Suppression of the plant diseases, Pythium (damping-off), Rhizoctonia (root rot) and Verticillium (wilt) by vermicomposts

摘要

Vermicomposts are stabilized, non-thermophilic materials produced from organic wastes by interactions between earthworms and microorganisms Suppression of Pythium by vermicomposts was tested by substituting 0, 10, 20 and 40 percent of vermicomposts(by volume) into 100, 90, 80 and 60 percent of a soil-less plant growth medium Metro Mix 360 (MM360), inoculated with Pythium at a rate of 1:4000 by volume. Disease severity was rated after 10 days, from 1 (symptomless) to 4 (heavy). The disease severityrating was 3.4 in 0 percent vermicompost substitution, compared with 1.1 in 10 percent substitution, 1.3 in 20 percent substitution, and 1.1 in 40 percent substitution. A similar range of substitutions of sterilized or non-sterilized MM360 and vermicompost was tested in three experiments with radish seeds inoculated with 1:2000 or 1:667 by volume of Rhizoclonia. Suppression of Rhizoctonia by vermicomposts was correlated progressively with increasing rates of substitution of vermicompost in three experiments. In field experiments planted with strawberries, the incidence of Verticillium wilt was suppressed significantly by the application of 5 t/ha and lOt/ha of commercial paper and food waste vermicomposts.