The European Union on Tuesday restricted the use of the insecticide Fipronil, the latest move to protect honey bees after a May ban on three other insecticides.

The ban on the insecticide produced by Germany's BASF was agreed by 23 of the 28 EU states, with only Spain and Romania voting against, EU sources said.

A scientific risk assessment carried out by the European Food Safety Authority (EFSA) in May said seeds treated with pesticides containing Fipronil pose an acute risk to Europe's honey bee population.

The restrictions, to apply from December 31, will ban the use of Fipronil on maize and sunflower seeds but may allow its use for the treatment of seeds that will only be sown in greenhouses.

That exception will not apply to leeks, shallots, onions and vegetables such as Brussels sprouts, cauliflower or broccoli.

BASF criticised the decision, saying the EU executive, the European Commission, would do better to study the real reasons behind the decline in bees rather than limit the use of new technologies in farming.

In May the Commission banned for two years beginning in December three insecticides made by chemicals giants Bayer and Syngenta.

Bayer of Germany and Switzerland's Syngenta insisted that their products were not to blame for a very sharp decline in the bee population which has stoked fears over future food security, made worse by the unpredictable impact of climate change.

The insecticides -- imidacloprid and clothianidin produced by Bayer and thiamethoxam by Syngenta -- are used to treat seeds and are applied to the soil or sprayed on bee-attractive plants and cereals.

Bee numbers have slumped in Europe and the United States in recent years due to a mysterious plague dubbed colony collapse disorder (CCD), which some reports have said has resulted in a loss of more than 40 percent of hives across the United States.