Prevention of Common Pests and Diseases After Sowing Summer Corn and Selection of Herbicides
During corn cultivation, after sowing and emergence is a period of high incidence of various diseases and pests. Among them, underground pests such as white grubs, mole crickets, wireworms, and small cutworms, as well as the two-spotted armyworm (Athetis lepigone), armyworms, cotton bollworms, thrips, and seedling blight are especially serious. For this reason, if you want to manage the seedling emergence period well, you need to carry out prevention in advance. So what are the common pests and diseases after sowing summer corn? How should they be prevented? What medicine is good for weed control?
Common pests and diseases:
1. Corn seedling blight: it can be controlled by spraying with 50% carbendazim wettable powder at 800 times dilution, or 10% difenoconazole suspension concentrate at 1500 times dilution.
2. To control thrips, planthoppers, armyworms, corn borers, cotton bollworms, etc.: spray with 2.5% lambda-cyhalothrin or 5.7% emamectin benzoate water-dispersible granules at 1500 times dilution plus 12% abamectin·thiamethoxam suspension concentrate at 1000 times dilution.
Prevention methods:
1. Promptly remove wheat straw and wheat chaff from the field: after wheat harvest, through measures such as clearing straw and wheat chaff from the field and sowing rows, ecologically control damage by the two-spotted armyworm (Athetis lepigone).
2. Chemical weed control.
(1) For corn fields sown after stubble removal, soil closure treatment should be carried out 1-3 days after sowing: use 48% butachlor·atrazine suspension concentrate at 250-300 ml per mu, or 40% propisochlor·atrazine suspension concentrate at 250-300 ml, mixed with 30 kg of water and sprayed evenly on the ground.
(2) For corn fields sown on stubble, 1-3 days after sowing, 65% glyphosate soluble powder at 150-200 g can be mixed with a soil-closure herbicide and sprayed, “one application, both killing and sealing”.
(3) At the 2-10 leaf stage of corn, use 20% nicosulfuron + 2% atrazine (safened type) suspension concentrate at 200 ml per mu, or 4% nicosulfuron (safened type) suspension concentrate at 100 ml, mixed with 15 kg of water, and spray on stems and leaves.
Precautions for herbicide use:
(1) There are many types of herbicides for corn fields. Pay attention to distinguishing them when applying, and apply according to the recommended dose to avoid herbicide damage.
(2) When applying, walk backward or walk in straight side-to-side lines, and spray evenly to prevent missed spraying and repeated spraying. If using a self-propelled boom sprayer, service the machine in advance, pay attention to the application dose, and prevent missed spraying and repeated spraying.
(3) Do not apply during the high-temperature period at noon, to avoid herbicide damage. Generally, spray before 9 a.m. or after 5 p.m. in windless weather. Avoid herbicide droplet drift causing damage to nearby cotton, vegetables, and other crops.
(4) For post-emergence stem and leaf treatment, control weeds before the 3-leaf stage to ensure the control effect. When directed spraying between corn rows, a protective shield must be added to the nozzle. When the weed plants are relatively tall, first push the weeds down with an iron rake and then carry out directed spraying. The effect is better and it is less likely to damage the corn plants.
(5) Spraying nicosulfuron or agents containing nicosulfuron can easily cause herbicide damage to some corn varieties, such as the Denghai series, so use caution when applying. Organophosphorus pesticides are prohibited within 7 days before and after application.