1.凤梨病。主要发生在苗期,蔗种感染后切口处变红,散有凤梨香味,逐渐变黑,病菌从切口向茎中心扩展,使蔗种形成空心,残留一束似头发状的维管束在其中。若种植感染的蔗种出苗后 Pineapple Mainly occurred in the seedling stage, sugarcane infection after the incision at the reddish, scattered with pineapple flavor, gradually black, bacteria from the incision to the stem center expansion, so that hollow cane form, leaving a bundle of hair like vascular bundle in them. If planted infected cane after emergence