Biotic effects of mycoflora of leaves, glumes and seeds on Septoria nodorum foliowing Triticum aestivum treatment with fungicides

Using a biotic series method, interactions between Sepfona nodorum and associated fungal communities isolated from leaves, glumes, and seeds of spring Triticum acstivum. cv. Kolibri treated with Bayleton 25 WP. Dithane M-45. and Funaben K were determined. Control planls were sprayed with water. Most fungi accompanying S. nodorum in the field inhibited the growth of this pathogen on a potato glucose agar medium. Fungi which restricted the growth of S. nodorum the most were Chaetomium globosum, Fusarium spp., Helminthosporium sativum, Mucor hiemalis, Rbizophus nigrieans, Stemphylium botryosum, Trichothecium roseum, and two non-sporulating forms. Septoria nodorum replaced Cladosporium spp. and a yeast-like pink fungus. The biotic resistance to S. nodorum increased with me age of plant. The fungal populations recovered from plants sampled in 1982 and 1983 inhibited the growth of S. nodorum whereas most of those isolated in the relatively wet and cold year 1984 favoured the development of this pathogen, The lowest biotic resistance of the fungal communities investigated to S. nodorum was generally found following spraying of plant s with Bayleton 25 WP, and ihe highest in Funabed K - and water-treated plants