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稻瘟病是我省有水稻产区的主要病害之一。根据稻瘟病原菌危害水稻的不同时期和部位,分为苗瘟、叶瘟、穗颈瘟和谷粒瘟。对产量影响较大的是叶瘟和穗颈瘟。 叶瘟多发生在水稻分蘖期、拔节期及幼穗形成期。叶片上典型病斑呈梭形,病斑中心灰白色,外层四周黄褐色,病斑两端有褐色坏死线向外延伸成长条状,潮湿时,病斑背面也产生灰绿色霉层。 穗颈瘟发生在穗颈上,病斑初呈水渍状淡褐色小点,后逐渐围绕颈、穗轴扩展,并逐渐向下发展。穗颈瘟发病早的多形成白穗,发病晚的稻粒不充实。 叶瘟一般从7月上旬开始,7月下旬达到高峰。穗颈瘟从8月中旬开始,8月下旬至9月上旬为发病高峰期。各地因气温、地势、湿度、栽培措施及品种不同,发病轻重也不一样。水稻生长繁茂、施用氮肥过多过晚、
Rice blast is one of the main diseases in rice producing areas in our province. According to rice blast pathogens endanger the rice at different stages and parts, divided into seedling blast, leaf blast, panicle blast and grain blast. The greater impact on the yield of leaf blast and panicle blast. Leaf blast occurred in the tillering stage of rice, jointing and panicle formation period. The typical lesions on the leaves are fusiform, the lesion center is gray, the outer layer is surrounded by yellowish brown, the brown necrosis line extends outwards to form long strips at the two ends of the lesion. When wet, the back of the lesion also produces gray-green moldy layer. Panicle blast occurred in the panicle neck, the lesion was light brownish-brown spots at the beginning, then gradually around the neck, cob expansion, and gradually downward. Early onset of panicle blast disease formed white ear, late onset of rice grain is not full. Leaf blast generally start in early July, peaked in late July. Pancreatic head blast from mid-August, late August to early September as the peak incidence. Due to temperature, topography, humidity, cultivation practices and varieties vary, the incidence is not the same. Rice lush growth, excessive nitrogen fertilizer too late,