台灣水稻細菌性病害之發生與防治

Abstract

我國水稻細菌病害以白葉枯病、細菌性穀枯病及細菌性條斑病為主。嚴重時均可造成重大經濟損失。白葉枯病有三種病徵型，分別是葉枯型，急性萎凋型及淡黃化型。白葉枯病菌可由傷口或自然開口侵入，高溫多濕，高氮肥的環境下易發生，造成葉片枯萎，植株死亡，進而影響水稻產量與品質，白葉枯病菌可在稻樁、再生稻、部分野生稻與禾本科雜草上存活，也可在種子上存活，再經由風、雨或人為機械傳播。細菌性穀枯病主要為害榖粒，高溫多濕條件下易發病，嚴重者可造成一半以上或全穗穀粒枯死，穀枯病可藉由風、雨和稻種傳播，在台灣中南部二期稻作抽穗期發生較普遍。細菌性條斑病會在稻葉上產生水浸狀半透明病斑，受葉脈限制而成條斑狀。病菌由自然開口或傷口侵入，在高溫多濕、高氮肥的環境下易發生，影響水稻產量與品質，病原菌可在病株殘體、帶病種子與野生稻上存活，可經由雨水、灌溉水、昆蟲、農事操作、葉片接觸和帶病之野生稻作近距離傳播，而帶病的種子作可作遠距離傳播。針對以上三種細菌性病害的防治方法歸整如下：(1)抗病育種，(2)稻種消毒，(3)田間管理，(4)藥劑防治及，(5)非農藥防治等。 Rice cultivation is the most important agriculture in Taiwan. Several bacterial diseases could be found in Taiwan. Among them, bacterial blight（Xanthomonas oryzae pv. oryzae）, bacterial leaf streak （Xanthomonas oryzae pv. oryzicola）and grain rot ( Burkholderia glume ) were the most significant and caused great economic losses in Taiwan. Bacterial leaf blight is one of the devastating disease of rice, which is also known worldwide. There are three types of symptoms : leaf blight, “kresek” and pale-yellow in Taiwan. Now the disease is prevalent and is responsible for 6 – 60% yield reductions depending upon its severity. Leaf streak is mainly occurred in Asian countries, northern Australia, and West Africa and is responsible for 10 – 60% yield reductions. Grain rot of rice is a seedborne disease and in severe case could cause severe loss while in nursery bed. These bacterial diseases might be transmitted through contaiminated seeds, rain splash, irrigation water, insects and culture practices. Bacterial diseases are long known difficult to manage and resistant varieties are the most effective tool to control. However, several measures such as seed quarantine, good field hygiene, and pesticides application could provide ideal outcome. In the coming future, to develop environmental friendly control strategies for organic rice growers and to develop technologies for good nursery bed hygiene are urgently needed.