Yesterday I saw two papers on neonicotinoids and bees. They are the first large scale look at how these systemic pesticides affect bees in the field.
We’ve known for some time that neonicotinoids have bad effects on bees in the lab, which is hardly surprising. They are pesticides, after all. The big argument has been about how they affect bees in the real world.
The Centre of Ecology and Hydrology (CEH) looked at honeybees, bumblebees and solitary bees. Their paper aimed “to quantify the impact… of two commercial neonicotinoid-based seed treatments in commercially grown crops of oilseed rape”. As usual, the results the results have thrown up more questions. People will continue to argue about methodology, I’m sure. In essence, however, the conclusion is that the neonicotinoids harmed both “wild bees” and honeybees.
Ironically, Syngenta and Bayer funded the study. It was their neonicotinoids which were used. Led by the unfortunately named Dr Schmuck, Bayer CropScience are now scrambling to re-interpret the results and are adamant they are not conclusive.
A second paper, however, published in Canada, reached similar conclusions. It looked at neonicotinoid treated maize and honeybees. It has more bad news, as Buglife point out:
The Canadian study also found that the common fungicide boscalid almost doubled the toxicity of neonicotinoids to bees. This is significant because a recent paper showed that 70% of the plants that people buy from garden centres to help garden bees contain neonicotinoids, and 48% also contain boscalid (Lentola et al. 2017). This suggests that gardeners may be unknowingly poisoning pollinators in their efforts to try to help them, a factor that may be associated with recent declines in numbers of urban butterflies (Dennis et al. 2017).
We knew how toxic the combination of insecticides and fungicides is to bee colonies. This first came up when scientists were looking at Colony Collapse Disorder in the U.S. Now we can worry about the scale of the problem.
Three things have continued to irk me throughout this shambles. Firstly, we still know nothing about how these pesticides affect other pollinators. Secondly, what are the less damaging alternatives to neonicotinoids? Farmers claim they would have to use lots more pyrethroid based pesticides to control, for example, flea beetle. Conservationists claim they wouldn’t.* Why is this debate STILL going on? Let’s have some fact based policy! And this take us to the third point. Why have we been using these pesticides for so long without knowing what damage they might be doing? We are supposed to follow the Precautionary Principle. Instead, we seem to chase short term financial gain. Our environment is too precious to turn it into a kind of giant chemical experiment.
*no prizes for guessing where I stand on this one.