The effect of soil pH on sclerotial germination and pathogenicity of two isolates of Sclerotium rolfsii on peanut was examined. Sclerotial germination for both isolates was greater (P ≤ 0.05) in acidic soil than at alkaline pHs. Similarly, percentage of peanut stems infected by S. rolfsii in greenhouse tests was greater at soil pH 5.6 than at alkaline soil pHs (P ≤ 0.05), but disease did develop at soil pH 8.7 and 9.8. In contrast to a previous in vitro study, these data confirm that sclerotia of S. rolfsii will germinate and initiate disease at soil pH > 7.0.

Arachis hypogaea, groundnut, peanut, stem rot, sclerotia
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Author notes

1 This study was partial fulfillment of the requirements for the first author's Ph.D. degree. Supported by the Texas Peanut Producers Board and USDA IPM grant no. 92-34103-6937.

American Peanut Research and Education Society
1997
American Peanut Research and Education Society