Bees could be protected by spraying crops at night, according to new research.
As the sun begins to set, they return home for the evening, greatly reducing mortality because they are absent from the fields.
Appropriate choice of formulation is another way to avoid killing off the vital pollinators.
Many common methods for minimizing impact – even some recommendations on product labels – are backed by little evidence, say scientists.
A review found few mitigation measures had more than one or two studies evaluating effectiveness and design methods varied.
For instance, some tested for direct overspray and others for longer-term residues. Just three evaluated techniques frequently found on pesticide labels.
“Least researched was testing on how you time a pesticide spray, be that time of day or time of year,” Straw said.
Other measures included how pesticides are applied, buffer zones, removing flowering weeds before spraying, moving or covering colonies and administration during specific weather conditions or crop stages.
Most studies focused on repellent additives which encourage bees to avoid a recently sprayed crop.
Several compounds have shown promise in lab experiments, but all 12 looked at honey bees only, and none in combination with a pesticide – just on their own.
Straw and colleagues say stronger testing is needed to evaluate what is truly effective at protecting them and which ones may be too reliant on conventional wisdom.
Growers are urged to follow a variety of ‘mitigation measures’ such as spraying at night, using specific nozzles or maintaining buffer zones.
Just 34 studies matched their criteria, spread across a wide range of measures—but largely focused on just one kind of bee.
Too much hinges on bee-protective measures for them to be weakly supported, said the researchers. Bees play a critical role in both natural ecosystems and agriculture.
The presumption that mitigation measures are effective can be factored into decisions to authorize pesticides for use. Rigorous scientific evaluation of these measures is imperative.
But, if such research can be generated, there’s reason to believe it will have immediate positive impacts.
Earlier this year the same team found compliance with pesticide regulations and guidelines among farmers in an anonymous survey was high.
Previous research has found every square kilometer in the UK has lost an average of 11 species of bee between 1980 and 2013.
Produced in association with SWNS Talker
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