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The Use of Various Substrates for Large-Scale Production of Fusarium oxysporum f. sp. cannabis Inoculum. D. C. Hildebrand, Department of Plant Pathology, University of California, Berkeley, CA 94720; A. H. McCain, Department of Plant Pathology, University of California, Berkeley, CA 94720. Phytopathology 68:1099-1101. Accepted for publication 26 January 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1099.

Chlamydospore formation was enhanced in Fusarium oxysporum f. sp. cannabis in an aqueous solution individually amended with beef extract, soytone, proteose peptone #3, glycine, β-alanine, succinate, lactate, or NaNO₃. Chlamydospore formation was less with glucose, (NH₄)₂SO₄, tyrosine, and tryptone. The ideal defined medium for chlamydospore formation was a solution of glycine-succinate-NaNO₃. Diffusates from alfalfa straw, cottonseed meal, and soybean oil meal induced chlamydospore formation, but few spores were formed with diffusates from sugar beet pulp, barley straw, or safflower meal. Large-scale inoculum production by the fungus was achieved by culturing the fungus on a mixture of barley straw plus either the glycine-succinate-NaNO₃ solution, alfalfa straw, cottonseed meal, or soybean meal. Chlamydospores produced on the glycine-succinate-NaNO₃-barley straw substrate retained their disease potential over a 6-mo period at room temperature.