How to Protect Your Hives from Mosquito Control: a Resource for Beekeepers

Mosquito Control Employee fogging from a truck. Overimposed text says "How to Protect Your Hives from Mosquito Control: A Resource for Beekeepers"

Aerial mosquito control can be good for animals and people in your community (it helps reduce Zika and West Nile Virus) but is definitely bad for any bees that get caught in the fog.

There are multiple steps that both you and the local, state, and federal government can take to reduce the impact of sprays on your beehives.

Who is in charge of mosquito control?

There are multiple governmental and local entities in charge of mosquito control—from approving pesticides for safety to planning the location of spraying to the actual on-the-ground spraying—including:

Centers for Disease Control and Prevention (CDC)
Local Health Departments
Environmental Protection Agency (EPA)
State & Local Government Agencies (such as Counties)
State & Local Mosquito Control Departments

According to the article, Legal Authority for Mosquito Control and Pesticide Use in the United States:

Mosquito control laws exist at the state and local levels. Variation exists from state to state on whether state or local governments have primary control over needed interventions. In some states, it is the state government that has the primary authority over mosquito control, including pesticide use.

Pesticides used in Mosquito Control

Different agencies use different forms of insecticide for mosquito control (both larvicides for water application and insecticides for fogging and killing of full-grown mosquitos).

Mosquito Control Departments may also switch up the chemicals used in order to prevent tolerance or resistance to the chemicals by mosquitos.

Some of the common insecticides and chemicals used are:

Naled. Naled is listed as “the chemical spray of choice” for aerial mosquito control by the Environmental Protection Agency. The EPA states that Naled will kill any bees it comes in contact with (though exposure should be limited as typically mosquito control departments should spray when bees are not active).
Sumithrin (Anvil). According to the Rhode Island Department of Health, sumithrin is one of the safest mosquito-control products. The product is used in several other states, including Alabama, Arkansas, Delaware, Florida, Illinois, Louisiana, Massachusetts, New York, New Jersey, North Carolina, and Texas.
Permethrin. Permethrin is listed as being used in Florida mosquito control.
Etofenprox (Zenivex). InsectCop, a resource for pest control, states that Zenivex is a common pesticide used during adult mosquito fogging.

Check with your local mosquito department to confirm what chemicals are currently being used for mosquito prevention.

Reducing harm to apiaries and bees when spraying happens

There are key steps to take to help prevent mosquito fogging from hurting your hives.

Keeping Track of When Mosquito Spraying Happens

According to the CDC, beekeepers should be notified (or at least be able to get publicly available information) that aerial spraying is taking place through:

Local newspaper
District websites
Public Service Announcements
Social Media
Telephone Calls
Door-to-Door campaigns

Actively monitoring and checking websites or reaching out to the Mosquito Control Department (we have a list linking to every state’s Mosquito Control Department at the bottom of this post) will keep you up to date.

Proactively Be in Contact with Your Local Mosquito Control Department

Proactive communication is one of the #1 ways to prepare for a spraying. Beekeeping is not a new practice, so your local Mosquito Control Department may already have precautions in place to protect pollinators.

Along with keeping track of the publicly available information on when sprayings occur, reach out to your local Mosquito Control Board (we have a list of their contacts state-by-state at the bottom of this post):

Don’t be combatant. When working with agencies, you catch more flies with honey than vinegar! Remember that everyone at the Mosquito Control Department is trying to do the best they can to keep people and wildlife as safe as possible while doing their jobs and working within budgetary and resource constraints. They are not an enemy!
Share your hive locations. The Mosquito Control Department will be able to tell you if the location of your hive is a known spray/trouble-mosquito zone.
Share the location of other local beekeepers’ hives. If you are part of a bee club or organization, or know local beekeepers, get a list of their hive locations and provide that to the department.
Ask the Mosquito Control Department to review the toxicity of their pesticides to bees. Again, many Mosquito Control Departments are trying to act in the best interest of pollinators already. However, requesting a review of the pesticides used may result in a lower-toxicity chemicals being used.
Ask information about the pesticides used. The Mosquito Control Department is the expert on what is being used out in the field. Contacting them directly will get you a list of exactly what insecticides they are planning to use.
Ask to Mosquito Control Department to notify beekeepers in advance before spraying. This of course depends on the resources the Department has, but they may be able to contact beekeepers specifically before spraying and provide them with advanced notice.

Covering Your Hives to Protect them from Mosquito Spray

This is a location-dependent and insecticide-dependent advice. Mosquito spraying typically happens at night, dawn, or dusk, when honeybees are in the hive and people, wildlife, and other insects may be less active. Beekeepers can choose to:

Move the hives to a different area that is not going to be sprayed.
Block the hive entrance with a hive entrance reducer so that bees don’t come out during the time period that the pesticide is still active.
Cover the hives with plastic sheet or a cloth (such as wet burlap) to protect them from direct contact with the spray.
Provide fresh water / sugar water for the bees to consume over recently-sprayed plants and water sources if needed (I know that you can lead a bee to water but can’t make it drink, but if the pesticide used is worrying you, it doesn’t hurt to try).
Let your bees out as soon as it is safe so that they don’t overheat. When it is safe is completely dependent on what type of chemical is used during the spraying.

Again, this is location-specific and pesticide-specific advice. For example, the University of Florida IFAS Extensions recommends not covering your hives and closing them up because it can lead to over-heating in the hot Florida weather.

Do not cover colonies with plastic or other covers when a spray event will occur. This could cause colonies to overheat and will lead to other problems.

You must make your own informed decisions on how to protect your apiary, and that includes taking into account local conditions.

Do Not Spray Sign or Apiary Signs

It can be helpful to purchase or create a sign that lets both truck-based mosquito foggers and pesticide applicators know there is an apiary nearby. One concern to take into account when doing this is beehive theft. If you are in a high hive-theft area, it may be a risk to let potential thieves know where your hive is located. However, if that is not a risk in your local area, a sign can inform on-the-ground mosquito sprayers of your hives.

For example, in Ohio, it is required by law that beekeepers register their apiaries with the state (and renew it every year) and include their name and phone number visibly in every apiary they own. This is helpful in two ways:

Apiaries are on record with the state, and therefore (hopefully, if nothing goes wrong), state mosquito control spray or pesticide/insecticide applicators should know where they are located, and the contact information of the beekeeper
If an apiary is not registered but a mosquito control spray or pesticide/insecticide applicator stumbles across one, they will be able to contact the beekeeper and give them warning of the spraying.

Learn the Laws for your State and County

Again, using Ohio as the example, it is also law that pesticide applicators that are using chemicals labeled toxic to bees give beekeepers 24 hours notice if:

The crop they are treating is in bloom
The field they are spraying is more than ½ an acre
The spray is within ½ a mile of an apiary

Learn your local laws regarding beekeeper notice periods and figure out if there is any corrective or preventative action you can take to protect your hives.

What if my bees are on someone else’s land?

If you have an outyard or beeyard on someone else’s property, it is wise to include in the lease or agreement for that property that the property owner agrees to having their property on the local Do Not Spray list for your local agencies.

LeaseHoney has put together a handy beekeeper-landowner lease agreement that includes a provision for this (along with many other provisions that are important to beekeepers).

Here’s How Contact Mosquito Control Where You Live

The National Pesticide Information Center has a handy map that you can click on to learn more about the Mosquito Control District where you live and contact the person. For convenience, we’ve included the direct links to each state as well below.

Center for Disease Control & Prevention Contact Information
Telephone: 970-221-6400
Fax: 970-221-6476
E-mail: dvbid@cdc.gov
web site: https://www.cdc.gov

Information on pesticides used in mosquito control can be obtained from the state agency which regulates pesticides, or from the National Pesticide Information Center (NPIC) West Nile Resource Guide.

National Pesticide Information Center Contact Information
1-800-858-7378 – daily except holidays. Callers outside normal hours can leave a voice mail message.
E-mail: npic@ace.orst.edu
Web site: http://npic.orst.edu/

Information on mosquito control programs can also be obtained from the American Mosquito Control Association (AMCA) website. This site also lists many county mosquito agencies.

Local Health Departments

Like mentioned before, Health Departments are often involved in mosquito spray programs. The CDC does a great job listing out all the health department contacts in the US.

How to Protect Your Hives from Mosquito Control: a Resource for Beekeepers