First Report of Sclerotinia sclerotiorum on Salvia in the United States. V. L. Jons, Agassiz Crop Consulting, Moorhead, MN 56560. J. R. Venette, H. A. Lamey and M. P. McMullen, Department of Plant Pathology, North Dakota State University, Fargo 58105-5012. Plant Dis. 80:1302. Accepted for publication 5 September 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-1302C.
On 1 August 1995, plants of (he weed lanceleaf sage (Salvia reflexa Hornem.) growing in a dry bean (Phaseolus vulgaris L.) field in Cass County, ND, were observed with wilting foliage and extensive stem lesions. The lesions were bleached, soft, and extended from near the soil line to halfway up the 70-cm stems. In some areas, external tissues were covered with matted, aerial hyphae. The steins shredded easily and exposed large (3 mm diameter x 3 to 5 mm), darkened sclerotia within the pith cavity. Isolations from the sclerotia and from lesion margins on Scle-rattma-selective medium (2) produced colonies characteristic of the pathogen. Hyphal tip transfers of the colonies onto acidified potato dextrose agar produced abundant aerial mycelium and large sclerotia indicative of Sclerotinia sclerotiorum (Lib.) de Bary. Pathogenicity was confirmed on inoculated cucumber with formation of watery soft rot, white aerial mycelium, and black sclerotia up to 1 cm in diameter. Mycelial inoculations onto 10 lanceleaf sage plants, transplanted from field collections and maintained in a humid chamber (90+% relative humidity, 25°C), produced wilted shoots and soft-rotted stems after 72 h. The pathogen was recovered from diseased stems on the selective medium. While lanceleaf sage is known from various locations across the state, it is gaining importance because it is not readily controlled by inexpensive herbicides. The weed is associated with a number of crops and grows readily in headlands and row crops with open canopies. Infection of lanceleaf sage and other weed hosts may perpetuate the pathogen on fallowed land or in crops such as cereals that are planted to reduce populations of Soilborne sclerotia. S. sclerotiorum has an extremely broad host range, and the pathogen causes yield-limiting epidemics on crops in North Dakota. Dry bean, sunflower, canola, and lentil are especially susceptible. Several other weeds are susceptible (1). While a Salvia sp. was reported as a host in Canada, this is the first report of Sclerotinia sclerotiorum on a member of the genus Salvia in the United States.References: (1) G. J. Boland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (2) J. R. Steadman et al. Can. J. Plant Pathol. 16:68, 1994.