What are the main diseases and insect pests of sweet corn?

What are the main diseases and insect pests of sweet corn? How to control the main diseases and pests of sweet corn are: corn borer, big. Leaf spot and sheath blight. First, the occurrence of diseases and insect pests: corn borer: moderate, local heavy occurrence. According to the investigation, the average injury rate of mature maize plants is 10.06%, and the average plant injury rate of serious fields is 31.43%. At present, the insect state in the field is mainly advanced instar larvae, with an average of 1971 larvae per mu and 2500 larvae per mu. Large and small spot disease: moderate and partial occurrence. The average diseased leaf rate of mature corn is 19.05%, which is as high as 30%; the average diseased leaf rate of maize at seedling stage is 42.86%, and the high rate is 60%. Sheath blight: mild and locally severe. The average rate of diseased plants was 10%, and the number of recurrent fields reached 93.33%. 2. weather forecast for occurrence trend analysis. According to the weather forecast, there was still one tropical cyclone affecting our city in September, and the rainfall in most areas was the same as that in previous years, and in some areas it was 10-20% more than that in previous years, 100-200 mm. At present, there is a great difference in the growth period of corn in the field, and the abundant food is beneficial to the damage of pests. It is expected that the next stage of corn borer will be more serious, and the suitable control period of the next generation of corn borer will be from September 10 to 15. Leaf spot and sheath blight will occur moderately and locally. 3. Control opinions (1) due to the different planting periods of corn in different places, it is necessary to formulate control strategies according to local conditions and guide timely prevention and control. (2) to carry out comprehensive prevention and control with the combination of agricultural control, physical control and chemical control. Strengthen field management, remove stagnant water in the field in time, remove branches, leaves and remains of diseases and pests, and concentrate on deep burial or destruction; do a good job in fitness cultivation to improve the disease resistance of plants; use insecticidal lamps to trap and kill adults of corn borer in areas with conditions. reduce the density of insect population and the number of eggs in the field. (3) Chemical control should be carried out in a timely manner with high-efficiency and low-toxic agents. If the medicine is applied in case of rain, make up the medicine in time. Corn borer: pay attention to the prevention and control of corn borer egg hatching peak, heart leaf end (trumpet mouth) and heading stage. At the peak of egg hatching, 1.8% avermectin was sprayed with 1000-fold solution; at the end of heart leaf (trumpet mouth), 1.8% avermectin 800x solution or BT wettable powder 100g 200g mixed with fine sand 3.5kg was applied to trumpet leaves; at heading stage, 80-1000 times of 90% trichlorfon or 50% phoxim EC was used to spray the ear or infuse the filament base at the top of the female ear. Large and small spot: you can choose 70% methyl topiramate wettable powder 1000 times liquid spray, or 10% high water dispersible granule 1000 times liquid spray, once every 7-10 days, 2-3 times continuously. Sheath blight: the stem base and leaf sheath were sprayed with 600 × 800 times of 70% methyl topiramate or 50% carbendazim wettable powder, and the diseased leaf sheath was stripped off after the jointing stage, burned out from the field, and cut off the route of re-infection. Note: pesticide application should be stopped 10-15 days before sweet corn harvest to ensure food safety. Click to get more corn planting techniques click to get more food crop planting techniques