Canavirgella banfieldii Needlecast of Pinus strobus in Michigan

In the winter of 1995 to 1996, browning and dieback of the 1995 needle complement of Pinus strobus L., resembling needlecast caused by Canavirgella banfieldii Merrill et al. (1), was observed in Antrim County, MI. (Needle dieback = distal portions of the needles die, but short basal segments remain living and diseased needles remain attached until normal shedding of the entire complement.) Affected needles at that time had not developed ascomata, but bore spent pycnidia resembling those of C. banfieldii. About 25% of the symptomatic needles collected on 7 June 1996 bore hysterothecia of C. banfieldii in various stages of development. On wetting about 8% of these opened and released mature ascospores. Voucher specimens are in BPI and PACMA. Heretofore, C. banfieldii has been known from western North Carolina to central New York, northern Vermont, and central and eastern Maine. This is the first report of this pathogen in the Lake States, a significant extension of its known distribution, and substantiates in part our belief that this long-overlooked fungus probably occurs throughout the natural range of P. strobus. Reference: (1) W. Merrill et al. Can. J. Bot. 74:1476, 1996.