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Etiology

A Variety of Collecephalus hemerocalli Pathogenic on Hemerocallis. J. N. Lunsford, Graduate Assistant, Department of Plant Pathology and Weed Science, Mississippi Agricultural and Forestry Experiment Station Mississippi State 39762; James A. Spencer, Associate Professor, Department of Plant Pathology and Weed Science, Mississippi Agricultural and Forestry Experiment Station Mississippi State 39762. Phytopathology 66:245-248. Accepted for publication 14 October 1975. DOI: 10.1094/Phyto-66-245.

A fungal isolate (DAR), obtained from daylily plants grown in Maryland was compared with Collecephalus hemerocalli. Notable differences existed between the two fungi in the amount of growth and degree of pigmentation on three culture media at six temperature levels. Differences in growth of the two fungi were obtained at both 12 and 32 C. Conidia of DAR were significantly greater in length and width than those of C. hemerocalli. Isolate DAR was consistently less pathogenic than C. hemerocalli and separation of the two was determined by responses of 10 daylily cultivars. Since these fungi differ significantly in morphology and pathogenicity, DAR is considered a distinct variety of C. hemerocalli. It is described as C. hemerocalli var. macrosporum n. var.