Bee Hives Harbor 70 Different Pesticides

In a presentation today at the National American Chemical Society in Philadelphia, Penn State researchers Maryann Frazier, Senior Extension Associate, James Frazier, insect physiologist, Sara Ashcraft, research assistant, and Chris Mullen, insect toxicologist told about the many pesticides found in samples of adult bees and brood, pollen and wax collected from honey bee colonies suspected to have died from apparent symptoms of Colony Collapse Disorder.

The results show unprecedented levels of fluvalinate and coumaphos -- pesticides used by beekeepers in the hives to combat varroa mites -- in all comb and foundation wax samples. They found lower levels of 70 other pesticides and metabolites of those pesticides in pollen and bees.

While the chemicals used to control varroa were expected, the other pesticides’ levels were also surprising. Every bee tested showed at least one pesticide, and pollen averaged six pesticides with as many as 31 in a sample. "It was a bit of a shock to see the levels and the widespread presence of these pesticides," said Maryann Frazier.

"We already had in place ways to test for viruses, bacteria and fungi, but it was difficult to find an analytical laboratory that could analyze for unknown pesticides”, said Mullin. “We need to look at all pesticides, not just those used in beekeeping," he said.

Eventually, samples were sent to the National Science Laboratory of the USDA Marketing Service that tests other commodities such as milk, fruits and vegetables.

We looked for over 170 pesticides using a modified QuEChERS (Quick, Rugged, and Safe), along with gas and liquid chromatography to analyze the pollen, bees and wax. The techniques uses only a three gram sample and generates results at the parts per billion range.

Beeswax foundation, used by beekeepers to organize a hive for the bees, was found to contain pesticides also, but the researchers were able to reduce the levels of pesticides in these sheets of beeswax by subjecting them to gamma irradiation.

Beekeepers can control pesticide use in their beehives and this report points out that this indeed is a necessary management activity. This includes using fewer, safer chemicals that do not build up in beeswax like the volatile essential oil treatments that are available. Trapping varroa mites in their colonies using drone comb is also helpful, but both of these techniques are time consuming and expensive. But replacing beeswax combs in their hives on an annual or every-other-year basis at most is also necessary, and this, too is expensive. The choices, at the moment are slim for beekeepers ... control varroa or your colony dies, but if you use the most efficient means to control them -- harsh chemicals -- is as, if not more, expensive than wax replacement.

But the researchers found more.

The Net Effect: Who Knows?

“We are finding fungicides that function by inhibiting the steroid metabolism in the fungal disease they target, but these chemicals also affect similar enzymes in other organisms,” Said James Frazier. “These fungicides, in combination with pyrethroids and/or neonictotinoids can sometimes have a synergistic effect hundreds of time more toxic than any of the pesticides individually.” The EPA only looks at acute exposure to individual pesticides, but chronic exposure may cause behavioral changes that are unmonitored. Yet, a North Carolina study found that some neonicotinoids in combination with certain fungicides, synergized to increase the toxicity of the neonicotinoid to honey bees over 1,000 fold in lab studies. In another report released earlier this year by Maryann Frazier, additional information comes to light, parts of which are related below:

In an EPA fact sheet on Clothianidin, a commonly used neonicotinoid pesticide, it was disclosed that this chemical has the potential for toxic chronic exposure to honey bees through the translocation of clothianidin residues in nectar and pollen. In honey bees the affects of this toxic chronic exposure may include lethal and/or sub-lethal effects in the larvae and reproductive effects on the queen. Documented sublethal effects of the neonicotinoids include physiological affects that impact enzyme activity leading to impairment of olfaction memory, motor activities that impact navigation and orientation and feeding behavior, and memory impairment and brain metabolism, particularly in the area of the brain that is used for making memories. When used as a seed treatment the chemical was present, by systemic uptake in corn and sunflowers in levels high enough to pose a threat to honey bees. In a 2002 survey for pesticide residues in pollen in France, Imidacloprid was the most frequently found insecticide and was found in 49% of the 81 samples taken.

Bayer CropScience, in a 2007 FAQ on Neonicotinoid insecticides they produce discredit much of the information presented with research of their own. Long-term chronic exposures do NOT (emphasis Bayer’s) represent a significantly greater risk than acute exposures because these chemicals are rapidly metabolized and do not bio-accumulate. Disorientation and memory function, and effects on queen and brood development at the 20 parts per billion sublethal dose (more than 20 ppb is considered a lethal exposure) posed no problems said Bayer. The fungicide/insecticide relationship was monitored by Bayer, but “this synergistic effect has only been demonstrated to occur under highly artificial laboratory conditions. In field trials there was no evidence of synergistic toxicity to honey bees.”

So ... chemicals do exist in beehives. Some brought there by beekeepers, some by the bees from the outside world. Tiny, tiny amounts of them for sure, but all of them are bad for bees. There are ways to mitigate some of the problems and beekeepers can change their management practices to reduce or eliminate their contributions. However, the continued exposure of honey bees to legally applied pesticides in the outside world has not gone away, and the law, and the logic of continuing to let this situation exist baffles almost everybody who has looked at the problem.