Current Season Needle Necrosis (CSNN) has resulted in significant losses for some Christmas tree growers as affected trees have become unmarketable.
The disease, thought to be caused by the fungus Sydowia polyspora, has resulted in greatly reduced crop yields, with losses of as much as £60,000 for a single grower.
CSNN affects Nordman Firs, the dominant species grown in the UK, and some other species, causing a red necrosis on the current season's needles. The causes of the problem and how it spreads are not known and there is no control available for the disease.
ADAS consultant Janet Allen said: "This is not associated with premature needle drop in trees that have been harvested because these trees will never reach the market.
"The potential for losses in the industry is that they may have trees they have grown for six or seven years and are then unable to sell them in the year they want to market them. This could mean that the crop of trees they have reduces significantly. We can't say how much it would be - it could be 10 per cent or it could be 50."
She added that it was not clear how many growers were hit. "It's fair to say it is widespread, but we really don't know how widespread. Looking at the way it has manifested abroad it is probably more common than people realise. One grower I have worked with has lost £60,000 worth of trees because they just can't market them."
Hans Alexanderssen, owner of grower HA Trim, said he had been hit and that he would be discussing the problem with other growers and the British Christmas Tree Growers Association.
Industry seeks answers with added research
"It's clearly a problem that we've experienced. We have a study group working on it and we will hopefully be able to find some answers for the next season. It's a problem in Europe and North America as well. We are using all the research available and doing our own to see whether we can ascertain the reason - or reasons, because there may be more than one. It affects some growers but not all."
Roger Hay, secretary, British Christmas Tree Growers Association.