First author: Environmental Health/Water and Nutrients, Agriculture and Agri-Food Canada, 1 Airport Road Box 1030, Swift Current (SK) S9H 2X3 Canada; second and fifth authors: Institut de recherche en biologie végétale, Université de Montréal and Jardin botanique de Montréal, 4101 Sherbrooke est, Montréal (QC) H1X 2B2 Canada; and third and fourth authors: Natural Resource Sciences, Macdonald Campus of McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue (QC) H9X 3V9 Canada
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Accepted for publication 21 March 2005.
The Fusarium spp. causing Fusarium crown and root rot (FCRR) are ubiquitous and abundant in soils, but in contrast, disease expression is localized and sporadic. Previous studies have related FCRR infection to phenolic acids released by asparagus, to the repression of Mn-reducers in soil, and to various soil physicochemical conditions. Fifty commercial asparagus plantations were surveyed using an exploratory approach in order to pinpoint the ecological conditions associated with FCRR development. Twenty-eight variables were used to describe the soil environments of the asparagus crops as well as the influence of crop management practices used locally. The data set was analyzed both as a whole and parsed by main cultivars (Jersey Giant and Guelph Millenium). Both field conditions and percentage of field area affected by FCRR varied widely between asparagus plantations. Planting depth was positively correlated with percentage of field area affected by FCRR and, hence, deep planting may favor FCRR infection. Plantation age was positively correlated with percentage of field area affected by FCRR, while soil available Mn was inversely correlated. Most importantly, soil Mn availability decreased with increasing plantation age, supporting the hypothesis of an asparagusmediated negative impact on Mn-reducing bacteria and of the involvement of reduced Mn availability in FCRR development. Improving the availability of Mn could provide a solution to the problem of FCRR in asparagus plantations.
crop management factor
ecology of disease expression
soil available manganese
The American Phytopathological Society, 2005