Stem and Crown Rot of Chervil, Caused by Sclerotinia sclerotiorum, in California.

Chervil (Anthriscus cerefolium) is a culinary herb grown commercially in California. In 1999, chervil plantings in shade houses in coastal California exhibited symptoms of a previously undescribed disease. Tan to gray lesions, surrounded by pinkish tissue, developed on crowns and lower sections of stems. Affected stems wilted, and plants eventually collapsed and rotted. More than 50% of the plants in the early spring planting were diseased. White mycelium and large, irregular, black sclerotia (3 to 6 mm diameter) were observed on infected stems and crowns. Isolations from symptomatic stems, mycelium, and sclerotia produced colonies of Sclerotinia sclerotiorum. Following previously described methods (2), pathogenicity was confirmed by culturing isolates on potato dextrose agar and allowing the fungus to colonize sterilized toothpicks placed on the surface of the agar. The pointed toothpick tips were inserted ≈3 mm deep in stems of potted chervil. Sterile toothpicks were inserted in control chervil plants. All plants were incubated in a mist chamber for 48 h and then kept in a greenhouse. Two other hosts of S. sclerotiorum, cauliflower (Brassica oleracea var. botrytis cv. White Rock) and celery (Apium graveolens cv. Conquistador)were inoculated in the same way. After 7 to 10 days, symptoms and mycelium similar to those originally observed developed on inoculated chervil plants, and S. sclerotiorum was reisolated. Plants left for 14 or more days supported sclerotia. Chervil inoculated with sterile, uncolonized toothpicks did not develop symptoms. Results were similar for cauliflower and celery plants. Pathogenicity tests were repeated, and the results were similar. A separate set of chervil was inoculated by placing sclerotia at the base of plants; these plants also developed disease but at a much lower incidence (<50%). This is the first report of Anthriscus cerefolium as a host of S. sclerotiorum. The related plant cow parsley (A. sylvestris) has been reported as a host of S. sclerotiorum in England (1). References: (1) M. J. Hims. Plant Pathol. 28:197, 1979. (2) S. T. Koike. Plant Dis. 81:1334, 1997.