Rapeseed is a major cash crop in the UK and elsewhere in Europe, so when you see those familiar strips of yellow in the late spring – think profits for farmers. Rapeseed is heavily treated with insecticides and fungicides – so also think profits for agrochemical companies. One of these insecticides, the improbably named Cruiser OSR, is a big earner for the agrochemical company Syngenta. In a surprise move last week, the French Minister of Agriculture has issued a warning that he intends to revoke the licence for Cruiser OSR. This story has hardly featured in the UK press but it has considerable significance.
One of the active ingredients in Cruiser OSR is thiamethoxam, a member of the class of neonicotinoid insecticides that act by poisoning the nervous system of insect pests. These insecticides are used either as seed dressing or as systemic treatments. Either way the compound is present throughout the plant and available to kill insect pests.
Not all insects are pests, however. Bees perform a crucial role in pollinating crops and without bees food would be much more expensive and the countryside would look very different. Evidence has been accumulating that, as well as killing insect pests, the neonicotinoid insecticides can have harmful effects on bees. In crops treated with these insecticides the harmful chemical is present throughout the plant and may be picked up by bees when they forage for pollen or nectar. Rapeseed, for example, provides an important source of food for bees when they emerge after winter. If the crop has been treated with Cruiser OSR then it is likely that bees will feed on contaminated pollen and nectar and may pick up the thiamethoxam.
In Italy it was found that when maize seed coated with the insecticide imidacloprid (another neonicotinoid) began to be used there were bee deaths coincident with sowing. Most likely, dust from the treated seeds was contaminating land used by bees. When the use of neonicotinoid-coated maize seed was banned in Italy these bee deaths did not occur. France and Germany have joined Italy in banning the use of some neonicotinoids as seed dressing also because of effects on bees.
The agrochemical companies claim that these insecticides are safe for bees if used properly but new research published earlier this year showed that under field conditions and at sub-lethal doses, the neonicotinoids can have serious effects on the ability of bees to navigate and may affect the survival of bee colonies. The response of DEFRA in this country was as follows: “We have considered all recently published studies and have concluded that they do not present any new evidence”.
In France, the response has been different. The National Agency for Safety of Food and the Environment (ANSES) was asked to report on the significance of the new work. ANSES concluded that the new studies did provide evidence of a threat and the Minister acted accordingly.
Syngenta has responded to the proposed ban on Cruiser OSR: “This is a dark day for French and European agriculture – 30% of rapeseed will be lost”
Bees are under pressure from many influences including loss of habitat, climate change, hive pathogens and insecticides. If France considers these insecticides to pose a threat to bees, I do hope DEFRA will now reconsider the effects of these compounds on bees in the UK.