ISHS Acta Horticulturae 271: VII International Asparagus Symposium
SURVEY OF FUSARIUM POPULATIONS IN MICHIGAN'S ASPARAGUS FIELDS. |
| Authors: | A.C. Hartung, C.T. Stephens, W.H. Elmer |
| Abstract:
Soil densities of Fusarium spp. were monitored in 28 fields in two counties in Michigan. Of these, 23 were or had been planted to asparagus while five had no history of asparagus culture. Soil samples were removed within rows and between rows in randomly picked areas within each field. Populations were estimated by conventional soil dilutions onto selective media. Although variation was high, Fusarium colonies were higher within rows than between them, and greater in one-year-old plantings in 1982 and 1983 than in older fields. Ninety-two of 244 (38%) subcultured isolates of F. oxysporum that were recovered from fields of all ages incited lesions on asparagus (U.C.157) seedlings. F. moniliforme was recovered more frequently from plant debri than sieved soil and all isolates of F. moniliforme were virulent. Soils that had no history of or proximity to asparagus culture still harbored low densities of F. oxysporum and F. moniliforme. Resident populations of these pathogens may be common to most agricultural soils in Michigan. | |
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