The first confirmed case in the Isle of Man of a usually fatal tree disease which can devastate the ash population has been found, the government said.
The presence of Chalara dieback, caused by the Chalara fraxinea fungus, has been confirmed by laboratory in the UK.
Chalara dieback, which causes leaf loss and bark lesions, was discovered on private land in an undisclosed location on the Isle of Man.
It was first detected in the UK in Surrey five years ago.
Control on imports into the Isle of Man has ensured the island has been free of the disease until now, the government said.
"While Chalara ash dieback is not harmful to other tree species or to the health of humans or animals, it can be fatal to ash trees, particularly younger specimens," said a spokesman.
The Manx environment department said: "Landowners can reduce the risk of disease spread by burning or composting ash leaf litter and keeping associated machinery, tools and vehicles clean.
"Visitors to the countryside can also help by not removing any plant material and by keeping footwear and clothing clean of soil and plant material."
Experts are urging people to report suspected cases of dieback in order to prevent its spread.