氣候變遷對水稻病害相之可能影響及其因應策略

Influence of Climate Change on the Incidence of Rice Diseases and Our Adaptive Strategies

氣候變遷與植物病害管理的關係相當複雜，目前多數研究僅能針對控制1項或2項氣候因子，探討其對寄主、病原菌或2者之交互作用的影響，對植物病害的衝擊仍難以評估。聯合國跨政府氣候變遷小組指出，未來全球暖化與大氣中二氧化碳濃度的升高，可能導致海平面上升、降雨量、降雪量的變化及極端氣候的頻繁。台灣自1901年至2000年間，陸地平均溫度已上升1.3℃，暖化速度是全球總平均兩倍，且夜溫上升的幅度大於日間，日夜溫差有下降趨勢。除溫度變動外，CO2濃度、病蟲害相、氣候因子等的改變，都對水稻產量有所影響。本文就台灣目前較重要的水稻病害，包括稻熱病、徒長病、紋枯病、胡麻葉枯病及白葉枯病，可能受氣候變遷（包括氣象因子、CO2濃度與養分變化）的影響，進行初步討論，並提出因應策略，希望藉由選育抗病品種、改善栽培管理技術、落實病害共同監測等方法綜合運用，依據病害發生種類、配合氣候條件，掌握正確防治時機及防治技術，有效降低受害程度。未來建置中長期的氣象資料、病害預報的即時及準確性的提升，是需積極進行的工作；研究部分，探討個別氣候因子對病原菌與寄主間的影響機制及動態關係，包括對病原菌的世代長短、有性生殖、生存適應、族群變化、擴散及遺傳與生態等的影響，都是非常重要的課題。

"A complex relationship exists between climate change and plant pest management. Available studies have been based on the effects of limited environmental factors on host plants, pests, and/or their interactions. The lack of knowledge makes it difficult to predict the impacts of climate change on plant diseases. The United Nations Intergovernmental Panel on Climate Change warned in its 2007 report that global warming and increasing atmospheric concentration of carbon dioxide can potentially cause sea level rise, widespread changes in precipitation, as well as more frequent extreme weather events. In Taiwan, average land temperature has risen by 1.3℃ from 1901 to 2000, which is twice the Earth's average warming rate. The rapid increase in nighttime temperature has resulted in a decrease of difference between daytime and nighttime temperatures. Changes in not only temperatures but also carbon dioxide concentrations, pest epidemics, and weather conditions are known to affect rice yields. Here we discuss the impacts of climate change on several important rice diseases in Taiwan, focusing on the influence of variable weather conditions, higher carbon dioxide concentration, and differential nutrient deposition on the blast disease, bakanae disease, sheath blight, brown spot, and bacterial leaf blight of rice. In view of a higher risk of yield losses caused by these damaging diseases in the near future, we propose to conduct an integrated strategy combining resistance breeding, cultural practices, and coordinate monitoring for pest management. Disease severity can be significantly reduced if proper control measurements are applied the right way at the right time, with consideration of the progress of individual diseases in specific weather conditions. To strengthen food security in an era of climate change, future pest management should include the collection and maintenance of long-term weather data, and the improvement of timeliness and accuracy in disease forecasting. Understanding how different weather factors affect plant-pest interactions is also important. Research topics regarding the effects of individual environmental factors on the life cycles, sexual reproduction, adaptation, population dynamics, dissemination, evolution, and ecology of key pests should be further explored in depth."