The mycelium and attached conidia in the diseased leaf tissue remaining in the field surface and corn stover can be wintered and become the first source of infection in the second year. During the growing season of corn, spores are produced from the overwintering bacteria source, and spread to the corn leaves with rain or air current, which is suitable for germination and invasion under temperature and humidity conditions. After the invasion of the bacteria, it will expand rapidly. After about 14 days, it will cause local wilting, tissue necrosis, and then form dead plaque. Under humid climate conditions, a large number of conidia can be produced on the lesion, and it will be transmitted multiple times with the airflow. Reinfection, causing disease prevalence. Time to see the spot in the field: spring corn in early June, summer corn in mid-July. Control method Comprehensive control measures such as selection of resistant and disease-resistant varieties, strengthening of cultivation management, and key application of pesticides should be adopted. 1. Selection of resistant (resistant) disease varieties and maize hybrids resistant to large and small spotted diseases. 2. Implement a cropping system to avoid continuous cropping of corn, deep soil in autumn, deep burial of diseased plants, and elimination of sterilization sources; corn stalks used as fuel, processed early after spring, and can treat corn pupa early; Fully decomposed, straw fertilizer is best not applied in corn. 3, improve cultivation techniques, enhance corn disease resistance, early summer maize can significantly reduce the incidence, appropriate application of phosphate fertilizer, pay attention to the rational mix of nitrogen, phosphorus and potassium fertilizer, re-apply flare fertilizer, corn, soybean intercropping, or with wheat, peanuts Intercropping with sweet potato, wide and narrow planting; reasonable irrigation, low-lying attention to field drainage. 4. Spraying and controlling Because of the objective conditions such as high and dense planting of corn, it is possible to focus on the prevention and control of high-yield experimental fields such as cropping and intercropping. Generally, before and after the disease is expanded, it is possible to start spraying before and after the corn is squirmed. When the rate of diseased plants in the field is over 70% and the diseased leaf rate is about 20%. The most effective drugs are: 50% carbendazim WP, 50% carbendazim WP or 90% mancozeb, 500 times water, or 40% emulsified 800 times. 50 kg to 75 kg per acre of liquid medicine, spraying once every 7 to 10 days, a total of 2 to 3 times. Card Recognition Time Attendance Chongqing Huifan Technology Co., Ltd , https://www.hfsecuritytech.com