoes. For that reason, it usually is used in conjunction with a larvicide. It is an oil-based fogging solution that can be used in both urban and rural areas since it is approved for use even on agricultural crops.

The main active ingredient in Zenivex is etofenprox, an adulticide, which is an insecticide that targets adult insects by disturbing their nervous system when they come in contact with the chemical, eventually causing death.

Luckily, etofenprox insecticides and, therefore, by default also, Zenivex have low toxicity for birds. When the spray has dried, it becomes harmless to living creatures like bees and dogs as well (however, it is highly toxic to bees and other beneficial insects during spraying).


Mosquito spraying programs also use permethrin-based solutions, which is another insecticide (liquid fogger chemicals) that is long-lasting and efficient. It is low in toxicity to birds, dogs, and humans and somewhat toxic to cats. It is highly toxic to beneficial insects and aquatic organisms.

What should you do when spraying is scheduled?

All of these solutions, whether a permethrin-based one, Zenivex or an entirely different insecticide, are distributed with the help of an ultra-low volume (ULV) fogger, which can turn the liquid solution into a very fine fog, allowing the insecticide solution to penetrate into all of the small cracks where mosquitoes tend to hide.

Of course, any insecticide is still a poison, so if you want to be completely sure that you and your family and pets are not breathing it in, then I would suggest:

  1. Close your windows and doors when the spraying is scheduled.
  2. You should also keep your pets indoors.
  3. Always cover your beehives and fish ponds, as these insecticides harm bees and aquatic life.

However, people shouldn’t be that concerned about mosquito spraying because these insecticides are approved by the US Environmental Protection Agency, and the volume of insecticide used is very small. And, of course, the mosquito spray is much less harmful than what a mosquito could do to you if it were to bite you and infect you with a disease. So, even though some may worry that these sprayings are harmful, the truth is that they only affect our lives in a positive way. You can approach DIY backyard mosquito control in a similar manner.


Greta Garbo

My brother & I used to walk behind the mosquito trucks in the 70’s whenever they sprayed. We are. Oth in poor health. I was wondering if this was related to the chemicals in the fog that they sprayed. We thought it was fun to walk into it & did it way to many times. Are we paying the consequences now? I’m 61 & my brother is 58.


    It depends on what was used to kill the mosquitoes. If malathion or an organophosphate were used, which at that time were the more popular mosquito fogging chemical options, then running behind the mosquito truck as a kid shouldn’t be the cause for your poor health. Many think that DDT (which was banned in 1972 but actually isn’t even toxic to humans) was used as the fogging chemical and because of that associate mosquito trucks with poor health. But since DDT is a larvacide it wasn’t used in the fogging trucks, it was mainly put into the water to control mosquito larvae.


    YES!!! Roundup would have come out around the time you and your brother were kids being kids. We all liked doing things that seemed innocent but the after affects have proved to be deadly later in life. Learn about it and get tested for acetylcholinesterase aka Roundup toxins. This article is very eye opening.


    Roundup is for vegetation

    Say no to BS

    Contrary to the person that claimed DDT is not harmful to humans…. it has been banned in noncommercial use because it IS highly toxic! I just finished a research report on it’s toxicity…. and to be brief, YES it is highly likely that your poor health is an effect of inhaling and being so openly exposed to the pesticides. NEVER trust the people who make a profit off of said pesticides to tell you if it truly is harmful or not.

    If it has a poison control section… beware.


was just at a party where we ‘kids’ realized nearly ALL of the moms on the main mosquito truck route (1960s) have had breast cancer. kinda wishing someone would do a map/correlation. we’re assuming the new stuff is safe, of course… then again, our folks were told it was safe back then. (?)

just as important (maybe, more) is the new standing water in our village — the result of inappropriate building (marshes and low level ponds where there’s used to be grass, stagnant puddles where there used to be a flowing creek). in the last few weeks, they’ve dug trenches that don’t drain to culverts. with our heavy clay soil, these puddles simply aren’t draining (or even evaporating in 98 degree full sun).


    Go to CDC.gov and search for epidemiology section. You might have to call them, but epi is set up for this purpose. Blessings.


Our city truck has been fogging people’s backyards which go right by our vegetable garden, chickens, meat rabbits and honey bees – just feet away. I can’t imagine that this isn’t toxic to them, their water, their air and eventually, to us. Comments?


    It depends on what chemicals are being sprayed. I’d suggest you contact your local vector control district or government department and ask them what type of insecticide they use in your area.

Debbie D

In the town I live in.. I have had numerous trees and plants die after the town began their fogging. What can i do about this? It’s very frustrating planting plant and nice bushes and then all of a sudden the blooms dry up and fall off the flowering rose of sharon. And I had a white peach tree and tree was a young beautiful tree. Health and was just beginning to produce fruit. Then the fruit dried up and the leaves fell off and the tree died. All in a month. This is getting expensive and aggravating to say the least! And trying to get answers is like getting straight answers from a politition!


    This sounds awful! Unfortunately, I don’t think there’s much else you can do, other than talking to the officials. Have you also talked to your neighbors? Are they experiencing the same effects? Good luck figuring this out!


All the kids in my neighborhood ran behind the fog truck in the 60’s. We were told that the fog was vaporized no. 2 fuel oil. is that true ?


    Unfortunately, I don’t have much knowledge on what chemicals were used back then.

Eric Curtright

I live in Florida and I am using Bifin It and Suspend Polyzone in my Stihl backpack sprayer. Are these the best products to use? Should I rotate?
I have tried products containing Permethrin,Deltamethrin (Current), Bifinthrin (current), malathon,cyfluthrin,lambda-cyhalothrin. I dont expect miracles but I hope to reduce the population by at least 80%……Thanks


    The products are good, so they should be helping you. To give you a better chance, we suggest also taking other measurements, such as eliminating breeding grounds in the area. Check out our article about getting rid of mosquitoes and take a look at the section about yards.

Mark Zaspel

Is there a mosquito spray that won’t affect bees?

    Kristiana Kripena

    If mosquito yard spray is what you’re looking for then you should try the Mama Nature’s All-Natural Mosquito Spray. It’s effective as well as safe to all pollinators including bees.


I am a little bothered that they just came by and sprayed and we were not told ahead of time. We have our windows open and whole house fan on. I quickly closed it up but not until after the fact. A warning through the mail would have been nice. I don’t like mosquitos, I would have just liked a warning. Oh, and my cat is outside! I live in Sutter County


Sadly, this fogging is a big part of why we don’t have as many lightning bugs. There are more natural ways to keep the mosquito population down, like bats.


The woman above who comment about the “P pins on Control info” on the labeling. She is correct. That is a good indicator that its had some level of toxicity in at least some people.


Ron 12/7/20 live in a older subdivision outside of Houston Texas and some of my older neighbors freinds have said the neighborhood has been getting sprayed by truck for 35 years usually In the summer months May through Sept sometimes twice a week when it’s hot,how contaminated could this area be?


    Since we don’t know what kind of chemicals are being used, it’s hard to say. Though, usually, they use chemicals that aren’t dangerous once they have dried.

Bill Quay

I grew up on Jeckell Island Ga in the late 60s we would ride our bikes behind the Fog trucks every time they went down the streets , I had stage three esophageal cancer and I just found out I have Prostate cancer , I’m only 57 and I’m starting to wonder if it’s from the chemicals I was exposed to when I was younger if anyone has any information please respond
Bill Q


    You were probably running around in the fumes of DDT which has been banned in the US for quite some time now. While there is no conclusive evidence, some researchers do believe there might be a link between DDT exposure and cancer (as well as other health issues). Therefore, while we can’t confirm or deny it as the cause, it is one of the possibilities.

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