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Disease Note: First Report of Brown Spot of Lupines Caused by Pleiochaeta setosa in Canada. T. C. Paulitz, Macdonald Campus of McGill University, Ste. Anne de Bellevue, Quebec, H9X 1C0, and Nova Scotia Agricultural College, Truro, Nova Scotia B2N 5E3. G. Atlin, Macdonald Campus of McGill University, Ste. Anne de Bellevue, Quebec, H9X 1C0, and Nova Scotia Agricultural College, Truro, Nova Scotia B2N 5E3. Plant Dis. 76:1185. Accepted for publication 1 August 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-1185C. A severe stem and pod rot of white lupines (Lupinus albus L.)
was observed in germ plasm evaluation trials in Truro, Nova Scotia,
and Sussex, New Brunswick, in August 1991 during pod filling.
Discolored brown seeds from infected pods, surface-dis infested with
0.5% NaOCI for 3 min and plated on potato-dextrose agar (PDA)
+ 100 µg/ml of chloramphenicol, gave rise to colonies with dematiaceous
phragmospores with apical filamentous appendages, identified as
Pleiochaeta setosa (Kirchn.) S.l. Hughes. A suspension of 104 conidia
per milliliter was sprayed onto 2-mo-old white lupine plants in the
greenhouse, and the plants were enclosed in plastic bags for 48 hr
at 25 C with 12 hr light per day. Typical symptoms appeared after4 days, including brown stem and leaf lesions and infection of flowers
and pods. The pathogen was reisolated on PDA + chloramphenicol.
P. setosa was also isolated from seed harvested from field plots in
the fall of 1991, with an incidence of almost 50% in some accessions.
The fungus is a major seed borne pathogen on lupines worldwide.
In North America, it has been primarily reported from the southern
United States but was recently isolated in Minnesota (1). The pathogen
could pose a serious limitation to the introduction and cultivation
of lupines in eastern Canada, especially in areas with high summer
rainfall. |