15 November 2022
Today, the Bumblebee Conservation Trust has published a new evidence-based position statement on the impacts that pesticides can have on bumblebees. We have set out five key recommendations to help policy makers, local authorities, businesses and individuals reduce the negative impacts that pesticides can have on bumblebees and other non-target animals. In most situations this means not using pesticides at all. A summary of the statement is included below.
What are pesticides and how do they impact bumblebees?
Pesticides are substances (both synthetic and natural) used as treatment against unwanted insects (insecticides), plants (herbicides), fungi (fungicides), or other groups. These treatments are applied in multiple ways and for many reasons, including food production, forestry, amenity use and in private gardens. They can negatively impact bumblebees in a number of ways:
- Direct impacts – lethality and sub-lethal effects – Insecticides kill insects, including bumblebees, when they are exposed to a lethal dosage. Exposure at lower levels can lead to sub-lethal effects, which impact on the fitness of individual bumblebees, colony fitness and their ability to reproduce. Exposure to pesticides can exacerbate the effects of other stressors like food shortages and disease and can also impact crop pollination.
- Indirect effects – Herbicides are used to kill the flowers that bumblebees need to survive. Killing off flowering plants, including volunteer wildflowers (‘weeds’ such as dandelions, clovers, etc.), leaves bumblebees and other pollinators with food shortages. The widespread loss of flower-rich areas from our countryside is recognised as the leading driver of pollinator declines in the UK.
- The cocktail effect – Bumblebees are exposed to multiple different chemicals throughout their lives. Pesticides and other chemicals can work together in unexpected ways that increase the harm they can cause, but are rarely tested together, even when used as part of the same formulation. Some non-active ingredients of commonly used herbicide and fungicide products have recently been found to have lethal effects in bumblebees.
What needs to change?
We need action to phase out municipal and domestic use of pesticides entirely. To produce food sustainably, we need to wean ourselves off pesticides, which harm ecosystem services like pollination and natural pest control, and contribute considerable greenhouse gas emissions during both creation and use.
- Race to the top, not the bottom – Pesticide use regulations within the UK are currently largely synchronised with the EU, but Brexit means these may now diverge. It is imperative that Britain’s bumblebees should not lose protection because of this. Any advances in protection in the EU should be at least mirrored in the UK. Pesticide regulations should also form part of trade negotiations to avoid the risk of the UK government making new trade deals with countries with less stringent pesticide regulations and exporting harm to ecosystems abroad.
- Ensure testing is representative of wild bee communities – Current testing of new pesticides on bumblebees is limited to – at best – oral and contact exposure in Buff-tail bumblebee workers, while no testing is carried out on solitary bees. More extensive testing is done on honeybees and extrapolated to wild bees, despite big differences in biology and life-history. We need to go beyond only testing active ingredients in isolation to avoid harmful cocktail effects that bumblebees experience in the real world.
- Show pesticides the yellow card – By following the medical industry’s ‘yellow card’ system, which openly logs and investigates harms after medical interventions or interactions between treatments and other causes, real-world harms caused by authorised pesticides can be identified. This would allow detection of long-term harms, which can be almost impossible to find with pre-authorisation testing alone, including those caused by the cocktail effect.
- Reduce pesticide use through nature-based solutions and integrated pest management – Building natural resilience into the farmed environment (including agriculture, horticulture, & forestry) is key to reducing our need for pesticides. Integrated pest management (IPM) means working with nature to boost natural pest-control and adopting the least environmentally damaging option to deal with pests that go beyond set tolerance thresholds. Governments must develop effective ways of incentivising a meaningful shift towards IPM principles and away from pesticide use as a first resort, including committing to an ambitious pesticide-use reduction target.
- End pesticide use in domestic and urban settings – The use of pesticides in gardens, playing fields, parks and elsewhere across the unfarmed landscape is unsustainable and poses an unnecessary risk to bumblebees and other pollinators. The best alternative is to increase tolerance for ‘weed’ species and to allow more wildflowers to grow within the urban environment. We are calling for governments of all scales, retailers and individuals to phase out these uses of pesticides entirely and seek sustainable alternatives.
