Sweet basil and other lamiaceae grown in the UK could be under threat from a new disease, never seen before in the country.
According to the Royal Horticultural Society (RHS), experts at its Garden Wisley site have identified the peronospora belbahrii pathogen in agastache plants in two sections of the site.
The infected specimens have been removed, but the occurrence has given cause for concern after epidemics in other parts of the world.
It was first reported in Africa in 1933, before appearing in the US and continental Europe 60 years later.
However, this is the first instance of it being seen in the UK and greenhouse enthusiasts should be able to spot it from its downy mildew symptoms.
Infected plants will have "chlorotic leaf spots, eventually turning brown and twisting of the leaves", the RHS revealed.
Meanwhile, the body revealed the maze at the foot of Joseph Paxtons Crystal Palace – which was built in the 19th century – is to be restored to mark the centenary of the Girl Guides movement.