Bees face heavy pesticide peril from drawn-out sources

April 20, 2017 by Blaine Friedlander, Cornell University
A honeybee collects the pollen from an apple blossom. Credit: Kent Loeffler/Provided

Honeybees - employed to pollinate crops during the blooming season - encounter danger due to lingering and wandering pesticides, according to an analysis of the bee's own food.

Researchers used 120 pristine honeybee colonies that were placed near 30 apple orchards around New York state. After allowing the bees to forage for several days during the apple flowering period, the scientists examined each hive's "beebread" – the bees' food stores made from gathered pollen – to search for traces of .

In 17 percent of colonies, the beebread revealed the presence of acutely high levels of pesticide exposure, while 73 percent were found to have chronic exposure.

The new Cornell study was published April 19 in Nature Scientific Reports.

"Our data suggest pesticides are migrating through space and time," said lead author Scott McArt, assistant professor of entomology, who explained that bees may be gathering pollen from nontarget wildflowers, field margins and weeds like dandelions where insecticides seem to linger.

"Surprisingly, there is not much known about the magnitude of risk or mechanisms of when honeybees are brought in to pollinate major agricultural ," he said. "Beekeepers are very concerned about pesticides, but there's very little field data. We're trying to fill that gap in knowledge, so there's less mystery and more fact regarding this controversial topic."

More than 60 percent of the found pesticides were attributed to orchards and surrounding farmland that were not sprayed during the apple bloom season, according to the study. McArt said that persistent insecticides aimed at other crops may be surrounding the orchards. In addition, pre-bloom sprays in orchards may accumulate in nearby flowering weeds.

Honeybees create honey in their hive through the topped-out combs, and they keep beebread - their food - in the other combs. Credit: Emma Mullen/Provided

"We found risk was attributed to many different types of pesticides. Neonicotinoids were not the whole story, but they were part of the story." he said. "Because neonicotinoids are persistent in the environment and accumulate in pollen and nectar, they are of concern. But one of our major findings is that many other pesticides contribute to risk."

Mass-blooming crops flower in big bursts during the pollination season, so crop producers rent armies of honeybees to supplement the work of . "There are so many flowers at one given time, often there may not be enough wild bees to perform sufficient pollination services," said McArt.

Crop pollination by insects, particularly bees, can be valued at more than $15 billion annually to the U.S. economy, according to research by Nicholas Calderone, professor emeritus of entomology. Producers and beekeepers are now concerned about the high rates of hive declines – estimated to be about 42 percent in 2014-15 domestically. In New York, the losses are often over 50 percent.

To understand the economics, beekeepers may charge more than $100 per colony for pollination services for apple producers in New York, almond producers in California and blueberry growers in North Carolina. For large farms, several hundred to a thousand pollinating colonies are brought in via large trucks.

Commercial beekeepers sometimes assume they will lose entire colonies, which is why pollination service rates have tripled or quadrupled over the past 15 years, McArt said. He recently shared his research with growers at a New York State Integrated Pest Management meeting, and several farmers said they are interested in altering crop management practices to reduce honeybee injury.

The New York State Department of Environmental Conservation and the Department of Agriculture and Markets assembled a Pollinator Protection Plan in 2016. Scientists are developing best management practices, reviving pollinator populations, researching and monitoring, and developing outreach and educational programs for beekeepers and producers.

Co-authors on the study, "High Pesticide Risk to Honeybees Despite Low Focal Crop Pollen Collection During Pollination of a Mass Blooming Crop," are lab manager Ashley Fersch; graduate student Nelson Milano; Lauren Truitt '17; and former research associate Katalin Böröczky.

Explore further: Pesticides harm wild bees, pollination in N.Y. orchard crops

More information: Scott H. McArt et al. High pesticide risk to honey bees despite low focal crop pollen collection during pollination of a mass blooming crop, Scientific Reports (2017). DOI: 10.1038/srep46554

Related Stories

Planting native vegetation for productive crops

March 24, 2017

The University of Adelaide, working with South Australian industry groups, is helping farmers and growers design and implement native plantings to support bee and other insect populations needed to pollinate their crops and ...

Honeybees entomb to protect from pesticides

April 8, 2011

(PhysOrg.com) -- With the drastic rise in the disappearance of honeybee colonies throughout the world in recent years there has become a large focus on the study of honeybees and the effects of pesticides on their colonies. ...

Bee flower choices altered by exposure to pesticides

March 14, 2016

Scientists have shown that low levels of pesticides can impact the foraging behaviour of bumblebees on wild flowers, changing their floral preferences and hindering their ability to learn the skills needed to extract nectar ...

The real reason to worry about bees

September 10, 2013

Honeybees should be on everyone's worry list, and not because of the risk of a nasty sting, an expert on the health of those beneficial insects said here today at the 246th National Meeting & Exposition of the American Chemical ...

Recommended for you

Houseplants could one day monitor home health

July 20, 2018

In a perspective published in the July 20 issue of Science, Neal Stewart and his University of Tennessee coauthors explore the future of houseplants as aesthetically pleasing and functional sirens of home health.

LC10 – the neuron that tracks fruit flies

July 20, 2018

Many animals rely on vision to detect, locate, and track moving objects. Male Drosophila fruit flies primarily use visual cues to stay close to a female and to direct their courtship song towards her. Scientists from the ...

Putting bacteria to work

July 20, 2018

The idea of bacteria as diverse, complex perceptive entities that can hunt prey in packs, remember past experiences and interact with the moods and perceptions of their human hosts sounds like the plot of some low-budget ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.