Fungi colonizing roots of zucchini (Cucurbita pepo L. var. giromontina) plants and pathogenicity of Fusarium spp. to zucchini seedlings

Zucchini is a very valuable vegetable, easy to grow both in the field and under covers but it is often attacked by soil-borne fungi. The investigations were carried out in a farm near Lublin where three zucchini cultivars: Astra, Atena and Soraya, were grown in a tunnel and in the field in 2008-2009. Plants with stem and root rot were collected for laboratory tests. Mycological analysis showed that the predominant fungi were <i>F. culmorum</i>, <i>F. equiseti</i> and <i>F. oxysporum</i>. More <i>Fusarium</i> colonies were isolated from the roots of zucchini grown in the tunnel. In the pathogenicity test, all tested isolates of <i>F. culmorum</i>, <i>F. equiseti</i> and <i>F. oxysporum</i> proved to be pathogenic to zucchini seedlings, causing stunting, stem and root rot. The highest disease index was noticed in the combination with <i>F. culmorum</i> isolate fck61.