I must admit, especially during the early days of campaigning, I tended to lump the terms for ‘insecticide’ and ‘pesticide’ together, but I think it’s important, for the sake of comprehension of this study, to provide a little clarity here:
Pesticide is a term which relates to substances used to control crop 'pests', whether they be invertebrates, ‘weeds’ or plant diseases.
The term ‘pesticide’ therefore includes
- insecticides – for killing insect pests
- molluscicides – for killing molluscs or gastropods, especially slugs and snails
- herbicides – for controlling ‘weeds’
- fungicides – for plant fungal diseases.
The following field study finds that even when pollen is collected from primarily non-target crops (i.e. the crop selected for treatment by the farmer), the contaminated pollen collected nevertheless exposes honey bees to a level of risk outside of regulatory boundaries.
It also finds that the risk is coming specifically from insecticides – even when the crop (in this case, apples) were not treated that particular season (note that some of these poisons – such as neonicotinoids, are persistent, meaning that they remain in soil some years after initial treatment).
A link to the study is provided at the bottom of this article.
Authors: Scott H. McArt, Ashley A. Fersch, Nelson J. Milano, Lauren L. Truitt & Katalin Böröczky
Published: Nature.com, Scientific Reports 7, Article number: 46554 (2017); doi:10.1038/srep46554 Published online:19 April 2017
The scientists conducted a field test, using a network of 120 experimental honey bee colonies placed in 30 commercial (and pesticide- treated) apple orchards in western and central New York.
Simple summary of findings and research:
The researchers had set out to answer three related questions:
(1) How does landscape context govern focal crop foraging by honey bees during pollination of apple, a mass-blooming commercial crop?
(2) Is focal crop pollen foraging related to pesticide residues in recently accumulated beebread and/or pesticide risk, as measured by the Pesticide Use Index (PUI) and Pollen Hazard Quotient (PHQ), and
(3) Given different on-farm pest management practices and landscape context surrounding farms, when do these factors lead to substantial pesticide risk to bees?
Pesticide residues in bee-collected pollen
can be high despite non-crop sources accounting for the majority of pollen.
The scientists propose that the results suggest:
The scientists investigated whether the levels of pesticides found in beebread represented a substantial risk to bees. They found that risk from acute contact exposure was above the United States Environmental Protection Agency level of concern at 2 of 30 orchard sites, and above the European Food Safety Authority (EFSA) level of concern at 5 of 30 orchard sites.
They also found that risk from chronic oral exposure was above the EFSA level of concern at 22 of 30 orchards. Thus, the scientists concluded that bees at the majority of the orchard sites, experienced pesticide risk exceeding a regulatory agency-determined level of concern for acute or chronic exposure during the apple bloom period.
Compounds sprayed during bloom but omitted from the residue analysis were either:
9 common pesticides were also quantified, despite not being sprayed during the particular bloom period at the 30 sites.
Among them were 5 insecticides (chlorantraniliprole, clothianidin, cyfluthrin, fenpyroximate, and imidacloprid), 3 fungicides (fluxapyroxad, myclobutanil, boscalid) and 1 herbicide (atrazine).
Overall, 64% of the pesticides they detected in beebread were not sprayed at the respective sites during apple bloom. Because several of these pesticides were highly toxic insecticides, pesticides that were not sprayed during apple bloom accounted for 62% and 66% of contact and oral pesticide risk, respectively, across the 30 sites.
The scientists found that fungicides accounted for 94% of total residues (in ppb) in beebread. However, when they calculated pesticide risk via contact and oral pollen hazard quotients (PHQ), they found that insecticides (more than fungicides) represented the majority of pesticide risk to bees, accounting for 98.4% of contact and 97.7% of oral PHQ.
The study can be viewed by copying and pasting this link into your browser: https://www.nature.com/articles/srep46554
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