Mosquito spraying decimates honey bees

In the sunny and tranquil village of Islamorada in the Florida Keys, beekeeper Jamie Hulet was caught off guard by a spray of pesticide. She writes: “We had a mosquito plane fly overhead this morning around 0700 and the chemicals they released killed thousands of bees. I have four Langstroth hives and all of them have piles of dead bees around them, as well as all over my property.”

Every year I hear stories like this, often from southern states that have problems with mosquitoes. But other states also have issues, especially in agricultural areas. What’s a beekeeper to do?

Fair warning

There seems to be a lot of variability in how much notice you get about spraying—if any—and how the word is spread—if at all. Here where I live, the Washington State Department of Natural Resources manages the Capitol State Forest and other lands. Over the years they have worked with us on several occasions, and we regularly get written announcements of management activities such as spraying and controlled burns. I consider our DNR to be an exceptionally good neighbor.

Many years ago when I lived in San Diego County (before Internet), spraying schedules were published in local newspapers. I don’t know how it’s done now, but back then I appreciated the updates. Even if you happened to miss the article, there was enough lead time that word spread.

However, not all jurisdictions are so courteous. Jamie was not aware there was a contact list for the Keys, so she had no notice and her bees paid the ultimate price. Once she discovered who to contact, she was told they only give about 12 hours notice.

How much notice is necessary?

The way I see it, if you tell me at 7 am that my property will be sprayed at 7 pm, there is little I can do for my bees. They are already out and about and I can’t go round them up. It seems like 24 hours should be a minimum.

Jamie was told the schedule changes quickly along with wind patterns, so the go or no-go decision can switch rapidly. Still, it seems like they could schedule in advance and give ample notice. Then, if it didn’t happen, there would be no dire consequence. They could just reschedule and try again.

Collateral damage from mosquito spraying

From an environmental point of view, the collateral damage from such spraying must be huge. Jamie said, “I live about 100 feet from the Atlantic Ocean. I can’t understand why mosquito planes are allowed to fly over the ocean and Florida Bay dropping these chemicals on the aquatic life.”

I agree and, naturally, my first thought was the native bees—the ones no one can protect. When I mentioned it to my husband, his first thought was the birds: either they eat poisoned insects (and fish) or else there is nothing left to eat and the birds starve. They can die either way.

It’s complicated

While there is certainly the issue of human health and mosquito-borne disease, there is also the question of what happens after we kill everything that supports human life. I often wonder if spraying isn’t a knee-jerk reaction to “The government must do something!” rather than a well-reasoned plan for long-range health and prosperity for both humans and the planet.

Jamie added, “I’ve been reading a few news articles online about beekeepers complaining about the planes in other states, but it doesn’t seem like there has been any changes based on complaints. There is not a strong community of beekeepers in the Florida Keys so I’m not sure how much my one voice will make a difference.”

I can sympathize with that thought. As our population continues to expand, each individual voice is a lesser part of the whole. Still, we shouldn’t give up. We need people who speak up and make us aware, even if it seems fruitless much of the time.

What is your experience?

Jamie and I are interested in knowing if you’ve ever had problems with spraying and, if so, how those problems were resolved—or not. It’s definitely an ongoing conflict, and as soon as I think reasonableness will ultimately prevail, something like this happens again. So please let us know: What’s a beekeeper to do? What did you do?

Honey Bee Suite

Thousands of dead bees littered the ground after aerial spraying for mosquitoes in the Florida keys.

Thousands of dead bees littered the ground after aerial mosquito spraying in the Florida Keys. © Jessica Stone.

A pile of dead bees in front of the hive is often a sign of pesticide poisoning.

A pile of dead bees in front of the hive is often a sign of pesticide poisoning. © Jamie Hulet.

Sick bees often remain outside so as not to infect others.

Sick bees often remain outside so as not to infect the others. © Jamie Hulet.

In the Keys, everything gets dosed with pesticide, even the water.

In the Keys, everything gets dosed with pesticide, even the water. © Jamie Hulet.

Dead bees littered the entire property.

After mosquito spraying, dead bees littered the entire property. © Jessica Stone.



  • Thanks, Rusty, for my dose of depression for the day.

    Also, I can see myself as a Marvel Super Villain. Instead of Mosquito Spraying I could have Human Spraying!

    (Also, and completely off topic, did you know that when you splash watermelon juice on your computer screen and then wipe it off with the rag you were wiping off other watermelon spillage, it doesn’t actually clean your computer screen?)

    • Roberta,

      Don’t know if I follow the watermelon thing, but okay.

      As for depression, think how Jamie feels. That’s a bad day.

      • Oh, sorry, just that I was trying to write and eat watermelon and wound up with smeared screen. I thought it would be funny and anti-depressing, but it might have been the failure mode of clever.

        Also, in Connecticut we register our hives with the State Entomologist (who may be the same as our Apiary Inspector & Master Beekeeper–just one person for the whole state of Connecticut!) and in return we’re supposed to be warned about pesticide use in our area. I’ve never gotten any warning. Homeowners use pesticides all over the place, but the promised warnings may be only for agribusinesses and government sprayings. Fortunately, it’s still mostly woods, swamp, and hay meadows around me, and the pesticides are mostly confined to the green desert lawns. I hope.

      • It is obscene that the spraying with toxins even happened. I live on the east coast of Canada where we have terrible black fly and mosquito problems. Several years ago our communities started using Vectobac [Bacillus thuringiensis]. it is a naturally occurring bacteria that kills about 95% of those bugs’ larvae naturally. It is made up in large batches like yogurt, then dried to a powder that is later mixed into a slurry and thrown across streams for black flies and bran balls chucked into stagnant waters for mosquitoes. Thus used it kills approximately 95% of the larvae = that many fewer adults. Maybe the Luddites spraying wide-spectrum toxins in Florida could join the 21st century and get biological!

  • Oxitec modified males of a non-malaria-carrying but still dangerous mosquito species, Aedes aegypti (a carrier of dengue, zika and yellow fever, among other diseases), so that their offspring would be infertile. The firm claims that the species’s populations in the test areas dropped by 80 percent …

    But when it wanted to do a test release in the Florida Keys, it was stymied. The Florida Keys Mosquito Control District held a nonbinding referendum on the project in November 2016; the proposal was approved in the overall district but rejected by voters in the region where the release was planned, Key Haven. Oxitec is now trying to get approval for a different Florida test site.

    • Pete,

      That’s interesting. I know that some insects have been controlled effectively by male sterilization and it is relatively safe in comparison to other control methods. Too bad they didn’t get the okay.

      • It’s the GMO thing. Some people fear that GM mosquitoes might be worse than spraying. Not worse for bees, obviously. It was to be a very small trial, but if it worked, it could put an end to mosquito spraying.

        • Pete,

          Oh, I see. Thanks for clarification. I just remember sterile male insect releases from ages ago. I believe back then, before GMO, they irradiated the insects to make them all infertile.

  • Could you please comment on how you would prepare your hive if you know that they are spraying ahead of time.

    Additionally, how long does the residue remain on plants?

  • Hi Rusty,

    I know it’s been a while, hope all is well!!!

    I too was affected here in NYC, what gets me though, all season long, we suffered and made due with the mosquitoes, this year so far we’ve been really lucky, I have yet to use personal repellent. Last year, at the end of the season, August/September-coming into fall honey (Japanese pagoda and Knotweed) Bombardment!!!!
    Wound up losing 4 hives!!!

    The year before I was fortunate to have had the heads up and smoked the bees in late afternoon/evening and stapled screen to entrances and inner cover, no loses, waited 24 hrs after spraying and released the bees, by then, pesticides were gone. But again was given the heads up. One can actually google “Mosquito spraying in my area (type in zip code)“ and it comes up. Hope all is well!!!


    • Hi Tonybees! I’m really glad to hear from you. Good to know you’re doing well.

      Thanks for the tip about spraying info.

  • We saw extensive mosquito spraying in Texas post-Hurricane Harvey and many beekeepers claimed losses from this spraying. I’ve yet to see credible evidence from competent beekeepers that their losses were distinct from starvation losses, however. In the Coastal Bend, we spray for mosquitos aggressively and have no noticeable losses from truck spraying. One important difference in our post-Harvey spraying may be the quality of the applicator doing the work. Our contractor was top notch and did great work. The USAF also participated in the spraying and I’ve heard (again unverified) rumors that their work was less than perfect in protecting honey bees.

    Sorry for your bees. Your loss is clearly a pesticide hit, though I wander if it wasn’t from some other non-mosquito spraying. Hope you can recover from this. A lot of times the foragers take a hit and the colony can manage to pull through. Feed em!

  • Funny this should come up as last week I paid a call to a new this year beekeeper whose colony was in trouble. Turns out he’d had some kind of pesticide/poisoning event. Only a handful of bees, probably the youngest house bees, and the queen were left, so we are assuming the foragers found a very attractive but toxic forage source.

    This was during our honey flow, so it is unlikely they were foraging on anything but blackberry blooms…it may be that someone sprayed a hedgerow, or perhaps the bees found liquid ant bait put out in quantity (borax in sugar syrup)??

    • Janet,

      That’s sad. Last year I lost two mid-flow and I’m pretty sure they got into something that was sprayed. It completely wiped out two strong colonies in one day.

  • In Louisiana (Bossier Parish) we would call the police jury (no idea why they were in charge of spraying) and request to be left out of the spraying path. It usually worked.

  • I am sad to hear about the losses from mosquito spraying. My heart would just drop if I lost all my hives like that.

    From the CDC webpage (
    “How does aerial spraying work?
    …ŠAerial spraying occurs sometime between the early evening,
    close to sunset, and the early morning, close to sunrise….”

    “How will I know aerial spraying is going to take place?
    The dates and times of aerial sprayings will be announced in
    the local newspaper, on district websites, through public service
    announcements, by telephone, or through door-to-door campaigns”

    I signed up with FieldWatch when I started beekeeping, which I hope will alert me of planned sprays, and it alerts those who do spray of beehive locations…if they participate.

    We rarely have aerial spraying here in SW Ohio, but we do have a lot of agricultural ground with boom sprays and our orchard is just a couple hundred feet from our hives and another orchard is less than 2 miles from us with no chemical colony losses to my knowledge. Thankfully, I believe most farmers around here are careful to monitor wind and runoff. As farmers, we also take care to spray specific to a problem that is affecting the crop.

    I don’t know what the answer is, but it seems there should be a solution. Some kind of Mosquito Dunks(R) on a large scale?

    I agree, 24 hour public notice would be a big step in that direction. Announce it on the local news stations and on local beeping and hometown FB pages. We have access to a vast array of social media. It should be easy to alert everyone in this age.

    For us, make sure our apiaries are registered on FieldWatch and keep talking to make our voices heard that we need more than a 12 hour window to prepare our apiaries for spraying.

    • Alice,

      Excellent thoughts and thank you for all that information. I agree there should be a way to alert everyone.

  • Here in Wisconsin we have Fieldwatch and Driftwatch, and it’s been spreading to other states. We can pin our apiary locations on a map so that responsible applicators can notify us if they will be spraying.

    The applicator that sprays fields around me is very conscientious and only sprays pesticides at dusk and dawn when the air is the stillest. He consults the Fieldwatch map and overlays his spray area . There’s never been an issue, and he has spoken at our East Central Wisconsin Beekeepers Association to help allay fears and misunderstandings. There are responsible applicators, and I’m blessed to have one treating crops in my area.

    I haven’t heard of aerial mosquito spraying around here, but I would hope for ample warning. The only thing I heard of was ditch spraying, and that was a very contained spray, years ago. Now it’s bat houses and OFF!

  • Can you tell me when this happened; I read the article and can’t seem to find the date. We are currently organizing to update the notification requirements for mosquito spraying in one of our counties in SC. After a massive kill of millions of bees 3 years ago {see link below}, the county began notifying each registered beekeeper individually prior to spraying. Since then hundreds have registered. The county recently decided it was too time consuming to continue notifications and will post on “appropriate media before spraying”. Can’t get an answer, but believe it will just be a post on their website.

    • Jim,

      The date is at the bottom of the yellow box containing the post, just before the comments: July 6, 2019.

  • A friend sent me your emails because she knows how frustrated I have become with the way the mosquito issue has been handled in our community. The Dept of Agriculture website clearly states that if breeding grounds are controlled no need for spraying and offers to evaluate potential sites with mosquito counts. But our HOA opted for spraying and pyrethrin is used which has a half-life of 40 days in soil where it accumulates and is classified as a stage 3 carcinogen by FDA. I cannot get others to understand how “good bugs” are also destroyed etc and the value of controlling small stagnant accumulations of water, open corrugated pipes etc. I opted out of the spraying [MD HAS A FORM WHICH CAN BE SUBMITTED WITH A COPY TO HOA. I am now the neighbourhood witch and glad to be so!

  • Our village in Northern Illinois notifies us about 3 days ahead of time which is nice. From what I have heard (no proof either way) the chemical sprayed from a truck in the late evening is active until the sun hits it. Thus, it is not supposed to effect daytime flying insects ….. I do not have a service spray the actual yard but they village does spray from the street. Thankfully, I have not seen any noticeable losses in 4 hives.
    Good day!

  • My district provides 24 hour notice call warnings and this year switched over to email/text warnings. Overhead plane spraying occurs after dark “weather permitting” so here is what I do.

    I have 3 Langstroth hives. I soak a bedsheet in water and cover each hive around 7-8pm and then at 6 am remove it. I have not noticed any loss of bees.

    My neighbor hired a company to spray their yard and they did not notify me (even though I share honey with them) so I stopped the spray by telling the service man that I had bees. They delayed a day so I could cover my bees as I do with plane mosquito spraying. Again, I did not see any dead bees around the hive after they came back to spray.

  • Sadly, there is the bigger issue for aerial spraying for mosquitoes. Is it really effective enough to justify all the negative environmental impacts? How many days post-spraying before the mosquitoes were back. And yes this activity is very much a “the government has to do something”. We all need to challenge GOV officials as to what other steps are being taken to control mosquitoes. Are steps being taken to remove potential breeding areas, etc.? I am just a 2nd year beekeeper but I have been a PhD Entomologist for 39 years – working primarily in Ag and the seed industry. I hate insecticides – almost got killed once by mis-use (my own stupidity) but we still need them to protect our food and homes. YET we have to use them wisely and be much more restrictive on who can use them. I cringe every time I walk thru the home + garden section of a “big box” store and see what anyone can buy in regards to insecticides. That is nuts.

    So what do we do – be active and vocal. Talk with your neighbors. If you are in the countryside – talk to the farmers around you. Do not think that every spray application is a threat to your bees – be informed. Also do not think all is well if an organic farmer is nearby. Many of the certified organic insecticides are deadly to bees. Be informed. Good luck.

  • More than half of my bees died from an aerial spray with naled. They sprayed between 6 pm and 8 pm in the evening, when the bees where already inside the beehive, and there was enough poison 12 hours later, that several thousands bees died in the morning. Today, 5 days after the spraying, the bees are not able to fly and fall to the ground dying.

    However, this is what EPA has on their web page for Naled mosquito control:
    “3. Does naled’s use for mosquito control pose health risks to people?
    naled and its degradate DDVP degrade extremely rapidly on surfaces, and therefore EPA’s assessment shows that surface residues decline to a level that does not pose any potential concern within 5 minutes to 3.4 hours after application”
    How can I believe this study when the bees died 12 hours later and they continued to dye for 5 days.

    “8. How can beekeepers reduce the risk of bee exposure to naled?
    EPA does not anticipate that bees will have significant exposure to naled due to the timing of most spray operation”
    Obviously, these studies were not done with real bees or they would have seen that the results are devastating to bees.

    “7. Is naled harmful to wildlife?
    Risks to wildlife from aerial application of naled for mosquito control are minimal because naled is applied from several hundred feet above the ground, at low rates, and it does not persist in the environment.”
    In my case, naled persisted in the environment for 12 hours and that is how my bees were poisoned the following morning.

    When reading results of these studies, I have to ask myself who paid for those studies?

  • This is not about spraying, but it is about mosquitos.

    I live in southern MI where we are plagued with mosquitos every spring and summer. A few times when I was holding a frame of bees, I would observe a mosquito land on a bee and try to stick its mouth into it the bee’s abdomen. They failed, of course. Their mouthpiece just slid off the bee’s exoskeleton.

    Has anyone else ever heard of or seen this?

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