It’s not just the bees and their ilk. Neonicotinoid insecticides were known to harm important pollinators, and now a major report says they are killing insects, microbes, lizards, earthworms, birds and even coastal shellfish.

Neonicotinoids make up almost one-third of insecticides used. In 2011 the International Union for Conservation of Nature set up a task force to review the safety of systemic pesticides. After reviewing over 800 studies the group now says present use “is not sustainable”, and calls for a global phase-out.

The chemicals break down more slowly than early tests suggested, says author Jeroen van der Sluijs of Utrecht University in the Netherlands. These past studies, which informed the decision to allow the use of neonicotinoids, looked mostly at immediate effects. But long-term environmental build-up may be the real problem, so the task force says the previous regulatory studies “lack environmental relevance”.

The European Union has imposed a two-year moratorium on neonicotinoids, but their half-life in soil can be three years, so this may be too little to see what happens when they are gone.


The group found that levels of neonicotinoids in water often exceeded legal limits in both North America and Europe. Even in non-treated fields, the neonicotinoids and their breakdown products were harming many creatures. That includes bacteria, amoebae, worms and insects in soils; pollinators such as hoverflies and butterflies; and even lizards, because the termites they eat are dying. “What really surprised me is that these chemicals are even harming coastal organisms like crabs and shellfish,” says van der Sluijs.

The impacts on soil organisms could affect the whole nutrient recycling process, says van der Sluijs. Even when levels are too low to kill, the neural toxicity of neonicotinoids impairs earthworms’ ability to tunnel and feed.