Continued applications of the most widely used insecticides in the world must be urgently restricted, say 233 scientists in a tightly argued letter published in the journal Science.
The scientists, led by Davie Goulson from the University of Sussex in the UK, say that neonicotinoids – a family of neuro-active insecticides first developed in the 1980s – represent a clear and present danger to the survival of numerous species of pollinators and pest-predators that are of “vital importance” to humanity.
The insecticides have been linked to colony collapse disorder in bees, which is resulting in a precipitate decline of pollinators essential for much modern agriculture.
In a literature review published last year, Goulson and colleague entomologist Thomas Wood of Michigan State University in the US revealed that only around 5% of the water-soluble active ingredients in applied neonicotinoid insecticides are taken up by target plants. The rest disperses into the wider environment, fuelling fears that it is adversely affecting a wide range of other insects.
Neonicotinoids in the food chain also move upwards as well as sideways. A study, also published in 2017, analysed 198 honey samples from across the world. The insecticides – sometimes up to five varieties at once – were found in 75% of them, albeit at a level below the maximum exposure considered safe for humans.
In April this year, the European Parliament voted to institute a complete ban on the outdoor use of three of the most popular neonicotinoids. In 2017, the Canadian province of Ontario also moved to partially restrict their use.
To date, however, no other governments have made similar moves – a degree of inaction which prompted Goulson and 232 other signatories to draft the letter.
“Failure to respond urgently to this issue risks not only the continued decline in abundance and diversity of many beneficial insects, but also the loss of the services they provide and a substantial fraction of the biodiversity heritage of future generations,” they warn.