Disease Note.

Sclerotium rolfsii Crown and Root Rot of Kiwi (Actinidia chinensis). R. D. Raabe, Department of Plant Pathology, University of California, Berkeley 94720. . Plant Dis. 72:1077. Accepted for publication 23 August 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-1077B.

Kiwi (Actinidia chinensis Planch.( has become an important crop in California. Recently, Sclerotium rolfsii Sacc. was isolated from wilted plants with crown and root rot grown in the Sacremento Valley. Kiwi is usually planted in old orchard or grape vineyard land, so this disease has not been a serious problem. It is a potential problem, however, if kiwis expand into cropland). To prove pathogenicity, sclerotia taken from dried potato-dextrose agar plants of the kiwi isolate were added to U.C mix approximately 800 gm of mix. This inoculum was divided evenly and put on the outside of root balls of 20 plants growing in 12.7-cm clay pots. Ten plants each were grown at 32.2+ 2 c and 26.6 + 2 C. Two plants were grown at each temperature in pots to which no inoculum has been added. After 5 wk, seven plants grown at 32.2+2 C and 26.6 +2 C. Two plants were grown at each temperature in pots to which no inoculum had been added. After 5 wk, seven plants had symptoms similar to those in the field, and S. rolfsii was isolated from all infected plants. This is beleived to be the first report of S. rolfsii on A. chinensis