What are the common pests and diseases in corn cultivation?
SummaryCommon corn pests and diseases include: Asian corn borer, armyworm, cotton bollworm, aphids, corn leaf mite, etc. Control methods: use 2.5% lambda-cyhalothrin 2000-2500 times dilution to spray the plants, which can control lepidopteran pests such as Asian corn borer, armyworm, and cotton bollworm; use 2% abamectin 3000 times dilution to control corn leaf mite; use 2% abamectin 3000 times dilution to effectively control corn aphids, small brown planthopper, etc.
I. Asian corn borer
1. The Asian corn borer, also known as the stem borer, belongs to the order Lepidoptera, family Crambidae, and is a common corn pest. It damages all aboveground parts of the corn plant. The Asian corn borer generally has 2-4 generations per year, and in areas with low altitude and high temperatures, there are more generations.
2. Adults generally prefer to be active at night, have relatively strong flying ability, are phototactic, and live for 5-10 days. They prefer to lay eggs on both sides of the midrib on the underside of lush corn leaves more than 50 cm above the ground.
3. After the Asian corn borer larvae hatch, they initially gather together, then crawl on the tender parts of the plant and begin to damage the corn plant. Newly hatched larvae can spin silk and hang down, and with the help of wind, drift to neighboring plants, causing damage to neighboring plants.
II. Armyworm
1. The armyworm, also known as the wheat silkworm or five-colored worm, belongs to the order Lepidoptera, family Noctuidae. It is a common pest of food crops and forage crops, and causes relatively serious damage to corn. The armyworm is a migratory, polyphagous, outbreak-prone pest.
2. The occurrence of armyworm is greatly related to temperature and humidity. The suitable temperature for adult egg-laying is generally 19-25°C, and when the temperature reaches above 30°C, egg-laying is affected.
3. The higher the humidity, the more favorable it is for adult egg-laying, especially under alternating cloudy and clear, rainy and humid weather, which is more favorable for adult egg-laying, egg hatching, and larval development.
III. Cotton bollworm
The cotton bollworm belongs to the order Lepidoptera, family Noctuidae, and is also known as the green worm, stem borer, cotton boll noctuid, etc.
IV. Aphids
Corn aphids can damage a variety of gramineous crops and weeds. Mainly at the seedling stage, adult aphids and nymph aphids gather on the corn whorl. After heading, they mainly damage the ear, absorb corn sap, hinder its growth and development, and also transmit various gramineous cereal viruses. Their secretions stick to pollen, affecting corn pollination. In addition, they also transmit maize dwarf mosaic virus disease, causing corn yield reduction.
V. Corn leaf mite
The corn leaf mite, also known as the red spider, damages many types of crops. It mainly uses adult mites and nymph mites to pierce and suck the sap of the host leaf back tissue. The leaves of damaged crops change from yellow to white and die, seriously affecting the corn grain-filling process and leading to reduced yield.
VI. Control methods
1. Use 2000-2500 times dilution of 2.5% lambda-cyhalothrin, or use 1000-2000 times dilution of 20% tebufenozide suspension concentrate, or use 1500-2000 times dilution of 25% diflubenzuron, and spray the corn plants to effectively control lepidopteran pests such as Asian corn borer, armyworm, and cotton bollworm.
2. Use 3000 times dilution of 2% abamectin and spray the corn plants to effectively control corn red spider.
3. Use 1500 times dilution of 3% Tianda acetamiprid, or 3000 times dilution of 2% abamectin, and spray the corn plants to effectively control corn aphids, small brown planthopper, etc.
4. At the corn large trumpet stage, use 30% phoxim granules, 0.25 kg per mu plus 2 kg of fine sand, mix evenly, and apply 2-3 grams per plant, which can effectively control the Asian corn borer.