Polish immigrants and tourists may have been responsible for the introduction to Scotland of a tree-killing moth that has already wiped out swathes of pine forest in eastern Europe.

Scientists believe the pine tree lappet moth, which has been discovered in woodlands near Inverness, may have been inadvertently transported by vehicle or luggage from Poland, where it is endemic.

Scientists have warned that the moths are a threat to Scotland’s £800m-a-year forestry industry and businesses in economically fragile, rural areas that rely on pine. They also fear that the insects could devastate the natural habitats of species such as red squirrels, capercaillie and Scottish crossbill.

Officials have discovered around 100 adult moths, as well as larvae, in the Inverness area. The moths, with wingspans of up to three inches, produce caterpillars that feed on pine needles. The defoliation leaves the trees susceptible to attacks by bark beetles and wood boring insects.

Among the tree species targeted by the moths are the Scots pine, Sitka spruce, Douglas fir, larch and lodgepole pine, all of which are grown commercially in Scotland.

Only a handful of the moths had been discovered in Britain, on the south coast of England, over the past 200 years. They are thought to have been blown over from Europe. A breeding population has never been found before.

An outbreak in Germany during the 1990s caused damage to more than 83,000 hectares of woodland. More than 54,000 acres of pine woodland in Poland had to be treated for pine tree lappet in 2007.

“One possibility which we always have to take account of in any new pest infestation is that of accidental or deliberate release,” said Roddie Burgess, head of the commission’s plant health service. “There is a population of Polish workers in Inverness. Possibly one of them came back in their car or van and there was contamination of some sort.”

The Forestry Commission Scotland, Butterfly Conservation Scotland and Scottish Natural Heritage have launched an investigation into how the insects arrived in Scotland and how far they have spread.

Forty-two trees have been felled at six sites, including the Forestry Commission’s Boblainy forest, to determine the extent of the infestation.

The commission said that it had investigated other potential causes for the moth’s presence in Scotland such as imported plants and wood but had all but ruled them out.

It is also carrying out DNA testing in an attempt to determine if the moths are a previously undiscovered species that has lived in Scotland for some time, though initial tests show this is unlikely.

If the moth is found to be damaging a lot of trees, large-scale felling or pesticide would be used to eradicate it.

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