In a not widely noticed scientific opinion delivered just before Christmas, EFSA said two neonicotinoid insecticides, acetamiprid and imidacloprid may affect the development of the human nervous system and proposed that some guidance levels for acceptable exposure be lowered while research to determine their developmental neurotoxicity (DNT) continues.

At the request of the European Commission, EFSA's panel on Plant Protection Products and their Residues (PPR) studied the two pesticide ingredients and found that they may affect development of neurons and brain structures associated with functions such as learning and memory.

Based on the panel's review, EFSA has proposed that toxicological reference values for acetamiprid and imidacloprid be lowered to 0.025 and 0.06 micrograms per kilo of body weight respectively and recommended that DNT studies be submitted as part of the EU authorization process for new pesticides.

A two-year moratorium on use of the neonicotinoid class of insecticides including the active ingredients clothianidin, imidacloprid and thiamethoxam - excepting crops unattractive to bees - was imposed by the EU from the beginning of December in an effort to determine whether they contribute to the phenomenon known as Colony Collapse Disorder (CCD).

Researchers in the UK have expressed concern that the EU's bans on neonicotinoids could increase the use of other types of pesticides such as pyrethroids, which they say has been shown to stunt the growth of worker bumblebee larvae, causing them to hatch out reduced in size. "This," said Gemma Baron, a researcher at the University of London, "is of concern as the size of workers produced in the field is likely to be a key component of colony success."

Germany's agricultural chemicals manufacturers organized in the association Industrieverband Agrar (IVA) meanwhile have said they fear a sharp decrease in earnings due to EU restrictions on pesticides. Due to restrictions in place since 2009, the organization said only a quarter of the products currently authorized for use will still be in the market at the end of the decade. It added that the income loss could not be compensated through new products as it takes around ten years to develop new products.