UF/IFAS Researchers Share Safest Ways to Spray for Zika Mosquitoes, Protect Bees
Newswise — GAINESVILLE, Fla. --- Florida beekeepers are concerned after 2.5 million bees that were killed during an aerial spraying with Naled/Dibrom for Zika-carrying mosquitoes in Dorchester County, S.C. Now, Floridians are looking for ways to avoid the same tragedy. Florida is the third-largest beekeeping state in the nation.
Researchers are not surprised that the South Carolina incident has Florida beekeepers worried, said Fred Fishel, professor of agronomy and director of the Pesticide Information Office.
“With the Zika cases in south Florida, and now that scientists have identified mosquitoes that carry the Zika virus, we would expect beekeepers to be concerned about increased pesticide application,” Fishel said. “But, registered beekeepers should be notified before an application of pesticides. That gives them time to protect their bees while spraying is conducted.”
There are pesticides that will not harm bees, but will kill mosquitoes, says William Kern, associate professor of urban entomology at the UF/IFAS Fort Lauderdale Research and Education Center.
“The larvaciding materials Methoprene should have very little impact on honey bee colonies and no mortality on adult honey bees. Bti, a biological pesticide, has no impact on honey bees,” Kern said. “The problem comes from the use of adulticides like Naled, pyrethrin, or resmethrin, that will kill exposed bees.”
Jamie Ellis, an associate professor of entomology and head of the UF/IFAS Honey Bee Research and Extension Lab, offers tips to help beekeepers minimize damage to bees: • Ask the Mosquito Control District to review the list of pesticides available to them and use those that are the least toxic to bees and have the shortest persistence in the environment. Remember that the Mosquito Control District will want to rotate chemicals to lessen the chance that mosquitoes will become resistant to any one product. Consequently, you may have to work with the team to identify a couple of lower-risk pesticides.• Encourage the mosquito control district to spray after dark, when bees are not flying. Remember, most mosquito control districts must spray at or just after dusk because that is when mosquitoes fly. However, the later in the evening that the mosquito control districts can spray, the better it is for the bees.• Work with the spray team to identify areas that need to be sprayed. Local terrain will determine the location of mosquito hotspots. Consequently, spray teams can review their spray area and maybe limit the amount of pesticide that they spray.• Create a list of local beekeepers and include their contact information. You can give this list to the local mosquito control district and ask them to notify all area beekeepers prior to spraying for mosquitoes. This is especially important when Florida Department of Agriculture and Consumer Services is conducting emergency mosquito control operations. A helpful reminder that a beekeeper can have colonies located all over the district will be instructive.
“Beekeepers need to remember that mosquito control districts work under certain constraints and may not be able to follow all of the recommendations above,” Ellis says. “The obligation is on the beekeeper to protect his/her bees.”
Ellis suggests placing hives in areas that are less likely to be exposed to spraying. Also, communication is key. “Communicate openly with local mosquito control districts about the importance of honey bees,” Ellis says. “Volunteer to give a presentation on bees to the employees so that they will understand the situation better.”
“Both Aedes aegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito) are found around houses,” Kern said. “These mosquitoes are associated with urban and suburban residential and recreational areas; therefore, backyard bee hives are at greater risk than hives placed in rural or unoccupied locations.”