What are the common diseases and insect pests in corn

The common diseases and insect pests in corn are corn borer, armyworm, cotton bollworm, aphid, corn leaf mite and so on. Control methods: spraying plants with 2.5% cyhalothrin 2000-2500 times solution can control Lepidoptera pests such as corn borer, armyworm and cotton bollworm, and 3000 times solution of 2% avermectin can control corn leaf mites. 3000-fold solution of 2% avermectin can effectively control corn aphids, gray planthopper and so on.

Corn borer

1. Corn borer, also known as heart borer, belongs to Lepidoptera and Pyralidae, which is a common pest in corn. It can harm all parts of corn plants. Corn borer generally has 2-4 generations in the whole year, especially in areas with low altitude and high temperature.

2. Adults generally like to be active at night, have a strong ability to fly, have phototaxis, have a life span of 5-10 days, and like to lay eggs on both sides of the midrib on the back of the luxuriant corn leaves above 50cm.

3. After hatching, the corn borer larvae gather together at first, then crawl in the young part of the plant and begin to harm the corn plant. the newly hatched larvae can spin and droop and drift to the neighboring plants with the help of the wind, causing harm to the neighboring plants.

2. Armyworm

1. Armyworm, also known as wheat silkworm and colorful worm, belongs to the family Lepidoptera. It is a common pest of food crops and forage crops, which harms corn seriously. Armyworm is a kind of migratory, polyphagous and fulminant pest.

2. The occurrence of armyworm is closely related to temperature and humidity. Generally, the suitable temperature for adults to lay eggs is 19-25 ℃. When the temperature is above 30 ℃, the spawning will be affected.

3. The higher the humidity is, the more favorable it is for adults to spawn, especially in the cloudy and sunny climate, rainy and humid climate, it is more conducive to adult oviposition, egg hatching and larval development.

3. Cotton bollworm

Helicoverpa armigera belongs to Lepidoptera and Noctuidae, also known as green worm, drill worm, cotton boll armyworm and so on.

4. Aphids

Corn aphids can harm a variety of gramineous crops and weeds, mainly as adult aphids and nymphs on corn heart leaves at seedling stage, and mainly harm ears after heading, absorb corn juice, hinder its growth and development, and spread a variety of cereal viruses. Its secretions will stick pollen and affect corn powder, in addition, it will also spread corn dwarf mosaic virus disease, resulting in a reduction in corn yield.

5. Corn leaf mite

Corn spider mites, also known as red spiders, do harm to many kinds of crops, mainly by adult mites and nymph mites to suck the sap from the back of the host leaves, and the leaves of the affected crops will change from yellow to white and die, which will seriously affect the filling process of corn and reduce the yield.

VI. Prevention and control methods

1. Spraying corn plants with 2000-2500 folds of 2.5% cyhalothrin, or 1000-2000 folds of 20% fenozide suspension, or 1500-2000 folds of 25% diflubenzuron, can effectively control Lepidoptera pests such as corn borer, armyworm, cotton bollworm and so on.

2. Spraying corn plants with 3000 times liquid 2% avermectin can effectively control corn red spiders.

3. Spraying corn plants with 1500 times solution of 3% acetamiprid or 3000 times solution of 2% avermectin can effectively control corn aphids, gray planthopper and so on.

4. In the corn trumpet period, 30% phoxim granules can be used, 0.25 kg per mu plus 2 kg of fine sand to stir evenly, and 2-3 grams can be applied to each plant, which can effectively control corn borer.