Articles
Potato scab management with Brassica biofumigation and effect of volatiles on Streptomyces growth
Article number
1269_4
Pages
25 – 32
Language
English
Abstract
Common scab of potato is an economically important soilborne disease caused by various Streptomyces species.
The disease is very difficult to control, but biofumigation has recently shown some potential.
Biofumigation consists of the incorporation of Brassica spp. crop residues containing glucosinolates that upon cell disruption are hydrolysed by the enzyme myrosinase to yield a diversity of biologically-active hydrolysis products, of which volatile isothiocyanates are the most toxic to soil microbes.
In this study common scab was significantly reduced through soil incorporation of fresh and air-dried residues of Brassica oleracea var. capitata (cabbage) when applied prior to two consecutive potato plantings.
The in vitro effect of volatile emissions from various Brassica species on pathogenic and non-pathogenic Streptomyces isolates was also evaluated using a bioassay method.
In the chamber bioassay freshly macerated Brassica tissue, (B. oleracea var. capitata and B. juncea/S. alba mix) suppressed sporulation but not hyphal growth of the 79 evaluated Streptomyces isolates.
The chamber bioassay also showed that the Brassica tissue volatiles were bacteriostatic, since isolates re-grew when removed from the chamber and transferred to fresh media.
The results suggest that soil biofumigation could significantly influence composition of the Streptomyces community in agricultural soils and lead to significant suppression of common scab on potato.
The disease is very difficult to control, but biofumigation has recently shown some potential.
Biofumigation consists of the incorporation of Brassica spp. crop residues containing glucosinolates that upon cell disruption are hydrolysed by the enzyme myrosinase to yield a diversity of biologically-active hydrolysis products, of which volatile isothiocyanates are the most toxic to soil microbes.
In this study common scab was significantly reduced through soil incorporation of fresh and air-dried residues of Brassica oleracea var. capitata (cabbage) when applied prior to two consecutive potato plantings.
The in vitro effect of volatile emissions from various Brassica species on pathogenic and non-pathogenic Streptomyces isolates was also evaluated using a bioassay method.
In the chamber bioassay freshly macerated Brassica tissue, (B. oleracea var. capitata and B. juncea/S. alba mix) suppressed sporulation but not hyphal growth of the 79 evaluated Streptomyces isolates.
The chamber bioassay also showed that the Brassica tissue volatiles were bacteriostatic, since isolates re-grew when removed from the chamber and transferred to fresh media.
The results suggest that soil biofumigation could significantly influence composition of the Streptomyces community in agricultural soils and lead to significant suppression of common scab on potato.
Authors
R. Gouws-Meyer, A. Mcleod, M. Mazzola
Keywords
potato, biofumigation, management, bacterial disease, bioassay
Groups involved
- Division Temperate Tree Fruits
- Division Vine and Berry Fruits
- Division Tropical and Subtropical Fruit and Nuts
- Division Ornamental Plants
- Division Vegetables, Roots and Tubers
- Commission Banana
- Division Horticulture for Development
- Division Precision Horticulture and Engineering
- Division Plant Genetic Resources, Breeding and Biotechnology
- Division Plant-Environment Interactions in Field Systems
- Division Postharvest and Quality Assurance
- Division Greenhouse and Indoor Production Horticulture
- Division Landscape and Urban Horticulture
- Division Horticulture for Human Health
- Commission Cultivar Registration
- Division Temperate Tree Nuts
- Commission Agroecology and Organic Farming Systems
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