Tell-tale signs were spotted in private woodlands north of Newton Stewart, west Scotland, in the third outbreak on Japanese larch in the country this year. The first two were found on trees on the Craignish peninsula and island of Mull.
Resinous lesions characterise the disease, which turns wilting tree needles grey or blackish and can kill a tree within a few months. The only way to contain the disease is to chop down affected and surrounding trees.
Forestry Commission Scotland tree-health policy adviser Hugh Clayden said: "We are working with land managers to confirm the extent of the infections and the measures required to deal with them. We ask woodland owners to remain vigilant and report any suspected signs of tree disease."