Source of Inoculum, Yield, and Quality of Tomato as Affected by Leveillula taurica. W. B. Jones, Former Graduate Research Associate, Department of Biology, Utah State University, Logan 84322-5305. S. V. Thomson, Associate Professor, Department of Biology, Utah State University, Logan 84322-5305. Plant Dis. 71:266-268. Accepted for publication 7 August 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0266.

Tomato transplants from southern Nevada were the primary source of inoculum of Leveillula taurica and showed disease symptoms of powdery mildew about 3 wk before Utah-grown tomato transplants. Plants from Nevada and Utah were equally infected 7 wk after planting, and no differences in severity or yield were detected at the end of the season attributable to rapid spread of the fungus. Tomato yields were reduced about 40% in check plots compared with plots treated with triadimefon, propiconazol, or sulfur. The amount of sunburned fruit in check plots was three to four times greater than in plots where the disease was controlled. Yields from benomyl and dinocap treatments were no greater than those from check plots.

Keyword(s): Oidiopsis taurica, Oidium taurica.