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Unlisted RoundUp Ingredients May Be More Toxic to Bumblebees Than Glyphosate

By Mary Wilson

A recent study published in the Journal of Applied Ecology by researchers at Royal Holloway University of London found that several RoundUp formulations are toxic to bumblebees. We generally associate the name RoundUp with the active ingredient, glyphosate, but there are a number of RoundUp formulations, with varying percentages of glyphosate, including at least one with no glyphosate. This study tested three RoundUp formulations and a competitor product called Weedol. Label recommended pesticide concentrations were applied to the bees using a spray bottle. Products were sprayed directly onto more than 50 bees of a bumblebee species common in Europe. The results of the study are tabulated as follows:

Product % Glyphosate % Mortality

RoundUp Ready to Use 41% 94%

RoundUp ProActive 36% 30%

RoundUp No Glyphosate 0% 96%

Weedol 15% 0%

Surprisingly, there was no correlation between percent glyphosate and toxicity. The toxicity then must be related to the balance of the formulation, one or more co-formulants, designed to make the product more effective. Manufacturers are not required to publish the names of these co-formulants. Thus testing results and warnings on product labels are not representative of real world conditions. Some co-formulants are compounds which help the sprayed herbicide to better adhere to the plant surface. Others are compounds which make the active ingredient even more toxic. But since no labeling of any additional components is required, the consumer has no idea what is being purchased and what the associated risks might be.

Is Glyphosate by Itself OK?

Since in this case, glyphosate is not the “bad guy”, some might think that glyphosate by itself is an acceptable herbicide for commercial and household use. However, glyphosate poses many risks including human health concerns, antibiotic effects on soil bacteria and human gut micobiota, degradation of the soil, and loss of habitat for pollinators.

What Should Be Done?

Test results demonstrate that co-formulants and formulations as well as active ingredients should be tested and regulated individually. We suggest that the necessity to properly test pesticide effects on wildlife outweighs company rights to withhold proprietary information.

Testing protocols for gyphosate-based products should include testing on bees. This has never been required as herbicides have been viewed as not having an effect on things other than plant species. Newer studies have shown this is not necessarily true.

Proper testing and labeling should be required on all glyphosate products. It is concerning that there are many glyphosate products on the U.S. market, none of which has labeling with information about any ingredients other than glyphosate. And since testing of the whole product has not been made available, it is impossible to tell which ones might contain chemicals harmful to pollinators. What we do know of course, is that any glyphosate product carries with it some risks to consumers and the environment at large.

Government regulation which would provide for corporate transparency on behalf of consumers, pollinators and the environment is sorely needed.

Mary Wilson


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