||Assessment of chitosan oligosaccharide efficacy on control of leaf blight and angular leaf spot diseases of strawberry
||草莓是臺灣重要的經濟作物，近年來因品種更迭，造成兩大新興病害─葉枯病與細菌性角斑病的出現，而目前臺灣種植最多的香水品種對葉枯病極為感病，造成農民嚴重損失，為現今草莓產業急需解決的病害問題。本研究由尋求可用於臺灣草莓產業的天然安全資材切入，藉由測試幾丁寡醣對草莓葉枯病和細菌性角班病致病菌之抑菌能力，並觀察其對病害嚴重度的影響，評估幾丁寡醣應用於防治此二種草莓新興病害之效果。結果顯示，幾丁寡醣可以抑制葉枯病菌孢子發芽，但無法完全抑制細菌性角斑病菌於培養基中的生長。每週以 5,000 mg/L 幾丁寡醣施於草莓植株時，防治葉枯病效果佳，可以顯著降低發病嚴重度，但用於防治細菌性角斑病則無效；以幾丁寡醣防治葉枯病需每週噴施，兩週施用一次則無效果。本研究提供了幾丁寡醣應用於草莓葉枯病防治潛力之成效，以及合適的施用頻率及濃度，希望未來可將幾丁寡醣導入田間草莓有害生物整合管理 (Integrated pest management, IPM) 的策略中，以達到減少化學藥劑施用量與頻率的目標。
||Strawberry is an important cash crop in Taiwan. Recently, the alternation of cultivars has resulted in the emergence of two diseases, leaf blight and bacterial angular leaf spot of strawberry. Xiang-Shui, the most cultivated variety in Taiwan, is highly susceptible to leaf blight, which results in enormous economic loss for farmers and aggravates the disease problem in the strawberry industry. Searching for natural products for disease control applicable to the strawberry industry in Taiwan, we assessed the efficacy of chitosan oligosaccharide (COS) in controlling these two diseases. The antimicrobial activity of COS on Neopestalotiopsis rosae and Xanthomonas fragariae and its control efficacy were thus evaluated. The results showed that COS could inhibit spore germination of N. rosae ML2411 but not the growth of X. fragariae B001. Weekly application of 5,000 mg/L COS onto strawberry plants resulted in a better control effect on reducing the severity of leaf blight disease. However, it is ineffective in controlling bacterial angular leaf spot disease. Weekly, but not biweekly, application of COS could control Neopestalotiopsis leaf blight of strawberry. This study provides data on the potential of COS application for the control of strawberry leaf blight and the appropriate application frequency and concentration. We hope that COS can be introduced into the integrated pest management (IPM) program for strawberries in the future to reduce the amount and frequency of chemical applications.
- Leaf blight of strawberry
- Bacterial angular leaf spot of strawberry
- Chitosan oligosaccharides (COS)
- Integrated pest management (IPM)