A quick review of the recent paper on pesticide analysis of U.S. beehives. All the following are quotes from the paper [with my comments in brackets]. From Mullin CA, Frazier M, Frazier JL, Ashcraft S, Simonds R, et al. 2010 High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health. PLoS ONE 5(3): e9754 [I have removed some citations for ease of reading] No neonicotinoid residues were found in bees, [although they were rarely found in] pollen and wax. Overall, pyrethroids and organophosphates dominated total wax and bee residues followed by fungicides, systemics, carbamates and herbicides, whereas fungicides prevailed in pollen followed by organophosphates, systemics, pyrethroids, carbamates and herbicides. [The fungicide of most concern is the commonly detected chlorothalanil (Bravo®, Headline®), which has been associated with “entombed pollen.”] Beeswax remains the ultimate sink from the long-term use of the miticides fluvalinate, coumaphos, amitraz and bromopropylate [this is an interesting finding, since this chemical is not registered for use in the U.S.]…. Colony residue levels of these miticides, after their in-hive application, have been shown to increase from honey to pollen to beeswax. Beeswax is the resource of the hive that is least renewable and is thus where persistent pesticides can provide a “toxic-house” syndrome for the bees. The uniform high levels of these miticides present in foundation is particularly disturbing, since replacement of comb is currently recommended to reduce pesticide contaminants. The broad contamination of European foundation with especially miticides has been reviewed previously. Fluvalinate residues in beeswax best correlated with the French bee winter kill of 1999–2000, although disease factors were more emphasized in the report. Almost all wax and pollen samples (98.4%) contained two or more pesticide residues, of which greater than 83% were fluvalinate and coumaphos. Clearly, substantial residues of these bee-toxic pyrethroid and organophosphate compounds prevailed together in most beehives sampled. Chronic exposures to high levels of these persistent neurotoxicants elicits both acute and sublethal reductions in honey bee fitness, especially queens, and they can interact synergistically on bee mortality. Our work does not directly associate these miticides with CCD, although higher coumaphos levels may actually benefit the colony, possibly via mite control Externally-derived, highly-toxic pyrethroids, up to 9 in addition to fluvalinate per sample, were the most frequent and dominant class of insecticides in our samples. Pyrethroids are frequently associated with bee kills. A sample of dead bees, obtained after a community-wide tree application of permethrin according to label instructions, contained 19.6 ppm, 18-times the established bee LD50. Pollen and wax levels of more toxic pyrethroids including bifenthrin, cyfluthrin, cyhalothrin, deltamethrin, and fenpropathrin ranged up to 613 ppb, which is above the bee LD50 for deltamethrin. This level can be lethal depending on pollen consumption rates by differing castes, or wax transfer rates to brood or indirectly to pollen. Moreover, some bee residues of deltamethrin, fenpropathrin and cypermethrin are above levels shown to disorient foragers and cause CCD-like symptoms (see above). It is important to note that pyrethroids are rarely found alone, and in 50% of our pollen and wax samples co-occur with chlorothalonil, a fungicide known to increase bee toxicity of cypermethrin by greater than 5-fold. Bee toxicity of the pyrethroid bifenthrin doubles after Apistan (fluvalinate) treatment, which frequently coincides in our samples. Potential for interactions among multiple pyrethroids and fungicides seems highly likely to impact bee health in ways yet to be determined. Pyrethroids other than fluvalinate have been reported to impact the foraging capabilities of honey bees. After topical application with 0.009 µg permethrin/bee … none of the foraging workers returned to the hive at days end, and only 43% of these bees returned even once to the hive because of disorientation due to the treatment. vanDame et al. found a similar effect on foragers with deltamethrin at 0.0025 µg/bee (25 ppb), a dose 27 time lower than the LD50, which disoriented 91% of return bee flights to the hive. These symptoms are reminiscent of those reported for CCD. Our results do not support sufficient amounts and frequency in pollen of imidacloprid (mean of 3.1 ppb in less than 3% of pollen samples) or the less toxic neonicotinoids thiacloprid and acetamiprid to account for impacts on bee health… [It is surprising to me that the authors bring up the neonicotinoid insecticides some twelve times in the paper, when the most notable chemical in this class, imidacloprid (mentioned thirteen times), was only found in 1.7% of the samples! Note also that there were zero detections of clothianidin, a widely-used neonicotinoid, which has frequently been blamed for colony collapses! For example, the authors state:] Systemic neonicotinoid use has greatly increased recently for treating seeds of many major crops, particularly those genetically-engineered, and considerable impact to non-target species may occur. Neonicotinoids and systemic fungicides are often combined as pest control inputs, and many of the latter synergize the already high bee toxicity of neonicotinoids [Iwasa 2004]. A recent landscape-level study of imidacloprid seed treatments on maize in Belgium demonstrated no impacts on honey bees; however, their high prevalence with EBI and other fungicides including myclobutanil, although refuted by some field results [Schmuck 2003], may have more direct impacts on bee health through synergistic combinations. [I find it of interest here to quote from the papers cited. Iwasa states that three tested synergists had “minimal effect on imidicloprid [toxicity].” He also states that “When honey bees were placed in cages in forced contact with alfalfa treated with acetamiprid and the synergist,triflumizole,in combination at their maximum recommended application rates,no mortality was detected above that of the control.“ The Schmuck paper concludes that “Our results suggest that, at the recommended use rates, thiacloprid poses a negligible lethal risk to honeybees when applied either alone or in tank mixes with fungicides of various chemical classes.”] [As far as the beekeeper-applied miticides are concerned, the authors state that] High levels of fluvalinate and coumaphos are co-occuring with lower but significant levels of 98 other insecticides, fungicides and herbicides in pollen…. Foundation wax is uniformly contaminated with miticides…. Twenty-one wax samples from six different commercial and two private foundation sources were uniformly contaminated with up to 10.1 ppm fluvalinate …and up to 14.3 ppm coumaphos. Extraordinary enhancement of toxicity has been found with addition of commercial synergists to fluvalinate, where a topical LD50 of 0.00964 µg/bee, a 980-fold increase to their reported 9.45 µg/bee without the additive, occurred if 100 µg of piperonyl butoxide [a common pesticide synergist] was applied 1 hr prior to the pyrethroid. [My take on these results is that attention to the neonicotinoid pesticides is largely displaced, whereas we should be focusing on the in-hive miticides, the agricultural pyrethroids, and the fungicides.] Randy Oliver *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html Access BEE-L directly at: http://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A0=BEE-L