Other problems for the amenity sector include the rise in grounds maintenance costs and the blocking of drains and watercourses.

Depending on how chemicals are categorised during the plenary vote, active substance 2, 4-D - used to treat broad-leaved weeds in amenity and grassland areas - could be removed from use. The substance used to treat invasive species Japanese knotweed and other pernicious weeds, picloram, is also under threat.

BALI technical director Neil Huck said: "A new development needing 350sq m of Japanese knotweed clearance would cost £50,000. This would rise to £500,000 without the ability to use herbicides."

Industry figures are also concerned that removal of herbicides will lead to buildings deteriorating through buddleia growth and public and workforce safety issues on railways and highways.

"Vegetation growth across the ground means the danger of slips and falls," said Network Rail senior lineside engineer Dr Neil Strong.

Fungicides are the most highly threatened group in the plant protection armoury. Sports Turf Research Institute head of turfgrass protection Dr Ruth Mann warned: "There's always the chance that all the fungicides could go."

Their removal would lead to increased diseases such as Fusarium in sports turf, and the treatment of Impatiens downy mildew, which affected so many parks displays this year, would not be possible.

"It will affect the wide range of varieties we currently use and we would expect not to see so much colour," said Nottingham City Council nursery manager Glenn Springthorpe. "We use Impatiens quite widely and the problem of downy mildew means there will need to be an increased spraying programme, but we may not be able to do that."