Corn pest control technology

Today I will tell you about the main corn pest control technology, which is very important.

1. Corn stalk rot

Symptoms: Sweet corn stalk rot is often caused by several fungi and bacteria alone or in combination. It usually occurs in the late silking stage of sweet corn. The symptoms are divided into acute and chronic types. The acute type, also known as the "wilt type", often appears after a storm or when there is strong wind. After 2 to 3 days, the leaves lose water and become withered. The chronic type progresses slowly, with the leaves gradually turning yellow from bottom to top. In the later stage, the base of the stem changes color and decays, and the infected part rots with a rotten smell. The plant withers and the diseased part is like waterlogging. The pith is hollow and prone to lodging. The cobs droop and the grains are shriveled.

Pathogen: Erwinia bacteria. Transmission route: The pathogen spends the winter on the soil surface with the remains. The pathogen can invade through wounds or directly. Or invade the stem from the base of the leaf sheath and spread to the lower internodes. It can also be transmitted by seeds. The disease is more serious when the temperature is high and humidity is 30℃, the air in the field is not circulated, and the soil drainage is poor.

Prevention and control: (1) Breed disease-resistant varieties; (2) Crop rotation and reasonable planting density; (3) Scientific fertilization; (4) Chemical control: Spray the stem base with 1000 times of Cypermethrin and irrigate the roots with 1000 times of Cypermethrin or Cypermethrin.

Corn pest control methods

2. Corn bacterial wilt

Pathogen: Mastigomycetes, Pythium spp.

Symptoms: The whole corn plant withers and dies during the jointing stage. If the base of the stem is cut open, the pith will turn brown. In the later stage of the disease, Fusarium will be present.

Prevention and control methods: Root irrigation with 1000 times of Jinleidomil, 1000 times of Kangzhenglei or 1000 times of Gaike.

3. Corn Sheath Blight

Dirty green, oval, cloud-like spots appear on the leaf sheath, which are like scalds caused by boiling water. Later, the spots gradually increase and connect to form a large irregular cloud pattern, and then spread to the upper leaf sheath and leaves. In severe cases, they can harm the top leaves. Pathogen: Caused by corn sheath blight, a fungus.

Prevention and control methods: Spray 1000 times of Naszin, 800 times of Dakonin, 1500 times of Vogelin or 1000 times of Shibaigong.

4. Corn leaf spot

Symptoms: Mainly damage leaves, stems, ears, seeds, etc. The lesions are oval, rectangular or spindle-shaped, yellow-brown or gray-brown. Sometimes the lesions have ring patterns. Under high temperature conditions, the lesions appear dark green infiltration areas, and the lesions appear as yellow-brown necrotic spots.

Pathogen: It is called Zea mays planus, which belongs to the subdivision of Ascomycota. Its sexual stage is called Coccidiophore, which belongs to the subdivision of Ascomycota.

Transmission route: The disease is more severe when the temperature is above 25 degrees and there are many rainy days.

5. Corn leaf spot

It mainly harms leaves, and in severe cases, it affects leaf sheaths and leaf sheaths. In the field, the disease starts from the lower leaves and gradually spreads upward. In the early stage of the disease, it appears as water-soaked blue-gray spots, which then spread to both sides along the leaf veins, forming large spindle-shaped or fusiform spots with yellow-brown centers and dark brown edges. When the humidity is high, the spots heal into large pieces, and black-gray mold-like substances appear on the spots. The diseased parts crack longitudinally or wither and turn yellow. The ear sheaths are infected, and the spots are irregular.

Conditions for the disease: Temperature of 18-22℃, high humidity, especially rainy, foggy or continuous rainy weather, can cause the disease to spread.

Pathogen: It is called Helminthosporium macrospotum, which belongs to the subphylum Ascomycota.

Prevention and control methods: Before the outbreak, use 500-600 times of Surun, spray once every 15-20 days, and spray three times in a row; Amisida 1500-2000 times can achieve the effect of prevention, treatment and eradication; for treatment, you can use 1500-2000 times of Shibaxin or Shibagong, 1000 times of Nasru or 5000-7000 times of Tefulin spray.

6. Corn smut (corn smut)

Symptoms: Also known as corn black disease, it can occur in all growth stages, especially in the heading stage. Tumors of varying sizes appear on the affected parts. In the early stage, the tumors are covered with a white film, which later turns gray. The tumors are rich in water and emit black powder after drying and cracking, which is the pathogen spores. Bean-sized tumors are easy to appear on the leaves. Galls appear on the male spikes, and large tumors form on other parts.

Pathogen: It is called Ustilago maydis, which belongs to the Basidiomycetes.

Transmission route: Spores are spread by wind, rain and insects. The disease is prone to occur in high temperature, drought or excessive nitrogen fertilizer.

Prevention and control methods: Sweet corn is susceptible to disease, so it is especially important to select disease-resistant varieties. Severely diseased fields should be rotated for 2-3 years. When diseased tumors appear in the field, they should be cleaned and buried in time, and deep plowing should be done in time to reduce the source of disease. Chemical control: Spray 1500 times of Hexagon or Hexagon, 1000 times of Hexagon, 1000 times of Naszin, or 800 times of Triadimefon.

7. Head smut

Black silk disease is a systemic disease that harms the male and female ears of corn. Some affected plants are dwarfed, some have multiple tillers, and some have clusters. The inflorescence of the male ear is completely or partially deformed, forming a tumor, which is covered with a white film on the outside and contains agglomerated black powder, i.e., thick-walled spores. Except for the bracts, the female ears are all turned into a mass of black powder, with many tangled residual parasitic tissues inside. If one plant is infected, all the ears and latent ears will be infected.

Chemical control: Seed disinfection: (1) Mix seeds with 1000 times of Celexa, (2) Soak seeds with 1500 times of Celexa. Soil disinfection of nutrient cup soil: Mix 1 kg of Bisumei with 10,000 kg of nutrient soil, sprinkle water to keep the soil moisture content at 20-25%, cover the soil with plastic film for one week, then remove the film to release air for one week, and then put it in the cup for sowing.

8. Corn rust

It mainly harms corn leaves. In the early stage, small yellow to orange-yellow raised pustule-like spots appear on the leaves. In the later stage, the epidermis of the spots ruptures and yellow to yellowish-brown powder is released, which is the spore pile. In severe cases, the spots are spread all over the leaves, emitting rusty powder, and the growth of the leaves is hindered.