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烤烟是云南省主要经济作物之一,病害发生危害较重的主要有赤星病、黑胫病和青枯病等。一、烟草赤星病。本病以病原孢子及菌丝体在病残体上越冬,次年借风雨传播侵染。4-5月在苗床即已发生,7-8月收获期中遇多雨、日照少、相对湿度高,病害发生普遍严重。病状:病害发生在叶部,叶上病斑稍大,圆形或不规则形,呈浓褐色,重轮状,后在中心部稍褪色,病斑质脆,常由此生裂孔。此病特征即是病斑呈浓褐色的重轮,后破裂成孔为其特征。防治:①避免施
Flue-cured tobacco is one of the main cash crops in Yunnan Province. There are mainly brown spot diseases, black shank and bacterial wilt. First, tobacco brown spot disease. The disease to pathogenic spores and mycelium overwintering in the sick residual body, the following year by the spread of infection spread. 4-5 months in the seedbed that has occurred, July-August harvest in the event of rain, sunshine, high relative humidity, disease occurred generally serious. Symptoms: disease occurs in the leaves, leaf lesions slightly larger, round or irregular shape, was dark brown, round shape, slightly faded in the center, diseased plaque, often by this Health hole. The disease is characterized by a dark brown lesions of the wheel, after the hole into the broken features. Prevention: ① to avoid Shi