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Disease Control and Pest Management

Factors Affecting Penicillium oxalicum as a Seed Protectant Against Seedling Blight of Pea. Carol E. Windels, Associate Scientist, Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108; Thor Kommedahl, Professor, Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108. Phytopathology 68:1656-1661. Accepted for publication 24 May 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1656.

Effectiveness of Penicillium oxalicum as a pea seed treatment was improved significantly by: (i) using spores harvested from a Czapek-Dox or a potato-dextrose agar medium and to a lesser extent from an oat grain medium; (ii) applying at least 3 × 10⁶ and preferably 6 × 10⁶ spores per seed; and (iii) storing organism-coated seeds for 2 mo at 5 C instead of 24 C prior to planting. Spore ages from 20 to 125 days were equally effective when applied as inoculum for seed treatment. Penicillium oxalicum was not deleterious to pea germination or otherwise pathogenic to peas. Penicillium oxalicum was more effective in controlling preemergence than postemergence damping-off.