The morphology of Verticillium albo-atrum, V. dahliae, and V. tricorpus

摘要

Abstract Important taxonomic differences between Verticillium albo-atrum, V. dahliae, and V. tricorpus occur in the morphology of the conidiophores and the conidia. These differences are additional to the morphological differences in the resting mycelium, and justify the recognition of different pathogenic species of Verticillium, causing wilt diseases in a wide range of hosts. Verticillium albo-atrum on natural host material typically has larger conidiophores with a dark swollen base; larger conidia. mainly 3.5–8 × 2–3μ. occasionally one septate; dark thickened resting mycelium and dark swollen hyphae; hyphal “knots” but no microsclerotia; a lower temperature range for growth on media and pathogenicity; a more restricted host range; a greater degree of pathogenicity than V. dahliae at 20°c towards many hosts (including tomato, cucumber, and strawberry). Verticillium dahliae on natural host material typically has fewer. smaller. completely hyaline conidiophores. smaller conidia. mainly 3–6 × 1.5–2μ; abund...