Invasion of white clover roots by fungi and other soil microorganisms

Abstract

Fungi and actinomycetes isolated from white clover roots growing in some New Zealand pasture soils were tested in the glasshouse for their ability to invade the roots of very young clover seedlings. Of the 109 isolates tested, 52 comprising genera of imperfect fungi, ascomycetes, and basidiomycetes formed necrotic root. lesions packed with fungal hyphae. A further 23 isolates penetrated roots but caused no necrosis. Root invasion by the oomycetes Pythium irregulare Buis., Phytophthora megasperma Drechsl., and two other Pythium spp. was particularly extensive. These results confirm that many of the fungi which comprise the diverse microtlora naturally present within white clover roots can invade growing root tissues; some may be potential root pathogens.

Keywords:

• soil fungi
• root rots
• white clover
• Trifolium repens
• Leguminosae
• Phythium irregulare
• Phytophthora megasperma
• plant pathogens
• actinomycetes
• oomycetes
• Peronosporaceae
• Vaucheriales
• Phycomycetes