Norwich scientists leading the fight against a “devastating” plant disease have welcomed tighter government controls on importing high-risk plants including olive trees.

The stricter regulations have been introduced to curb the spread of Xylella fastidiosa, which has destroyed olive groves in Italy and is a growing economic and environmental threat across southern Europe.

The disease, which can infect more than 500 species of plant, prevents water travelling from roots to leaves, causing leaf scorch, wilt, dieback and plant death, and could hit garden favourites such as lavender and oleander, rosemary and flowering cherry if it was to arrive in the UK.

Imports of certain plants which have a high rate of Xylella infection are now prohibited, including Coffea species which include coffee plants, and Polygala mytifolia, also known as the myrtle-leaf milkwort or sweet pea bush.

And rules have been tightened on importing a range of other high-risk hosts including olive, almond, lavender, Nerium oleander and rosemary, said Defra.

The John Innes Centre, based on the Norwich Research Park, is leading a UK-wide consortium named BRIGIT, which is working to generate the evidence and understanding needed to reduce the risk of Xylella being introduced to this country.

Prof Saskia Hogenhout, leader of the consortium at the John Innes Centre, said: “We welcome these new regulations which will be a key step in keeping the UK free from Xylella.

“Through the BRIGIT programme we are investigating how Xylella may spread in the UK environment, by assessing how symptoms may develop in plants, the prevalence and movement of insect vectors and how the disease may move around the country via transport of plants. We also organise public engagement events to distribute information about Xylella and risks associated with importing ornamental plants into the UK.

“All of these components are vital in developing an effective regulatory framework to manage the threat posed by the disease.”

READ MORE: Lessons learned from farm experiment which solved pest problem – but ruined cropThe regulations announced this week aim to protect against threats to natural habitats and forestry and horticulture industries.

They also include stronger import controls on wood from countries within 100km of a confirmed outbreak of emerald ash borer to prevent the spread of the invasive beetle which could harm UK ash trees already facing devastation from ash dieback. And imports of plane trees intended for planting from Albania, Armenia, Switzerland, Turkey, the US and EU, other than seeds, must now have been grown throughout their life in a pest-free area or EU protected zone to prevent the spread of plane tree wilt.

UK chief plant health officer Nicola Spence said: “Xylella is a major threat to our landscape and industry, and in this Year of International Plant Health it is more imperative than ever that we do all we can to ensure the UK remains a Xylella-free zone.

“Emerald ash borer and plane wilt also represent significant threats, which is why we are bolstering our protection against them, in response to recent changes in the risk situation.”