How to control pests and diseases during the sowing and seedling stages of corn?

Seed treatment

Treating corn seeds before sowing can increase the germination rate, promote seedling growth, and also kill pathogens on the seed coat, reduce pest and disease damage, and promote full stands, healthy seedlings, and strong seedlings. Seed treatment methods include:

1. Sun-drying seeds: Spread the selected seeds on the ground or on a mat, 5-6 cm thick, and turn and sun-dry them continuously for 2-3 days. Never spread the seeds directly on cement or metal sheets, to avoid scalding the seeds due to excessively high temperature.

2. Chemical seed dressing: To control corn viral disease, use 100 ml of 1.5% Zhiblingling II, add an appropriate amount of water, and dress 50 kg of corn seed. To control root rot and smut, use 100-150 g of 50% carbendazim or 25% triadimefon wettable powder to dress 50 kg of seed; to control underground pests, use 100 ml of 50% phoxim emulsifiable concentrate, add an appropriate amount of water, and dress 100 kg of corn seed. Mix well, let dry, and then sow. Where underground pests and corn diseases occur together, a mixed pesticide combination can be used for seed dressing. When dressing seeds, first mix the insecticide, and after drying, mix the fungicide.

3. Coating with a dedicated seed coating agent. The dosage is 50 ml to coat 5-7 kg of seeds, which both prevents disease and controls insects.

Seedling-stage control measures

1. Corn weed control

Controlling weeds can reduce breeding sites for pests and diseases. Choose a high-quality and suitable herbicide, grasp the optimal application period, appropriately increase the amount of water when spraying, avoid high-temperature and windy weather, and spray evenly onto the ground without repeated spraying or missed spraying. Strictly follow the herbicide instructions to prevent phytotoxicity. Commonly used herbicides include: 1. Use 150-200 ml of 40% acetochlor-atrazine mixture per mu, diluted with 50-80 kg of water, and spray after corn sowing and before emergence. 2. Use 80-100 ml of 18% nicosulfuron per mu, diluted with 50-80 kg of water, and spray directionally at the 2-3 leaf stage of corn. 3. Use 150 ml of 50% acetochlor-atrazine mixture per mu, diluted with 50-80 kg of water, and spray directionally before the 4-leaf stage of corn.

2. Pest and disease control at the seedling stage:

(1) Small brown planthoppers and aphids are virus-transmitting insects of corn. Spray with 1000-fold dilution of 10% imidacloprid.

(2) To control corn viral disease: at the one-leaf-one-heart stage of corn, use 800-1000-fold dilution of 1.5% Zhiblingling II per mu, spray once every 7-10 days, for 2 consecutive times, spraying evenly on both sides of the leaves.

(3) Pay attention to the occurrence of armyworms and prevent armyworms from damaging after wheat lodging. Because armyworms are a migratory pest, close attention should be paid to their occurrence dynamics. Before the third instar of armyworm larvae, when transparent small spots appear on the corn whorl leaves, apply pesticide for control. You can use 25% diflubenzuron suspension concentrate or NPV virus preparation at 30-50 g per mu, diluted with 40-50 kg of water for spraying, and it can also simultaneously control pests such as caterpillars and cotton bollworms. The spraying time should be based on the armyworm's habit of hiding by day and coming out at night, choosing before 10 a.m. and after 4 p.m.