Image caption A decline in bee numbers has been linked by the EU to use of some pesticides

The European Commission has proposed that member states restrict the use of certain classes of pesticide that are believed to be harmful to bees.

Sprays that use neonicotinoid chemicals should only be used on crops that are not attractive to the insects they said.

The sale of seeds treated with these chemicals should also be prohibited.

Bayer, one of the companies who make the pesticides, says they are convinced they can be used without harm to bees.

Earlier this month, the European Food Safety Authority (Efsa) issued guidance on the use of neonicotinoids, in which they recognised "high acute risks" to bees who encountered residue from these sprays in pollen and nectar in crops like oilseed rape and sunflowers.

They also said there were risks to bees from dust in crops like maize that had been sprayed with these pesticides.

The evidence linking neonicotinoid chemicals to declining bee populations is growing. Andrew Pendleton, Friends of the Earth

However they stopped short of recommending a complete ban.

Now the European Commissioner for health and consumer policy Tonio Borg has adopted the same line saying it was time for "swift and decisive action."

Significant step

He has tabled a discussion paper that asks EU member states to restrict the use of neonicotinoids to crops not attractive to bees and to prohibit the sale and use of seeds treated with products that contain the active substances.

Three pesticides would be affected -clothianidin, imidacloprid and thiametoxam. Farmers would be banned from using them with sunflowers, oilseed rape, cotton and maize.

Commission spokesman Frederic Vincent told BBC News the measure was based on the latest scientific advice.

"We have requested a proper scientific assessment of neonicotinoids from Efsa. They came up with some concerns, some kind of worrying assessment. So now we are saying to members we have some scientific evidence that there are some concerns from those pesticides and the effects they might have on bees," he said.

The Commission wants restrictions in place by July and the measures will be reviewed after two years. There are already bans in place in France, Germany and Slovenia.

Campaigners were delighted with the EU stance - Friends of the Earth's Andrew Pendleton said it was a timely move.

"This hugely significant EU proposal promises a first, important step on the road to turning around the decline on our bees. The UK Government must throw its weight behind it," he said.

"The evidence linking neonicotinoid chemicals to declining bee populations is growing. We can't afford to ignore the threat they pose to these crucial pollinators.

Museum agriculture

But Bayer CropSciences which manufactures some of the chemicals that face restrictions says it remains convinced that neonicotinoids can be used safely and effectively in sustainable agriculture.

Speaking to the House of Commons environmental audit committee yesterday, the company's Dr Julian Little said that Europe was in danger of "enshrining some sort of museum agriculture".

"I personally absolutely support very strict regulation, but not to the point where we believe you are taking out major advances in chemistry and major advances in agriculture with no discernible improvement in bee health. And other countries will continue to use these products," he said.

In the UK the Department for Environment, Food and Rural Affairs (Defra) rejected a ban late last year saying the scientific evidence wasn't clear. They have commissioned new studies that will look at the impacts of neonicotinoids on bumble bees in field conditions and to understand what levels of pesticide residues and disease in honey bees are normal. These are due to be completed shortly.

But if the EU agrees to limit the use of these pesticides, it will apply to the UK as well, according to spokesman Frederic Vincent.

"If what we have tabled today is approved by members states in the short run, it will mean there will be a new regulation and the measures would apply from the first of July to everybody," he said.

In recent days a number of UK retailers have removed from sale neonicotinoid chemicals linked to bee decline.