US report cites varroa mite as major factor in bee decline
US authorities have published a report concluding ‘multiple factors’ are to blame for the decline in global bee populations.
The report by the US Department of Agriculture (USDA) and the US Environmental Protection Agency (EPA) concludes the parasitic varroa mite is ‘recognised as the major factor underlying colony loss in the US and other countries’.
It highlights various other factors, including disease, genetics, poor nutrition and pesticide exposure.
In contrast to the recent European decision to suspend three neonicotinoid seed treatments on the basis of a risk assessment by the EU food safety authorities, the US report concludes additional research is needed to determine the risks presented by pesticides.
Whereas the EU decision was based partly on estimates of field exposure based on research in laboratories, the US report concluded: “The most pressing pesticide research questions relate to determining actual pesticide exposures and effects of pesticides to bees in the field and the potential for impacts on bee health and productivity of whole honey bee colonies.”
The report echoes the conclusion of a conference on the impact of agriculture on insect populations that bee decline was a ‘multi-factorial issue’, with more research needed on the impact neonicotinoids in the field. When a panel of experts was asked to list what they believed were the main factors behind bee decline globally, none mentioned pesticides.
Syngenta, which stands to lose its Cruiser OSR treatment under the EU suspension, welcomed the US report.
Syngenta spokesman Luke Gibbs said: “The US assessment and approach is a long way from where the EU started on this issue. The key difference is the USDA has looked at this issue in detail on a scientific rather than political basis.”
A separate report, commissioned by Friends of the Earth, cited intensive farming and urban development as the main reasons behind bee decline.
Researchers from the University of Reading found some of the UK’s most iconic bees are in decline from Scotland to South West England, including the Great Yellow Bumblebee and the Bilberry Bumblebee, probably due to the loss of its vital food plant, wild bilberry.
The report, published on Thursday, concedes banning neonicotinoid seed treatments will not solve the problem ‘without further immediate action to deal with all its causes’.