Witzell J, Karlsson A
Anisogramma virgultorum on saplings of Betula pendula and Betula pubescens in a district of northern Sweden
Forest Pathology: 2002 32:207-212
During the autumn of 1999, the occurrence of the ascomycete Anisogramma virgultorum on saplings of Betula pubescens and Betula pendula was studied in two stands of B. pubescens, two stands of B. pendula and two mixed (B. pubescens and Pinus sylvestris ) stands (age approximately 10 years, mean height 2-4 m, d.b.h. 10-20 mm) in a district in the vicinity of Umea, northern Sweden. Stem and branch cankers associated with A. virgultorum were found on 54.8% of the investigated saplings, without significant difference between B. pendula and B. pubescens. Cankers were observed on 16.0% of stems and on branches of 54.2% of the saplings. Stem cankers appeared on the current year's shoot, as well as at the base of the trees. The mean diameter of the damaged saplings was significantly greater than the mean diameter of undamaged saplings. All samples of cankers with stromata examined in the laboratory showed perithecia with asci.
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