Resistance of African Violet to Powdery Mildew and Efficacy of Fungicides for Control of the Disease. D. L. Strider, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Plant Dis. 64:188-190. Accepted for publication 28 September 1979. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-188.

The incidence of powdery mildew (Oidium sp.) differed significantly among 48 cultivars of the Melodie and Ballet series of African violets (Saintpaulia ionantha). The incidence also differed significantly between leaves and flowers of the same cultivar. The most resistant, overall, were Allison, Brilliant Eva, Dolly, Mitzi, Pearl, and Rachel. Cultivars with the most susceptible leaves were Erica, Heidi, Julianne, Karla, Lisa, Margaret Ann, Meta, Paula, Pink Ulli, Sheri, and Suzanne. Flowers were most susceptible on Diane, Frances, Georgeanne, Helen, Jeanie, Mary, Paula, Renee, and Sheri. Benomyl at 1, 2, or 4 oz a.i./100 gal eradicated mildew from Erica African violets without causing phytotoxicity. Dinocap and sulfur were efficacious but phytotoxic to blossoms.