Grave concerns about novel pesticides after 100% mortality rates

Mason bees die after exposure to new pesticide replacement

By Annette J Beveridge

The negative impact of pesticides on bees and other pollinators is well documented, yet even so, new pesticide replacements are still being licenced. A new study reveals the serious implications of this.

Lethal results

The new pesticide considered to be a potential successor for the previously banned neonicotinoids has been found to cause 100% mortality in Mason bees.

Flupyradifurone was believed to reduce risks for pollinators and was subsequently licenced on a global scale for bee-visited crops. Recent research by scientists at the University of Bristol and the University of Texas at Austin discovered that despite the positive expectations it was lethal for the bees (Osmia lignaria) which were exposed to pesticide-treated wildflowers.

Ongoing implications

The study revealed other consequences.

Bees released onto the plants seven days later were less likely to start nesting. The survival rates of those bees were lower too and there was less efficiency with foraging.

On average, the bees took 12.78% longer to collect pollen and nectar.

Lead author Harry Siviter from Bristol's School of Biological Sciences said: "These results demonstrate that exposure to flupyradifurone poses a significant risk to important pollinators and can have negative impacts on wild bees at field-realistic concentrations."

There are significant negative impacts on pollinators through the use of neonicotinoid pesticides and these have led to high profile restrictions in the usage across the EU as well as other regions and it is this that increased the demand for these knew insecticides.

Siviter said: “There is an urgent need to evaluate potential replacement crop treatments.

"These results caution against the use of novel insecticides as a direct replacement for neonicotinoids.

"Our findings add to a growing body of evidence demonstrating that pesticide risk assessments do not sufficiently protect wild bees from the negative consequences of pesticide use."

Breaking the cycle

This latest research reveals the need to break the cycle of novel pesticide release and removal.

Siviter said: "Restricting the use of commercial pesticides containing flupyradifurone to non-flowering crops would be sensible while more research is conducted.

"In the long-term, as we are already seeing in the EU, a move towards a more holistic approach to risk assessment that considers the biology of non-Apis bees is required to better protect pollinators from the unintended negative impacts of pesticides."

There is now the intention for the team to extend their research and to measure the impact of exposure through soil on solitary bees.