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Disease Note. First Report of Spinach Anthracnose in Ontario. R. F. Cerkauskas, Agriculture Canada, Vineland Station, Ontario L0R 2E0. R. Nauta, and M. R. McDonald. O.M.A.F., Muck Research Station, Kettleby, Ontario L0G 1J0. Plant Dis. 75:101. Accepted for publication 17 August 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0101C. In 1989, 50 ha of commercial spinach (Spinacia oleracea L.) near Stouffville, Ontario, was affected by anthracnose caused by Colletotrichum dematium (Pers.) Grove f. spinaciae (Ellis & Haist.) Arx. Infected plants were stunted, and foliage was blighted and necrotic. Small, translucent lesions developed on young leaves. Dark acervuli with setae were present in mature lesions. Hyaline, one-celled, falcate conidia from acervuli averaged 24.4 X 4.0 µm and conformed to those reported elsewhere (I1). Isolations from affected tissue onto potato-dextrose agar consistently yielded C. dematium. Pathogenicity was proved by spray-inoculation of 44-day-old spinach cultivars America, Tyee, Melody, and Vienna; beet (Beta vulgaris L.) cultivars Little Egypt, Big Red, and Vermillion; bean (Phaseolus vulgaris L.) cultivar Frenchie; and Spanish onion (Allium fistulosum L.) cultivar Kelsae with a suspension of I X 105 spores per milliliter (one plant per pot, four replicates). After 14 days, only spinach cultivars were severely diseased with characteristic symptoms; beet cultivars had numerous red pinpoint lesions, and Frenchie bean and Kelsae onion had no symptoms. C. d. f. spinaciae reisolated from infected spinach plants produced cultures identical to the original ones. This is the first report of the disease on spinach in Ontario. |