Disease Note

First Report of Phoma spp. on White Lupine in North America. T. C. Paulitz, Department of Plant Science, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 1C0. E. Cote, Department of Plant Science, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 1C0. Plant Dis. 75:862. Accepted for publication 4 April 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0862E.

White lupine (Lupinus albus L.) is grown in Quebec as a possible forage legume adapted to cool spring soil temperatures. Lupines collected at Ile D'Orleans and Emil Lods Seed Farm of Macdonald College in southern Quebec showed reddish brown lesions on the lower stems. Lesions originated from petiole scars and contained concentric rings of brown-black pycnidia. Similar lesions were observed on mature pods. The fungus was identified as Phoma sp. on the basis of conidial and pycnidial morphology on potato-dextrose and V8 juice agars. Leaves and stems of white lupine plants were inoculated (by airbrush or wounding) in the greenhouse with a spore suspension of Phoma spp. Plants were incubated at 20 C for 48 hr at 100% relative humidity. After I wk, inoculated plants were defoliated and characteristic lesions formed on stems. Phoma sp. was reisolated from stem lesions and was also isolated from surface-disinfested, discolored brown seed. Similar inoculations of alfalfa (Medicago sativa L. 'Vernal'), pea (Pisum sativum L. 'Laxton Progress'), soybean (Glycine max (L.) Merr. 'Maple Arrow'), and red clover (Trifolium pratense L.) produced no symptoms. On the basis of these studies, the fungus is probably Phoma lupini Ellis & Everh., reported on L. mutabilis Sweet in Peru and on native lupines in the western United States. To our knowledge, however, no species of Phoma has been reported on cultivated lupines in North America.