Disease Note

First Report of Powdery Mildew, Erysiphe spp., on Arrowleaf Clover in Georgia. J. D. Miller, USDA-ARS, Coastal Plain Station, Tifton, GA 31793. H. D. Wells, USDA-ARS, Coastal Plain Station, Tifton, GA 31793. Plant Disease 68:351, 1984. Accepted for publication 24 January 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-351e.

Powdery mildew mycelia and conidia were observed on plants of arrowleaf clover (Trifolium vesiculosum Savi) in May 1982 and May 1983 in Georgia. Infection ranged from light to heavy on individual plants. Perithecia were not found, but conidia were indistinguishable from those of Erysiphe polygoni DC. on red clover. The fungus found on arrowleaf clover infected arrowleaf, crimson, subterranean, red, and white clovers in growth chambers, whereas powdery mildew from red clover infected only red and white clovers. Powdery mildew occurs annually on red clover at Tifton; adjacent seedlings of arrowleaf were disease-free before 1982.