ABSTRACT
The interaction between Fusarium root rot and 4 allelochemicals in asparagus seedlings was
estimated in vitro to clarify the
relationship between biotic and abiotic factors in asparagus decline. In in vitro culture of Fusarium oxysporum f. sp. asparagi (Foa) with or
without addition of 4 allelochemicals (caffeic acid, ferulic acid, quercetin,
malic acid; 0.01%, 0.1%, w/v) using Czapec-Dox media, Foa propagation was
suppressed in all the treatments. The degree of suppression became higher in
0.1% than 0.01% among all the allelochemicals. As for the axenic culture of
asparagus (Asparagus officinalis L., “Welcome”)
seedlings with the 4 allelochemicals, dry weight of both shoots and roots became lower compared to control in 0.1%
and 0.01% of caffeic acid, 0.1% ferulic acid, 0.01% quercetin, only dry weight
of shoots decreased in 0.1% malic acid. Two weeks after Foa inoculation with
Foa-cultured PDA cubes in vitro,
incidence of Fusarium root rot reached
100% in most of the plots. The severity of root rot increased in 0.01% and 0.1%
caffeic acid, 0.1% ferulic acid, 0.1% malic acid compared to control. From
these results, the 4 allelochemicals used in this study are supposed to
suppress asparagus growth, and such growth reduction might enhance the disease severity
of Fusarium root rot as an indirect
effect. In addition, such effect might differ with the allelochemicals and
concentrations in asparagus.