Ash dieback will be more devastating than Dutch elm disease, according to a leading trade nursery that is advising landscape contractors to use a mix of trees instead of one alternative to ash to "spread the risk".
Crowders Nurseries, which had to destroy 50,000 ornamental and native-seed ash trees at one of its two sites in Lincolnshire, is one of 12 nurseries found by plant inspectors to show traces of the killer disease, said chairman Robert Crowder.
"That was our Horncastle site, but our Woodhall Spa site, where we grow more than 250,000 ash, has been inspected regularly and no evidence of the disease was found," he added.
"We are saying don't plant any ash trees even if they are healthy - they could be infected by airborne transfer of the fungus next year and you would have to destroy them all. There's a potential liability issue in future if you plant now.
"This is the tip of the iceberg and I think ash dieback will be more devastating than Dutch elm disease to the open countryside. Landscapers should be okay but nurseries will be the big losers while arboriculture contractors with chainsaws will do very well."
He also warned landscape and tree-planting contractors to rely on a mixture of trees instead of one alternative to ash to "spread the risk". The entire sector is playing a waiting game until the next planting season to see the full scale of the horror, he said.
Crowder, who will seek Government compensation, criticised the authorities for focusing resources on nurseries when the disease has been apparent in the open countryside for three years. Ash makes up to a third of our hardwood tree population.
Palmstead Nurseries sales and marketing manager Nick Coslett said: "We moved to prevent any imports several weeks ago but it now looks like our stock is banned from movement. If we are found to be in a risk area, our 1,000 trees are probably doomed."
Staff are advising landscape contractors on other trees including natives such as Walnut, which is similar to ash but uncommon, Alianthus with similar foliage, rowan or Tillia cordata.
Interviewed before the ban on imports was announced, Barcham Trees sales director Keith Sacre said he had stopped buying ash and demand had fallen. His stock of 1,000 trees has been cleared and he advised contractors to check only official guidance to avoid lots of "garble and misinformation".
He added: "Contractors in future will have to question whether they buy imported stock directly for transplanting. We don't have to stop imports but they should spend at least a year in a UK nursery with full pest and disease control programmes."
Nick Coslett, sales and marketing manager, Palmstead Nurseries
"Landscapers need to refresh themselves with the 30-20-10 rule - plant:30 per cent from one family, 20 per cent from one genus and 10 per cent from one species. That way you will plant a landscape diverse and robust enough to survive a genusor species-specific disease."