Pesticide contamination of beeswax from managed honey bee colonies in New York State

The New York State (NYS) beekeeping industry generated >$11M worth of honey in 2020 and >$300M in pollination services to agriculture annually. Bees are frequently exposed to pesticides through foraging and husbandry practices. Lipophilic pesticides can remain in beeswax for extended periods. We analyzed for pesticides in wax comb samples collected from NYS apiaries at the end of the growing season, comparing residue numbers and concentrations among beekeepers of different operation scales: commercial beekeepers (>300 colonies), sideliners (50-299 colonies), and hobbyists (<50 colonies). We analyzed samples collected from 72 managed honey bee colonies for 92 insecticides, herbicides, and fungicides by liquid chromatography-tandem mass spectrometry. Pesticides were detected in all samples and included 34 fungicides, 33 insecticides, and 22 herbicides. Each wax sample contained 7-35 different residues (x¯ = 17.8 residues). Wax from colonies managed by commercial beekeepers contained the most residues (x¯ = 21.9 residues), hobbyists were second (x¯ = 16.3 residues), and sideliners had the fewest (x¯ = 11.7 residues). Nearly all wax samples (98.6%) contained the pesticide synergist piperonyl butoxide, most samples (86%) contained common varroacides used to control honey bee parasites, including coumaphos and amitraz breakdown products, and 93.1% contained the fungicide difenoconazole. We detected 34 fungicides, 7 of which were found in 50% or more of the samples. We detected 22 herbicides. We found pesticide contamination of beeswax to be common, with commercial beekeepers experiencing the greatest contamination.