Seed-borne Pathogenic Fungi and Bacteria of Cowpea in Northern Nigeria

Fungal and bacterial flora of cowpea seeds in northern Nigeria were studied in agar plates and in plates containing moistened filter paper. Seeds were surface-sterilised with either sodium hypochlorite solution or mercuric chloride solution. About 90 fungal species, the vast majority of which were non-pathogens, were detected on seeds obtained from markets and from fields affected by various diseases. Cowpea pathogens detected on seeds from markets included Ascochyta sp., Colletotrichum lindemuthianum. C. truncatum, Rhizoctonia solani (Thanatephorus cucumeris), Fusarium oxysporum, F. solani, Macrophomina phaseolina, Septoria vignae and Corticium rolfsii. Except for Ascochyta sp., C. lindemuthianum and Fusarium oxysporum, all the above fungi were isolated from seeds from field plots which also yielded three other pathogens, namely Colletotrichum capsici, Cercospora canescens and Xanthomonas vignicola. Seed-plant transmission was established for all pathogens, except C. canescens, detected on seeds from the field plots.