The "See it. Snap it. Send it" campaign, being spread by posters and leaflets, calls on anyone who suspects they have spotted a diseased tree to photograph it and submit this along with its location, by email, text, WhatsApp or via Facebook.
While the mainland UK lost 90% of its elms to Dutch elm disease between 1968 and 1980, the Isle of Man remained free of the disease until 1992. Local vigilance and control measures have so far kept losses to just 1% of the island’s elm population, which accounts for a quarter of all trees on the island.
David Cretney MLC, the government minister with responsibility for forestry, said: "The Isle of Man has arguably the most important native elm population in the British Isles and possibly Europe.
"While we can be proud that it has kept the disease under control, it requires constant vigilance. We hope the public will report anything suspicious while using our beautiful countryside and ensure we can take swift action to avoid the disease spreading."
The "conundrum" of the trees' largely disease-free status is meanwhile investigated in a new survey by researchers from the Royal Botanic Garden Edinburgh.
"It is possible that the limited impact of Dutch Elm Disease on the Isle of Man elm population is due to a high frequency of disease resistance in the population," they suggest. "A first step in assessing the likelihood of this hypothesis is establishing with confidence which elm taxa are present."
But they conclude: "Further research to establish the composition of elms on the Isle of Man and why Dutch Elm Disease has had such a limited impact on the elm population there is needed."
The results are published in the New Journal of Botany.