The following article was written for Wild Ones Lexington newsletter September 2016
We seem to be seeing an increasing amount of advertising for mosquito spraying services in our area. We are also noticing lower numbers of pollinators, especially butterflies. While populations of our pollinators are suffering due to many factors, could the chemicals used to kill mosquitos also be a culprit? After research, questioning, and eyebrow raising, I have come to the conclusion that yes, our pollinators are likely taking a hit.
If you web search ‘mosquito spraying Lexington, KY’, you will find some companies who specialize in the service, some general pest control companies, and even the Lexington Health Department who sprays for mosquitoes. On their websites, there is a lot of marketing about diseases carried by mosquitoes and how much of a nuisance they are. While mosquitoes can carry disease and be bothersome, do the negative effects of spraying outweigh a mosquito free yard? When it comes to pollinators, other beneficial insects, our environment, and health, then there are negative consequences.
I spoke with one company that specifically sprays for mosquitoes here in town. The chemical they use is called Bifenthrin 7.9, a pyrethroid type of insecticide, which is the manmade version of pyrethrin. Both are common ingredients used in many insecticides. Currently in the U.S. there are over 600 products containing the chemical bifenthrin.
On the Safety Data Sheet provided by the EPA (available online), it states that this chemical is highly toxic to bees and fish. Like many insecticides, it is non-selective and kills by attacking the nervous system of a wide variety of insects including caterpillars, butterflies, and moths. The company I spoke with said this chemical targets mosquitoes, but wouldn’t say it specifically kills mosquitoes only.
Like other companies, they apply the chemical using a using a backpack sprayer where it is sprayed upward onto the underside of leaves on trees and shrubs in order to target roosting mosquitos. They said they were ‘bee-friendly’ by avoiding spraying flowers. I asked about the possibility of drift, and they said it’s not an issue because an additive makes it tacky to stay on the foliage. However, there is still some possibility of drift as it is a mist sprayed in the air.
The company said they generally spray early in the day to allow the chemical to dry before a family comes home in the evening. If so, these chemicals are being sprayed at times of the day pollinators are active. To have a continuous mosquito free yard, spraying has to occur every 21 days. The company does provide an all-natural treatment with natural essential oils, but the Lexington franchise of this company does not offer this service.
Since the chemical is sprayed into trees, how many caterpillars are being killed in this treatment considering the major host plants for caterpillars are trees? Also, what could this be doing to our wild birds when they eat an infected caterpillar or other insect?
The Fayette Co. Health Department sprays for mosquitoes using a different method. The chemical is sprayed off the back of a tank truck into the streets where it can drift into your front yard. They use the chemical DUET which has the active ingredients of Prallethrin and Sumithrin. While these are different insecticides, they act very similar and are also very toxic to bees and fish. DUET however only kills the adult mosquitoes flying in the air and not larvae. The health department sprays between the hours of 3-6am, so it hopefully limits contact with bees (and humans) directly.
On the health department’s website you can find more information, see the spraying schedule, and find a routing map. The health department starts spraying in May and sprays each route twice a month until temperatures fall below 55 degrees at time of spraying or the first frost. You may opt out to have the area around your home sprayed by contacting the health department at http://www.lexington health department.org or 859-252-2371.
The health department states DUET is a very safe chemical and you can go outside immediately after application. Some cities in the US including Louisville actually spray this chemical aerially over the city.
The government and chemical companies say these chemicals are safe, but environmental organizations are concerned. We can all take measures to reduce mosquito populations on our property without resorting to insecticides. Basic steps to take to limit contact with mosquitoes: minimize standing water where insects can reproduce, wear lightweight long sleeves to prevent bites and use all-natural bug repellents. There are some machines out there that repel mosquitoes without insecticide.
It is important to be aware of chemicals like these being used in our community and to voice our opinion about them. I expressed my concern to the health department and made sure my street was not on the spraying route.
UPDATE: A couple of days after this article was published…
Millions of bees have been killed in a South Carolina town due to aerial mosquito spraying. Flowertown Bee Farm and Supply had 46 hives, which was home to millions of bees that supplied the honey and other goods for their business. This doesn’t even take into account how many native bees, other bee hives in the area, and just beneficial insects in general that were affected by the spraying. The scenes of the bees lying in piles around the hives is devastating. The owner of the farm now has to destroy all of her equipment and kill the rest of the bees because they are contaminated. It’s a sad story.
There haven’t been any accounts of mosquitoes carrying the Zika virus in South Carolina, but this city decided to go ahead and douse the city with insecticide. The owners of the bee hives didn’t know about the spraying, and even if they did, there would be little they could do except plead for them not to spray near their area. The news states the city announced in a few places about the spraying just two days beforehand. The spraying occurred at 8am, when the bees were already active in the day. If the spraying had been done at night, the outcome could have been less devastating.
While it has been devastating for bee hobbyists and those who operate a business based on their bees, it has been more devastating to them and everyone seeing all their bees perish. We can only hope that instances like this make people more aware of how we’re using insecticides nonchalantly. If we kill our bees, we will have more to worry about than the Zika virus. It’s a catch 22, it seems we’re doing more harm spraying for mosquitoes than not.
EARTHeim Landscape Design Lexington Kentucky 
thank heavens someone in this city has realized the devestation caused by chemical agriculture/chemical horticulture and the never ending war against weeds and insects. Keep up the good work.