Disease Note.

Crown and Root Rot of Chives in California Caused by Sclerotium rolfsii . S. T. Koike, University of California Cooperative Extension, Salinas 93901. T. G. Gonzalez, and E. D. Oakes, University of California Cooperative Extension, Salinas 93901. Plant Dis. 78:208. Accepted for publication 28 October 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0208D.

Commercial fields of chives (Allium schoenoprasum L.) grown on the coast of California showed patches of declining plants in February 1993. Older leaves first became chlorotic, then later faded to pale tan, and eventually collapsed. Newer leaves exhibited the same range of symptoms. The crowns of plants became rotted and collapsed. Characteristic white mycelial growth, development of tan, spherical sclerotia on the soil adjacent to the affected plants, and isolations from chives crown tissues confirmed the pathogen to be Sclerotium rolfsii Sacc. Inoculum of the fungus was produced in flasks of sterilized oat seeds, distilled water, and 1% Difco Bacto agar (1). After 3 mo, sclerotia were harvested and dried at room temperature for 48 hr and added to steam-sterilized sand at the rate of 20 sclerotia/100 cm3 of soil. Sixty-day-old chives seedlings, germinated and grown in plug trays, were transplanted into pots containing the inoculated soil. Chives were also planted into steam-sterilized soil without sclerotia. All plants were incubated at 22-24 C. After 3 wk, older leaves of inoculated plants began to turn chlorotic; by 5 wk, inoculated plants had collapsed, and S. rolfsii was reisolated from the infected tissue. Control plants showed no disease symptoms. This is the first report of S. rolfsii causing crown and root rot of chives