Spreading fungus, not cheer

Not everyone wants a real Christmas tree—after all, they only last one season and make a mess with all that dropped foliage—but many do like to have the choice. Unfortunately, levels of Dothistroma pini, a toxic fungus that causes red banded lesions on pine needles and premature defoliation, could affect such decisions.

A number of countries in the Northern hemisphere, including the United Kingdom, France, and Canada are reporting an upsurge in the severity and distribution of D. pini infection. Milder and wetter weather conditions are partly to blame, as the spread of this pathogen is favored under moist, warm, light, and sheltered conditions.

Anna Brown, who heads the Dothistroma Project at Forest Research, UK, told The Scientist: "This disease has become particularly noticeable over the past 2 years and has apparently been increasing in frequency for 5 to 6 years. In the 2002–2003 period, we found over a quarter ...