Journal of Taiwan Agricultural Research

Author:Ching-Yi Lin* and Hui-Ju Lin

Abstract:

    Ralstonia solanacearum is the causal agent of the plant disease known as bacterial wilt, which is a serious threat to potato industry worldwide. Control of bacterial wilt is very difficult, largely being dependent on good crop management practices such as the uses of healthy tubers, pathogen-free soil and crop rotation. A greenhouse study was conducted to determine effects of neutralized phosphoric acid solution (NPA) on control of bacterial wilt of potato. The disease severity of inoculated potato plants was decreased to 40% when 0.08% NPA applied as soil drench, whereas the disease severity of inoculated potato plants was 92% by foliar spray application of 0.08% NPA. The results indicated that soil drench application of NPA provided better disease control than the foliar spray. Concentration effects of NPA on control of bacterial wilt of potato were evaluated through soil drench. A significant reduction in disease severity was observed at 0.10% and 2.00% NPA 28 days after inoculation and the disease severity ranging from 0.00% to 46.67%. At low concentration of 0.05% NPA, disease severity slightly decreased to 83.33%. However, treatment with a high concentration of 2.00% NPA was found to stunt potato growth and inhibit tuberization in greenhouse. Thus, application of NPA concentration more than 1.00% is not feasible. The mechanism of action of NPA is still unclear, as it only affects multiplication of R. solanacearum in vitro.

Key words:Phosphoric acid, Potato, Bacterial wilt

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