Fungi colonising the above-ground parts of fodder galega (Galega orientalis Lam.) cultivated in pure sowing and mixed with smooth brome-grass (Bromus inermis Leyss.)

Abstract

Field experiments were carried out in 1999-2001 in the experimental field in Knopin near Dobre Miasto to determine the intensity of fodder galega diseases cultivated in pure sowing and mixed with smooth brome-grass (the Hillstrand and Auld' s modified scale, 1982). The fungi colonising the phyllosphere of fodder galega were analysed in a laboratory (Chruoeciak , 1974). The following symptoms were observed in fodder galega: ascochyta blight (<i>Ascochyta</i> sp.), gray mould (<i>Botrytis cinerea</i>) and plant wilting (<i>Fusarium oxysporum</i>.). The climatic conditions had an effect on the development of diseases. The greatest intensity of gray mould (Ii = 24.3%) and plant wilting (17.9% of plants with the disease symptoms) were observed in 2001. Ascochyta blight occurred with the lowest intensity and the highest infection index in 1999 in the cultivation of fodder galega mixed with smooth brome-grass was only 12.1%. The type of cultivation also modified fodder galega disease intensity. Gray mould and plant wilting developed better in pure sowing than in mixed sowing with smooth brome-grass. Throughout the entire experiment period the average infection index was 22.8% and 15.9% of plants with the wilt symptoms. Ascochyta blight found better conditions for development in plants cultivated in a mix with smooth brome-grass (average infection index - 10.0%). The fodder galega phyllosphere provided 4149 fungal isolates represented by 17 species and yeast-like fungi. Yeast-like fungi dominated (75.6% of the total isolates). The following species were less numerous: <i>Botrytis cinerea</i>, <i>Humicola brevis</i>, <i>Acremonium strictum</i> and <i>Cladosporium cladosporioides</i>. From the leaves of fodder galega cultivated in pure sowing, 3.8% more fungi were obtained than from the leaves of plants cultivated with a mix of smooth brome-grass, including more frequently isolated pathogenic fungi representing the genera of <i>Fusarium</i> and the species of <i>Botrytis cinerea</i>.