Growth of Fungi in Sorghum Grain Stored at High Moisture Contents. Rosemary Burroughs, Research Assistant, Department of Plant Pathology, Kansas State University; D. B. Sauer, Research Plant Pathologist, Market Quality Research Division, ARS, USDA. Phytopathology 61:767-772. Accepted for publication 1 February 1971. DOI: 10.1094/Phyto-61-767.
Sorghum grain moistened to 18, 20, 22, and 24% moisture content (MC) was stored 7 weeks. At 25 C, the percentage of seeds yielding Fusarium increased at 20-24% MC; Penicillium grew at 18-24% MC; Trichothecium grew at 22-24% MC; but Alternaria decreased with increasing moisture content and time.
In sorghum harvested at 25% and 29% MC and stored 10 weeks at 15 and 25 C, Alternaria increased for a few days, then decreased. Fusarium grew more rapidly at 29% MC than at 25% MC. When the sorghum was stored at 15 C, other principal fungi were Verticillium, Scopulariopsis, and Trichothecium at 25% MC, and Verticillium, Mucor, and yeasts at 29% MC. At 25 C, the other principle fungi were Penicillium at 25% MC and Aspergillus flavus at 29% MC.
Viable, fungus-free sorghum grain was obtained from seed treated with captan, stored for about a year, and the fungicide washed off with 70% ethanol and water. Isolates of Mucor, Alternaria, Aspergillus repens, and Fusarium moniliforme were able to invade sorghum at 23% MC and 15 C, with F. moniliforme as the best competitor. Rate of invasion was similar in naturally infected and fungus-free viable grain.