Symptoms During the middle and late grain filling stage, mungbean-sized black-brown patches were produced on the upper middle leaf sheath or temporal lobe, and some were slightly purplish. Afterwards, irregular or near-circular purple spots were produced on leaf sheaths and pods. The pathogenic Ascochyta zeae Stout is called as S. zeae, a fungus belonging to the fungus Aspergillus. Conidiospores buried in diseased leaves or stem tissues, membranous, with shallow basement, with orifices; conidia bicellular, colorless or sometimes lightly coloured, size 8.5–13 .53-4.5(um). The disease is related to clusters of aphids in the sheath. In particular, when the weather turns cold, the sugar liquid and the excreta discharged from the aphid are mixed and moldy, resulting in the appearance of plaque on the outside, and the aphid breeds rapidly in the leaf sheath. Transmission routes and pathogenic conditions The pathogens are kept in the soil by conidiospore, mycelia lurking in the diseased tissue and wintering, and the roosting robes are produced in the following year for initial infection. After the onset of the disease, the diseased part also produces conidia to re-invade. dye. In July and August, the temperature is high and locust occurrence is conducive to the occurrence and expansion of the disease. Preventing and controlling methods to prevent aphid from transferring to leaf sheath before tasseling is the key to prevention of sheath spot disease. Specific methods see food crop pests. Peeled Onions,Fresh Peeled Onions,Peeled Fresh Red Onion,Fresh Yellow Onion Peeled Yirun Agricultural Cooperative , https://www.yiruncn.com