Pesticide Cocktail Can Harm Honey Bees

PHYS.ORG University of California at San Diego April 10, 2019

A honey bee collects pollen. Credit: James Nieh, UC San Diego

A honey bee collects pollen. Credit: James Nieh, UC San Diego

A recently approved pesticide growing in popularity around the world was developed as a "bee safe" product, designed to kill a broad spectrum of insect pests but not harm pollinators.

A series of tests conducted over several years by scientists at the University of California San Diego focused on better investigating the effects of this chemical. They have shown for the first time that Sivanto, developed by Bayer CropScience AG and first registered for commercial use in 2014, could in fact pose a range of threats to honey bees depending on seasonality, bee age and use in combination with common chemicals such as fungicides.

The study, led by former UC San Diego postdoctoral fellow Simone Tosi, now at ANSES, University Paris Est, and Biological Sciences Professor James Nieh, is published April 10 in Proceedings of the Royal Society B.

Pesticides are a leading health threat to bees. After years of growing concerns about systemic toxic pesticides such as neonicotinoids and their harm on pollinators, Sivanto was developed as a next-generation product.

Sivanto's "bee safe" classification allows it to be used on blooming crops with actively foraging bees. Currently, pesticides are approved for widespread use with only limited testing. Perhaps most importantly, the interactions between new pesticides and other common chemicals such as fungicides are not fully tested. Sivanto's product label does prohibit the pesticide from being mixed in an application tank with certain fungicides. However, bees can still be exposed to Sivanto and other chemicals (pesticide "cocktails") that are commonly used in adjacent crops or that persist over time.

Honey bee workers inside their nest. Credit: Heather Broccard-Bell

Honey bee workers inside their nest. Credit: Heather Broccard-Bell

Starting in 2016, after reviewing documents describing Sivanto's risk assessments, the scientists conducted several honey bee (Apis mellifera) studies investigating effects that were not previously tested, particularly the behavioral effects of chemical cocktails, seasonality and bee age. The scientists provided the first demonstration that pesticide cocktails reduce honey bee survival and increase abnormal behaviors. They showed that worst-case, field-realistic doses of Sivanto, in combination with a common fungicide, can synergistically harm bee behavior and survival, depending upon season and bee age. Bees suffered greater mortality—compared with control groups observed under normal conditions—and exhibited abnormal behavior, including poor coordination, hyperactivity and apathy.

The results are troubling, the researchers say, because the official guidelines for pesticide risk assessment call for testing in-hive bees, likely underestimating the pesticide risks to foragers. Honey bees have a division of labor in which workers that are younger typically work inside the colony (in-hive bees) and foragers work outside the colony. Foragers are therefore more likely to be exposed to pesticides.

"We found foragers more susceptible," said Nieh. "They tend to be older bees and therefore because of their age they can suffer greater harm."

The harmful effects of Sivanto were four-times greater with foragers than with in-hive bees, the UC San Diego study showed, threatening their foraging efficiency and survival. Both kinds of workers also were more strongly harmed in summer as compared to spring.

"This work is a step forward toward a better understanding of the risks that pesticides could pose to bees and the environment," said Tosi, a postdoctoral fellow and project manager at the Epidemiology Unit. According to the authors, the standard measurements of only lethal effects are insufficient for assessing the complexity of pesticide effects.

A honey bee forages on flower. Credit: Heather Broccard-Bell

A honey bee forages on flower. Credit: Heather Broccard-Bell

"Our results highlight the importance of assessing the effects pesticides have on the behavior of animals, and demonstrate that synergism, seasonality and bee age are key factors that subtly change pesticide toxicity," Tosi said. Cocktail effects are particularly relevant because bees are frequently exposed to multiple pesticides simultaneously.

"Because standard risk assessment requires relatively limited tests that only marginally address bee behavior and do not consider the influence of bee age and season, these results raise concerns about the safety of multiple approved pesticides, not only Sivanto," said Nieh, a professor in the Section of Ecology, Behavior and Evolution. "This research suggests that pesticide risk assessments should be refined to determine the effects of commonly encountered pesticide cocktails upon bee behavior and survival."

Sivanto is available in 30 countries in America, Africa, Asia and Europe, with 65 additional countries preparing to approve the product soon. Tosi points out that "because Sivanto was only recently approved, and no monitoring studies have yet investigated its co-occurrence with other pesticides after typical uses in the field, further studies are needed to better assess its actual environmental contamination, and consequent risk for pollinators."

"The idea that this pesticide is a silver bullet in the sense that it will kill all the bad things but preserve the good things is very alluring but deserves caution," said Nieh.

Explore further Pesticides and poor nutrition damage animal health

More information: S. Tosi et al. Lethal and sublethal synergistic effects of a new systemic pesticide, flupyradifurone (Sivanto ® ), on honeybees, Proceedings of the Royal Society B: Biological Sciences (2019). DOI: 10.1098/rspb.2019.0433

Journal information: Proceedings of the Royal Society B 

Provided by the University of California - San Diego

Bee-Harming Pesticides are Declining at Plant Nurseries, Report Shows

Los Angeles Times - Business Section   By Geoffrey Mohan  August 17, 2016

A honeybee works on an almond blossom on a farm south of Fresno. (Rich Pedroncelli / Associated Press)Retailers appear to be selling fewer ornamental plants laced with pesticides linked to bee population declines, according to a new report.

Less than a quarter of the trees and flowers from stores and nurseries tested by environmental activists contained pesticides at levels that could be harmful to bees, which are vital to pollinating many of the nation’s food crops. Two previous reports, in 2013 and 2014, revealed that more than half of the samples contained potentially dangerous levels of chemicals linked to bee deaths.

“Our data indicates that compared to two years ago, fewer nurseries and garden stores are selling plants pre-treated with systemic neonicotinoid insecticides,” said Susan Kegley, a chemist at the Pesticide Research Institute and lead author of the report released Tuesday by the institute and Friends of the Earth.

Neonicotinoids, which mimic nicotine insecticides produced naturally in leafy plants, have been linked to the decline of bee populations. 

In January, the U.S. Environmental Protection Agency said one such chemical, imidacloprid, “potentially poses risk to hives when the pesticide comes in contact with certain crops that attract pollinators.” Imidacloprid is found in at least 188 farm and household products in California.

Activists hailed recent pledges by such major retailers as Home Depot and Lowe’s to phase out neonicotinoids in the plants they purchase from nurseries, even as they urged others, such as Wal-Mart and True Value, to make similar moves. About 65 retailers, including Whole Foods and BJ’s Wholesale Club, have committed to phasing out neonicotinoid-treated plants, according to the report.

The pesticides are predominantly used to control sucking insects, such as aphids and psyllids, that damage the plants.

“The market is shifting away from selling bee-killing pesticides, and retailers including Ace Hardware and True Value are lagging behind their competitors,” said Tiffany Finck-Haynes, food futures campaigner with Friends of the Earth.

Jean Niemi, a spokeswoman for True Value Co., said the company is willing to phase out neonicotinoids when “suitable alternatives become commercially available.” In a letter sent to Friends of the Earth last year, the company said such a phase-out would occur over a three-year period.

A Wal-Mart spokesman said the company “has been monitoring the science around neonicotinoids” and bee health and will rely on the U.S. Environmental Protection Agency to assess the hazard posed by exposure to the chemicals.

A spokesman for Bayer CropScience, the primary manufacturer of Imidacloprid, said there is no evidence that proper use of neonicotinoids on home and garden products harms bees, and cautioned that losing home vegetation to insect damage can decrease habitat for the pollinators.

“Over its 20-year history, there has not been a single documented honey bee colony loss that can be attributed to a labeled use of imidacloprid,” said Bayer CropScience spokesman Jeff Donald.

“The unfortunate effect of the activists’ campaign is consumers who lose choice on how to protect their lawn and gardens, which may result in them losing plants and flowers to damaging pests or in them resorting to other costly or potentially more dangerous pest control measures,” Donald added.

Of the 60 samples taken nationwide — including several in the Bay Area and Sacramento — 14 showed traces of one or more neonicotinoid pesticides, mostly imidacloprid.  

Three of 13 samples from city-owned landscaping also tested positive. Most of the samples that tested positive contained one pesticide; two flower samples contained two different neonicotinoid insecticides, according to the report.

California’s $7-billion almond industry depends almost completely on pollination services provided by bees. Other crops that depend strongly on commercial honeybee colonies include alfalfa, apples, avocados, blueberries, cherries, cucumbers, onions, cantaloupe, cranberries, pumpkins and sunflowers.

California farmers applied nearly 144 tons of imidacloprid on more than 1.5 million acres in 2013, the last year for which complete data were available, according to the state Department of Pesticide Regulation.

The top users of the pesticide were wine-grape growers, who applied 30 tons of it to about 240,000 acres in 2013, according to the state agency. Growers of table and raisin grapes, tomatoes for processing, oranges and cotton also were among the heaviest agricultural users, according to the agency.

The single biggest user, however, was the predominantly urban pest-control industry, which applied nearly 37 tons to homes and businesses to combat pests such as termites, according to the agency.

Several studies have linked high levels of neonicotinoids to decreased foraging, failures of queen bees, breakdowns in hive communication and other colony-threatening phenomena. Last year, however, a study suggested that exposure to levels of the pesticide expected on most farms would pose no significant negative effects on bee colonies.

Many factors have been blamed for the bee die-offs: exposure to multiple pesticides, poor hive management practices, loss of habitat and natural pathogens such as mites and viruses. The USDA last year reported winter colony losses of about 23%, based on a survey of beekeepers. A winter decline of about 19% is considered normal.

In May, the USDA reported a 17% loss of colonies from commercial beekeepers during the first quarter of this year. About 114,000 colonies were lost in a manner suggesting colony collapse disorder in that period, the USDA reported. That same quarter a year ago showed 92,300 colonies lost under similar circumstances.

Bayer Concurs With EPA Findings on Certain Neonicotinoid Hazards to Honey Bees

Beyond Pesticides   January 14, 2016 

Bayer CropScience, revising its stance, has decided to concur with the Environmental Protection Agency’s (EPA) preliminary risk assessment of neonicotinoids and acknowledge the finding of harm to honey bees in certain crops. A spokesman for Bayer CropScience said the neonic-selling giant has reviewed the assessment and found it to be “quite good and scientifically sound,” according to a news report. The Guardian is reporting that Bayer will be proposing new protections for pollinators, however the company has not yet announced what the new protections will be. This is a stark turnaround from Bayer’s statement last week, which said EPA’s assessment “appears to overestimate the potential for harmful exposures in certain crops, such as citrus and cotton, while ignoring the important benefits these products provide and management practices to protect bees.”

Last week, EPA released its preliminary honey bee risk assessment for one of the most widely used neonicotinoids, imidacloprid, which is linked to...

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Source: The Guardian

Providing Help for Hurting Pollinators By Rhonda Brooks, Farm Journal Seeds & Production Editor July 26, 2014

Complex problems are rarely, if ever, solved by simple answers. The alarming loss of honey- bees in North America during the past few years is no exception.

One encouraging sign, however, is that stakeholders, including farmers, beekeepers and the crop protection industry, are addressing the problem and looking for ways to solve it. 

"We want everyone to have some skin in the game," says Laurie Adams, executive director of the Pollinator Partnership, an organization intent on finding ways to address the loss of pollinators and encouraging all stakeholders to participate in the process.  

In early 2013, the USDA–Natural Resources Conservation Service stated it will provide close to $3 million in technical and financial assistance for interested farmers and ranchers to improve the health of bees. The focused investment to improve pollinator health will be targeted in Minnesota, North Dakota, South Dakota, Michigan and Wisconsin. 

Honeybee pollination supports an estimated $15 billion worth of agricultural production or as much as one-third of all food production, including more than 130 fruits and vegetables such as almonds, blueberries and cantaloupe. 

What’s at stake. Bee die-offs in North America have occurred at an alarming rate in recent years. Preliminary results from the 2013-14 survey by the Bee Informed Partnership, funded by USDA, show losses of managed honeybee colonies have averaged 30.5% for the past eight years.  

A report issued by USDA and the Environmental Protection Agency (EPA) this spring cited a complex list of contributing factors: habitat loss, poor diet, declining genetic diversity, diseases, parasites and pesticide exposure.  

"The neonicotinoids are the main target for beekeepers and environmental groups," says Don Parker, integrated pest management manager for the National Cotton Council. "They’re going after these materials hard."  

bee 1Some scientists contend that contaminated dust from corn seed and other crops treated with neonicotinoid-based insecticides, talc or graphite is a contributing factor in die-offs. The theory claims bees are exposed to the dust when they land on dandelions and other flowering plants, and then they carry the dust back to the colony. 

Parker says EPA has found no evidence of "imminent hazard" to honeybees or other pollinators. 

Canadian farmers were mandated to use Bayer CropScience’s new Fluency Agent this past spring when planting neonicotinoid-treated seed. Use of the product was not required in the U.S.

For the past eight years, overwinter colony loss has averaged 30% from Oct. 1 to April 1. 

The product reduces the amount of insecticide active ingredient released in seed dust during planting therefore reducing risk of exposure to non-target insects, such as bees and other pollinators says Kerry Grossweiler, manager of equipment and coatings, SeedGrowth, Bayer CropScience.

honeybees with comb

Using best management practices, such as cleaning treatment residues off equipment away from fields, using the recommended rate of lubricants and growing strips of native perennial plants around fields to improve habitat, can help preserve pollinators.  
FEATURED IN: Farm Journal - Seed Guide 2014