6.1
FUSARIUM NELSONII AND F. MUSARUM: TWO NEW SPECIES RELATED TO F. CAMPTOCERAS, SECTION ARTHROSPORIELLA

JP RHEEDER1, WFO MARASAS1, A LOGRIECO2, PS VAN WYK3 and J JUBA4

1PROMEC, Medical Research Council, PO Box 19070, 7505 Tygerberg, South Africa; 2Istituto Tossine e Micotossine da Parassiti Vegetali, CNR, Bari, Italy; 3Grain Crops Institute, Agricultural Research Council, Potchefstroom, South Africa; 4Fusarium Research Center, Department of Plant Pathology, Pennsylvania State University, University Park, Pennsylvania, USA

Background and objectives
Two new populations which resemble Fusarium camptoceras Wollenweber and Reinking, a member of the Section Arthrosporiella Wollenweber, have recently been described [1] as distinct species, viz. F. nelsonii Marasas and Logrieco and F. musarum Logrieco and Marasas. This presentation illustrates the amended description of F. camptoceras, as well as the cultural and morphological characteristics of F. nelsonii and F. musarum.

Results and conclusions
Pedicellate macroconidia, infrequent and rare in sporodochia, are illustrated for F. camptoceras. The first new Fusarium species, F. nelsonii, was isolated from plant debris in soil in South Africa and some other sources, and differs from F. camptoceras primarily in the presence of red colony pigmentation, shorter macroconidia and aerial mesoconidia with fewer septa, and characteristic terminal pairs of chlamydospores. The second new Fusarium species, F. musarum, was isolated from banana fruit in Central America and differs from F. camptoceras primarily in the presence of red colony pigmentation and longer, inaequilaterally curved aerial mesoconidia with more septa, and the absence of sporodochia with pedicellate macroconidia. F. musarum differs from F. nelsonii in growing more rapidly on potato dextrose agar at 25 and 30C, the presence of inaequilaterally curved aerial mesoconidia with more septa, the absence of sporodochia with pedicellate macroconidia, and the presence of chlamydospores which are produced slowly and sparsely, and never in terminal pairs, as is characteristic of F. nelsonii. Both these new species have been placed within the Section Arthrosporiella.

Reference
1. Marasas WFO, Rheeder JP, Logrieco A et al., 1998. Mycologia (in press).