Protecting Honeybees as You Farm
Published on April 4, 2020
All involved with agriculture recognize the value of honeybees. Producers, knowing how difficult making a living in agriculture can be, can also appreciate the source of revenue honeybees provide fellow agriculturists, the beekeepers.
Managed and feral honeybee colonies across the country have declined from over four million in 1982 to just a little over three million by 1992. The last census of beekeepers with five or more colonies placed the tally at 2.67 million colonies as of Jan. 1, 2019. Visit bit.ly/honeybeenumbers for more detail.
Why the decline occurred is somewhat controversial. Some want to attribute most of the honeybee population decline to pesticide exposure from conventional agriculture practices. However, both the tracheal and Varroa mites, Acarapis woodi and Varroa destructor, respectively, were first detected in U.S. honeybee populations in the early 1980s. This discovery coincides with the initial steep decline in honeybee colony numbers.
This decline occured even before the coining of the “Colony Collapse Disorder,” a name used to describe the severe overwinter honeybee hive losses reported in 2006. Beekeepers surveyed by the U.S. Department of Agriculture National Agriculture Statistics Service (USDA-NASS) in 2019, still consider the Varroa mite the number-one stressor of their honeybees.
Many people are shocked to learn products sold by apiary supply companies as “medications” to treat Varroa mite infestations in hives are synthetic insecticides. They are applied inside honeybee hives in ways lethal to the Varroa mites, but sub-lethal to honeybees.
My point is, Varroa mites, the numerous pathogenic viruses they transmit, tracheal mites, small hive beetles and the occurrence of a second species of Nosema fungal pathogen are major factors in the decline.
Added on top of these diseases and parasites of honeybees, are the health stresses due to the intense commercial pollination services the almond industry demands every February.
I believe these factors have caused more problems for beekeepers over the last 30 years than have the good integrated pest management (IPM) on farms for common crop pests. However, I am not saying we cannot improve our farming practices or enhance the rural landscape to reduce risk to honeybees.
There are practices that can protect honeybees. One way is having pesticide applicators and local beekeepers communicate about their activities and locations of honeybee colonies.
By statute, beekeepers need to register colony locations with the Wyoming Department of Agriculture (WDA). Applicators need to notify beekeepers with colonies in the vicinity of treatments in time for them to take action to protect their insect livestock.
Honeybees can travel over four miles to get to the pollen and nectar the colony needs. Usually, honeybee colonies are close to the flower resources they need. Potentially, this is quite a large area a pesticide applicator needs to be aware of.
The WDA Technical Services Division has a mapping application on their website that gives the location of all registered beehives and is searchable, the map can be viewed at bit.ly/wyobeeapp.
The app’s accuracy, however, depends on beekeepers updating hive locations if they move their honeybees.
You, or your hired applicator, must read and follow the pesticide labels and obey the guidance they provide regarding drift management and pollinator protection. Honeybees can be contained in their hives for 24 hours easily in cool weather or even relocated if necessary for protection when a field they are visiting needs treated.
The time of restriction or the decision to move hives depends on the insecticide and crop. Treating blooming confectionary sunflowers for sunflower moth larvae is an example. The sunflowers will still need honeybee pollination, so the grower and the beekeeper have to work together to ensure each other’s success.
I often read pesticide applications be conducted in the evening after bees have returned to their homes. In theory, this is fine. However, air temperature inversions, which can cause off-target pesticide drift, often develop in the early evening.
If conditions exist that might drift insecticides onto flowers outside a field where honeybees are foraging, it would be better to treat when weather conditions ensure all of the pesticide stays on the crop field and have your beekeeper restrict honeybees’ access to the field while it is hazardous to them.
The North Dakota State University Extension publication, Air Temperature Inversion Causes, Characteristic and Potential Effects on Pesticide Spray Drift, helps explain and is available at bit.ly/airtempinversions.
The inherent toxicity of the insecticide, the length of its residual activity, the formulation of the product and the timing of the application can have a huge influence on the risk to honeybees and other pollinators.
Herbicides are unlikely to cause direct harm to honeybees. Some fungicides when tank mixed with insecticides have a synergistic effect that increases the toxicity of the mixture to honeybees.
A Pacific Northwest Extension publication entitled, How to Reduce Bee Poisoning From Pesticides, is available to provide detailed guidance on pesticide selection at catalog.extension.oregonstate.edu/pnw591.
Keeping part of their lands in vegetation that can provide flowers all growing season is another way farmers can enhance the rural landscape for honeybees. Local USDA Natural Resource Conservation Service offices have programs and incentives to help conserve habitat for honeybees. You can learn more at bit.ly/foodforbees.
Asking seed companies to stop coating oil and grain seeds with systemic insecticides is another way farmers can help honeybees and themselves. The idea of an insecticide being applied without a specific action threshold of pest pressure goes against a basic principle of IPM.
The constant selection pressure of a single insecticide mode of action will cause and raise pest population resistance and eventually render that class of insecticide useless.
Research at Purdue University, published in 2017, showed clothianidin, a neonicotinoid class insecticide, coated corn seeds didn’t result in increased yield versus untreated seeds. It is non-intuitive that there can be extensive pesticide drift from insecticide coated seeds.
However, the same researchers also demonstrated that the dust vented from the air seeders, commonly used for planting corn, contained enough clothianidin residue from the seed coating to be hazardous to bees foraging near the fields.
The vented residue dust drifted in the wind and contaminated flowers in meaningful amounts almost 100 yards downwind from corn field edges after planting, the farthest distance sampled in the study.
A summary of the study can be found at bit.ly/cornseedtreatment.
This is not the only seed coating, systemic insecticide and crop system studied that has shown little economic benefit to the farmer and increased the hazard to honeybees.
The original peer reviewed publication, Planting of Neonicotinoid‐Treated MaizePoses Risks for Honeybees and Other Non‐Target Organisms Over a Wide Area Without Consistent Crop Yield Benefit, is available from the Journal of Applied Ecology, Volume 55, Issue 3, Journal of Applied Ecology page 1565-1565. First Published online November 27, 2017 at bit.ly/maizeseedstudy.