A new strain of the disease Xylella fastidiosa ssp. multiplex, is worrying the grower, who has spoken to concerned Dutch nurserymen. Many Dutch growers are looking at stopping importing from France and Italy, and McCurdy says that is something the UK industry must look at too.
However, he said landscapers, designers and private individuals are a more likely source of the disease coming into the UK, although large commercial nurseries such as his would suffer if the disease is found within an exclusion zone near their nursery.
The disease has 150 hosts and causes scorch on trees including pedunculate oak, wych elm, plane and northern red oak. In May, the EU strengthened conditions for import and movement within the EU of specified plants known to be susceptible to Xylella fastidiosa, but McCurdy says they include "the apparent EU threat that any nursery that is found with this disease can be effectively closed down for five years" because demarcation zones may be imposed until the organism has not been present for five years.
McCurdy said in Holland there is "real alarm about the new EU legislation that came into force in May regarding Xylella fastidiosa and the apparent EU threat that any nursery that is found with this disease can be effectively closed down for five years. The Dutch nurserymen told us we needed to get our heads wrapped around this legislation before it was too late and that they were cancelling their orders with Italian nurseries as they couldn’t take the risk."
In a letter to Defra he said: "I think you do need to give us guidance as to what species we should not and from where we should not import, and what will really happen to us if the disease arrives on our nursery. Is the threat to the UK really this great, and if so do you think that the penalty for being foolish should be so high? It must be well thought through, fair and something where you would weigh up the evidence and if proven to be showing little care and thought that caused an outbreak, do; not simply threaten. Simply put, what is your interpretation of the EU document and how you will implement it?"
He said the nurseries in France and Italy are offering "desperate prices" to the strong UK market, and direct import by unscrupulous landscapers or individuals looking for cheap trees is a risk that could be combated by fines of up to £100,000. Other trees that carry the disease include Acers, Aesculus, Cercis, Cornus, Eucalyptus, Ficus, Ginkgo, Gleditsia, Juglans, Liquidamber, Liriodendron, Magnolia, Morus, Olea, Platanus, Quercus and Salix.
An APHA representative said: "If the PHSI found evidence or suspected that the pathogen had spread then a precautionary approach would be taken based on relevant such as laboratory testing results, length of time the plant has been present, contact with hosts, treatments applied, presence of vectors etc. Essentially, the greater the degree of risk that the pathogen has had an opportunity to spread, the greater the likelihood that stringent measures would need to be taken."
Xylella: ‘A threat that we don’t want in’ says John Adlam
HTA horticulture head Raoul Curtis Machin said: "The HTA is watching this like a hawk but we don’t know exactly how devastating it could be."
The HTA does not want to alarm growers unduly but is concerned about the new strain, having previously believed the disease may not prosper in the colder UK climate. Nursery consultant John Adlam said Xylella is "a threat that we don’t want in".
He said it was right to inspect plants coming into the UK and ultimately, the disease could give "a boost to UK production" if the industry boasts it does not have the disease when other countries have it.
APHA said the disease is becoming more worrying now it is in France and because the multiplex strain affects so many genera.
APHA said the symptoms include leaf scorch that looks like chemical burn.
Plants for Europe owner Graham Spencer said Xylella could be a big theme in 2016: "I think the Xylella problem is going to really hit hard over the next year or two and some supply chain options, particularly offshore unrooted cutting production, will cease to be available for that reason. Growers seem to be waking up to it – my friends at APHA say that they are getting more enquiries from growers who are worried about it.
"I know some growers (Ball) are putting unrooted cutting production in Portugal so that they have an EU-based production solution in case they can’t import certain genera from outside the EU – but we are seeing new restriction on internal EU movement of Xylella hosts, initially from southern Italy but I think the south of France will be next."