The discovery of the disease, caused by the pathogen Phytophthora ramorum, is the first of its kind in Scotland and was described as a "real blow" to Scotland's forestry by commission director Dr Bob McIntosh.
The disease was first found in Britain in 2002 and has since been found on Japanese larch in south-west England, Wales, Northern Ireland and the Republic of Ireland.
The west coast of Scotland is particularly susceptible because P. ramorum thrives in wetter climates. Symptoms include wilting shoot tips and needles turning black and falling off prematurely.
McIntosh said: "The disease sporulates very heavily on Japanese larch. The best way to prevent it spreading is to fell the trees to kill the living tissue on which the organism depends."
Any suspected cases of ramorum disease in Scotland should be reported to the Tree Health Diagnostic & Advisory Service at the Forestry Commission's forest research arm in Midlothian.