烟草赤星病是烟草生育后期的一种真菌性病害。近年来危害日益严重,使烤烟质量下降1—2个等级,已成为优质烟生产的一大障碍。 1.症状 病菌主要为害叶片。初期为黄褐色小斑点,后逐渐扩大为直径1—2厘米的圆形或不规则形病斑,周围有黄色晕圈,经多次扩大,形成多重同心轮 Tobacco brown spot disease is a fungal disease later in tobacco growth. In recent years, the increasingly serious harm to the flue-cured tobacco quality decline 1-2 levels, has become a major obstacle to high-quality tobacco production. 1. Symptoms of the main damage to the leaves of bacteria. The initial small brown spots, and gradually expanded to a diameter of 1-2 cm round or irregular lesions, surrounded by yellow halo, after repeated expansion, the formation of multiple concentric wheels