Journal of Taiwan Agricultural Research

Author:Chiao-Wen Huang, Hong-Ren Yang, Ching-Yi Lin, Sui-Li Hsu, Su-Yu Lai, and Hui-Fang Ni*

Abstract:

    Foot rot disease is a major limiting factor for sweet potato production in recent years. In this study, foot rot of sweet potato was investigated in different growing regions of Taiwan. Results showed that the disease was harmful to commercial root-used varieties of sweet potato, ‘TN57’ and ‘TN66’, as well as vegetable-used variety, ‘TN71’, suggesting that the major cultivars of sweet potato in Taiwan were not resistant to the disease. The optimal temperature of mycelial growth and spore germination of Phomopsis destruens were 20℃ and 25–30℃, respectively. The maximum incidence of foot rot disease occurred in range of 15–30℃. The incidence of foot rot was 100% when the diseased seedlings were grown in uninoculated soil for 12 wk, suggesting that the disease seedling was a major inoculum source. Therefore, good quality of seedlings would be an important factor to control the foot rot of sweet potato in the field. However, when the field grown with diseased tuber and stem were treated with flooding for 1 wk and 2 wk, respectively, the disease incidence of foot rot was reduced to zero. As a result, the field with the foot root disease should be rotated with paddy rice annually or flooded for more than 2 wk after the previous harvest to eradicate the pathogen avoiding the infection in the next season.

Key words:Sweet potato (Ipomoea batatas), Foot rot disease, Phomopsis destruens, Disease control

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