A leading plant pathologist told Norfolk farmers that he feared pesticide bans could reduce the EU's wheat output by 21 million tonnes – enough to feed 90 million people for a year.

Bill Clark, the commercial technical director at NIAB (National Institute of Agricultural Botany) was the guest speaker at Stoke Ferry Agricultural Association's meeting at Ryston Park Golf Club near Downham Market.

He gave an update on the latest scientific understanding of wheat diseases including yellow rust and septoria, and the changing chemistry needed to control the infections in the face of rising resistance to pesticides.

A key fungicide group is triazoles – which are among the substances under review as part of a European Commission's public consultation on 'how to regulate chemicals in the environment in terms of their ability to affect the endocrine system, which produces, stores and releases hormones in the body'.

Many cereal fungicides contain triazoles and the commission is looking at whether pesticides can be classified as endocrine disruptors which could subsequently be banned in the EU.

The consultation closes on January 16, and Mr Clark said he was concerned that the voice of the farming industry could be outweighed by environmental lobbyists – as, he claimed, it was in the previous debate about neonicotinoids, which were banned amid concern over their affect on bee declines.

'I have written endless reports to say how important triazoles are, and what the problems would be if we were to lose them in the UK,' he said.

'It is a bit like the neonics. We lost those on a political whim, it was not on the science. The evidence was there, but there were simply more 'greens' arguing against them than there were farmers and practitioners arguing to keep them. I am worried that the same might happen with triazoles.

'My fear is that if one or two get banned, the greens might say ban the lot. And if they did ban the lot we would be in trouble. Without triazoles we would lose 21 million tonnes of wheat from the EU. That's roughly the amount we export, and it would feed 90 million people for a year.

'If we stop exporting, wheat prices would fall and it would have an impact on developing countries. There are all sorts of risks politically and socially.'

One of the groups arguing against the use of certain pesticides is Chem Trust, a UK health protection charity that works to prevent man-made chemicals from causing long term damage to humans or wildlife, by ensuring that chemicals which cause such harm are substituted with safer alternatives.

Gwynne Lyons, a Norwich-based policy director at the charity, is a former member of the Health and Safety Commission's advisory committee on toxic chemicals, and worked on the government's advisory committee on hazardous chemicals from 2001-2008.

She said endocrine disrupting chemicals had been linked to fertility problems and hormone-related cancers including breast, testicular and prostate in a report by the World Health Organisation (WHO).

'If you look at all the hormone-related cancers, they have all gone up in the last few decades,' she said.

'It cannot just be the genes, so the concern is that our exposure to any disruptive substances can be associated with cancer, low sperm count and other hormone-related diseases and disorders.

'The costs of those are enormous and if we have to look for alternative pesticides then I have every faith that the chemical companies can come up with them, if they are given a mandate to do so. This scare-mongering does nothing to help the debate.

'I don't think any one substance is likely to be causing these effects, but if you think we are exposed to many plastics, pesticide residues and some from substances in the home, this consultation is about the EU trying to reduce that overall exposure.'

To respond to the consultation, click here.