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Biological Control of Ergot by Fusarium. R. L. Mower, Research Assistant, Department of Plant Pathology, University of California, Berkeley 94720, Present address of senior author: Department of Chemistry, University of California, Berkeley 94720; W. C. Snyder(2), and J. G. Hancock(3). (2)(3)Professor Emeritus, and Associate Professor, respectively, Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 65:5-10. Accepted for publication 14 June 1974. DOI: 10.1094/Phyto-65-5.

Fungal hyperparasites of Claviceps purpurea were examined as potential biological control agents for ergot of wheat. The most virulent hyperparasites of ergot from a worldwide collection were certain cultivars of Fusarium roseum. The pathogenicity of isolates was tested under both glasshouse and field conditions. Promising strains were reisolated from glasshouse-infected ergot sclerotia and screened with regard to their toxicity and host-parasite relations. As a result of both field and clinical tests, a clone of F. roseum ‘Sambucinum’ was determined to be a highly effective biological control agent of ergot. Breakdown of ergotamine by this clone to psychotropically inert substances was observed: neither rabbits nor rats displayed deleterious effects after administration of 5 mg equivalent- or 10 mg equivalent per kg body wt of hyperparasite-digested ergotamine, respectively, during tests for subacute toxicity.