Rapid screening of potential plant-growth rhizobacteria from soils to control chili wilt disease and to promote growth and yield of chili

Chili wilt disease is a devasting fungal and bacterial disease that affects several plants in the Solanaceae family, causing severe damage to the plant and often leading to crop losses.
The disease is caused by the soil-borne fungus (Fusarium spp.) and bacterial (Ralstonia solanacearum), which enters to the plant’s vascular system and blocks the water and nutrient flow to the upper part of the chili plant.
However, chili wilt disease is difficult to control due to the fact that there are no effective chemical controls.
Biological control is a desirable method with rhizobacteria as the biological agent that can control chili pathogens and enhance the growth and yield of chili.
In this study, soil samples were collected from different locations of healthy crop rhizosphere at Nan Province, northern part of Thailand.
The rapid screening method of rhizobacteria isolated from soils to control chili wilt was based on spray pathogen inoculation on agar plate technique.
This technique can easily detect antagonistic microorganisms without disturbing the bacterial colonies that are already grown on the agar surface.
The isolation of antagonistic bacteria was spreading diluted soil solution first on selected agar plates.
Then, the plates were sprayed with the spore suspension of (Fusarium spp.) or bacterial suspension of Ralstonia solanacearum. Antagonistic bacteria with inhibition zones against pathogen were selected and isolated in pure culture.
One isolate, BNC5, from isolated antagonistic bacteria showed strong antagonistic effects on both pathogens of wilt disease; and was used in filed experiments for evaluating effects of disease control.
The selected strain of rhizobacteria showed high potential for disease suppression and increased growth and yield of chili in the field’s conditions.

IV Asian Horticultural Congress – AHC2023

P. Tiyayon, R. Manopack, T. Weeplian, W.J. Liang

chili, Fusarium spp., plant growth rhizobacteria, Ralstonia solanacearum, screening, antagonistic, wilt disease

https://doi.org/10.17660/ActaHortic.2024.1404.64