水稻恶苗病是一种真菌病害,近几年来有回升的趋势。此病不但危害秧田,也危及大田。 1.发病症状 秧田期发病,秧苗纤细瘦高,要比正常苗高30％左右。植株淡绿色,叶片比正常苗略窄,根稀少发育差。严重受害的秧苗,若不及时防治,大多在移栽后不久便死亡。大田期发病,多发生在移栽后10—30天,病株高瘦,不分蘖或分蘖极少,节间加长,节部生出大量须根,基部节上尤多。 2.发病特点 此病以种子传播为主,稻草上也能带菌安全越冬。播种以后,病菌从 Bakanae is a fungal disease that has been on the rise in recent years. The disease not only endanger seedling, but also endanger the field. 1. Morbidity symptom onset disease, thin slender seedlings, about 30% higher than normal seedlings. Light green plants, leaves slightly smaller than normal seedlings, sparsely developed sparsely. Seriously damaged seedlings, if not timely control, most of them died soon after transplanting. Field incidence, occurred in 10-30 days after transplanting, the diseased plants are tall and thin, with no tillers or few tillers, internodes are lengthened, nodes produce a large amount of fibrous roots, and basal nodes are especially large. 2. The incidence of the disease spread to the main seed, straw can also carry safe overwintering. After sowing, the bacteria from