Invasion of red clover (Trifolium pratense) roots by soilborne fungi

Abstract

Abstract Red clover plants were grown in the glasshouse in pots containing soil (at 20°C) from breeders' evaluation plots with a history of poor persistence of red clover. Fungal invasion of plants grown from seed treated with a mixture of metalaxyl and benomyl (each at 1.5 g(kg seed), of plants grown from untreated seed in sOIl drenched WIth a mixture of metalaxyl (0.15 g/m2) and benomyl (1.0 g/m2), and of untreated plants, was investigated using plate culture isolation techniques. Seed- and soil-drench fungicide treatments increased seedling emergence and prevented post-emergence damping-off. Pythium ultimum Trow and an unidentified sphaerosporangiate Pythium sp. were Isolated from roots of untreated seedlings which dampedoff. Fungi commonly isolated from surface-sterilised tap roots of 3- and 6-week-old treated and untreated plants were (in order of decreasing frequency): Fusarium oxysporum Schlecht., sterIle dark forms, F. solani (Mart.) Sacc., Chalara elegans Nag Raj & Kendrick (= Thielaviopsis basic...