Researchers at the University of Neuchâtel measured the concentrations of five neonicotinoid insecticides in 702 soil and plant samples from 169 cultivated fields and 62 Ecological Focus Areas (EFA) across Switzerland’s lowland areas – EFA are areas set aside to improve the environment or climate.
Organic farms, EFAs and organic seeds are supposed to be free of these pesticides. However, traces of least one of the five neonicotinoids were found in 93% of organic soils and crops and in more than 80% of EFA soils and plants. In addition, 14 out of 16 organic seeds tested positive for neonicotinoids.
Neonicotinoid concentrations in the soil of organic farms were much lower than those found in the soil of conventional farms.
Researchers said their findings suggest organic farms are victims of overuse of these pesticides on conventional farms. In addition, they said that the resulting loss of biodiversity could jeopardize organic farming by eliminating natural forms of defense against pests.
Neonicotinoids are a class of neuro-active insecticides chemically similar to nicotine developed in the 80s and 90s. They attack the nervous system causing paralysis and death. Their use has been linked to the collapse of the honey bee population.
In December 2013, the EU restricted the use of three neonicotinoids. Switzerland did the same. In 2018, the restriction was confirmed and extended. These three neonicotinoids were among the five tested by researchers at the University of Neuchâtel.
The agrochemical makers Syngenta and Bayer challenged the EU ruling, and Syngenta demanded compensation of 368 million euros, according to RTS. The EU rejected these demands.
The researchers at the University of Neuchâtel recommend cutting the use of all of these agrochemicals to protect insects and biodiversity.
Summary of the research (in English)