News from the gardening world
Nursery industry and RHS prepares for new tree threat
Plans are being drawn up to help prevent a devastating disease from entering the country.
Xylella fastidiosa, a bacterial wilt disease, is already established in the Puglia region of Italy, devastating olive tree plantations, hitting yields of berries and oil. Now the Horticultural Trade Association (HTA) in the UK has given a grave warning that an outbreak in this country would wreak havoc.
“Xylella fastidiosa is one of the most harmful bacterial plant diseases in the world,” it said in a statement. “It can cause severe losses in a wide range of hosts and in the event of an outbreak in the UK there would be a massive impact on the plant trade across all business sectors.
“An outbreak, where several different plants are infected, will trigger immediate stock destruction within 100 metres and a movement ban of host plants within a 10 kilometre radius for up to five years. This will dramatically and immediately affect most plant-selling operations, as well as impacting on businesses dealing in plants within the 10km zone. Gardens could also be affected.”
The HTA has now launched an e-learning video for the industry, which it hopes will go some way to preventing the disease entering the UK.
The microscopic pathogen, spread by sucking insects such as spittlebugs and froghoppers, causes blockages in the waterconducting tissues of infected trees, leading foliage to scorch and wilt, with whole plants dying back. Since its discovery in 2013, it has been found in other parts of the Mediterranean, including France and Spain. Further types have been discovered, including a more cold-tolerant ‘multiplex’ strain that attacks up to 300 hosts, including English oak, plane and Wych elm. Two strains of the disease are established in the USA, infecting grapes, citrus, coffee and almonds as well as oleander.
The government’s Animal and Plant Health Agency (APHA), along with the Forestry Commission, is concerned that susceptible trees and shrubs imported from the continent will bring the disease into the UK. Some plant suppliers, nurseries and garden centres have already started trading in only Britishraised plants. To date there has only been one interception of xylella in the UK, on an ornamental coffee plant, which was subsequently destroyed.
The RHS has already taken action, telling exhibitors that only British-grown hebe, rosemary, lavender, oleander, olive, polygala, coffee, Spanish broom and prunus will be allowed at its shows next year, including Chelsea.