ISHS Acta Horticulturae 479: IX International Asparagus Symposium
CHARACTERIZATION OF FUSARIUM POPULATIONS IN ASPARAGUS FIELDS IN THE PACIFIC NORTHWEST |
| Authors: | M.C. Doan, L.M. Carris |
| Abstract:
Asparagus decline is a complex problem involving biotic and abiotic factors. The main pathogens associated with asparagus decline in the US are Fusarium oxysporum and F. proliferatum. Plant and soil samples were collected from twenty-two declining and twenty-six non-declining asparagus fields in Washington and Oregon between 1994 and 1995. Fusarium was isolated from root, crown, and stem tissues using Komada's medium. Fifty-five and thirty-nine percent of tissue samples yielded F. oxysporum and F. proliferatum, respectively. Seventy isolates of F. oxysporum were tested for pathogenicity to asparagus seedlings. Eighty-five percent of F. oxysporum isolates tested were pathogenic to asparagus. Fusarium oxysporum was also isolated from 99% of the soil samples. Isolates putatively identified as F. proliferatum, F. moniliforme and F. subglutinans were paired with tester isolates from mating populations A, B, and D in the Section Liseola. Sixty-nine percent of the isolates were compatible with F. proliferatum mating population D, and 78% of those were of one mating type. Twenty-five percent of isolates tested were compatible with mating populations A and B, F. moniliforme and F. subglutinans, respectively. There were no consistent differences noted in F. oxysporum and F. proliferatum populations in asparagus fields sampled in Washington. However, asparagus fields sampled in Hermiston, OR, had significantly lower levels of Fusarium. | |
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