VIEW ARTICLE

Ecology and Epidemiology

Colonization of Soybean Seeds and Plant Tissue by Fusarium Species in Soil. R. L. Schlub, Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge 70803; J. L. Lockwood(2), and H. Komada(3). (2)Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824; (3)Central Agricultural Research Station, Ministry of Agriculture and Forestry, Konoso, Saitama 365, Japan. Phytopathology 71:693-696. Accepted for publication 6 December 1980. Copyright The American Phytopathological Society. DOI: 10.1094/Phyto-71-693.

Emergence of soybean (Glycine max) seedlings was greatly reduced in a sandy loam soil naturally infested with 5–10 × 10³ propagules of Fusarium per gram and kept at –15 bars matric potential for 4–6 days before it was watered to a level sufficient for seed germination. Treatment of the soil with both benomyl and fenaminosulf restored seedling emergence to 80%, whereas fenaminosulf alone did not. Emergence of seedlings was significantly reduced in fumigated soil infested with Fusarium solani, F. tricinctum, F. moniliforme ‘Subglutinans,’ or F. oxysporum and when seeds were incubated in the soil at –15 bars for 6 days before watering. Incubation of sterilized and unsterilized dead plant tissue pieces in field soil at –0.01 to –0.02 and –1.8 bars resulted in a twofold to 32-fold increase in the number of Fusarium propagules in the soil. The increase in propagules was confined to within 3 mm of the tissue surface, after 16 days. Incorporating soybean plant residues into the upper 3 cm of soil in a field in October increased the number of propagules of Fusarium in the bulk soil over a 5- to 6-mo period, but after 7–8 mo the population did not differ from that in unamended soil.