a disease of pines caused by the rust fungus Melampsora pinitorqua and characterized by the distortion of shoots. In the spring the causative agent forms sporecases on pine shoots; in the summer and autumn sporecases in the form of yellowish brown (summer) and dark brown (autumn) scabs appear on the leaves of aspen and white poplar. Pines become infected between the ages of one and ten years. The mycelium winters in the bark. The tree becomes severely distorted owing to warping of the shoots.
Control measures include planting pines far from aspens and white poplars, gathering and burning aspen leaves in areas near to pine plantings, and early-spring spraying of pine seedlings with fungicides.