Control methods of Maize Stem Rot

There are many causes of stem rot in corn production, the most important one is fungal stem rot, fungal stem rot is caused by a variety of pathogens single or compound infection caused by root and stem base rot disease, mainly caused by Pythium, anthrax, Fusarium, the symptoms on corn plants are different, let's take a look at the control methods of corn stem rot!

Symptoms of bacterial wilt stem rot

The root disease began at the filling stage of maize, and the peak period was from the late milk stage to the wax ripening stage. From the leaf of bacterial wilt to the wilt of the whole plant, it usually takes 5-7 days, the rapid onset only takes 1-3 days, and the long one can last more than 15 days. In the late stage of lactation, it often wilts and dies suddenly, and because the dead plants are turquoise, it is called bacterial wilt. First, it suffers from the roots. At first, the bacteria produce water-stained light brown lesions on the hairy roots, which gradually expand to the secondary roots, until the whole root is brown rotten, and finally the thick and thin roots become hollow. The cortex of the root is easy to peel off and loose, the whisker root and root hair are reduced, and the whole root is easy to pull out. Gradually spread to the base of the stem, the stem base 1-2 nodes began to appear water-stained fusiform or long oval spot, and then quickly become soft and sunken, the interior is loose, a pinch is shriveled, the feel is obvious. The internodes become light brown, the bracts of the ear are green and dry, the stalk is flexible, the ear is drooping, it is not easy to break away, the ear axis is soft, the grain is withered, and it is difficult to thresh.

Symptoms of bacterial stem rot

Bacterial stem rot mainly harms the middle leaf stem and leaf sheath. When there are 10 leaves of maize, water-stained rot appears on the leaf tip, and the diseased tissue begins to soften and give off a bad smell. The disease spot on the leaf sheath is irregular, and the edge is light reddish brown, especially at the junction of healthy tissue. When the humidity is high, the disease spot expands rapidly up and down, and in severe cases, the plant often folds above the disease part 3-4 days after the disease, and overflows the yellowish-brown rot bacteria liquid. The pathogen is stored on the diseased remains in the soil and invades from the stomata or wounds of the plant. The disease is serious when the wound is caused by high temperature and high humidity caused by pests.

Transmission of Maize Stem Rot

The pathogen may overwinter on the diseased remains in the soil and invade from the stomata or wounds of the plant the following year. When the corn is 60 cm high, the tissue is tender and prone to disease, and the wound caused by pests is conducive to the invasion of bacteria. In addition, pests carry pathogens to spread and inoculate at the same time, such as corn borer, cotton bollworm and other insect population, the disease is serious. High temperature and humidity is conducive to the disease, the average temperature is about 30 ℃, the relative humidity is higher than 70%, the average temperature is 34 ℃, and the relative humidity is 80% expanding rapidly. Low-lying terrain or poor drainage, excessive density, poor ventilation, excessive application of nitrogen fertilizer, frequent and serious wounds. Crop rotation, high border cultivation, good drainage and proper proportion of nitrogen, phosphorus and potassium fertilizer have strong plants and low incidence.

Control methods of Maize Stem Rot

1. Selecting resistant varieties: planting resistant varieties is the most economical and effective control measure, such as Zhengdan 958, Nongda 108, Ludan 50, Ludan 981 and so on.

2. crop rotation: planting corn in the same plot year after year can cause a large number of pathogens to accumulate in the soil, and the disease will be aggravated year by year. If rotation is carried out with non-host crops such as soybean and peanut, the occurrence of disease can be significantly reduced.

3. Strengthening the cleaning of the countryside: after corn harvest, timely removal of diseased plants and fallen leaves in the field and concentrated treatment can greatly reduce the accumulation of pathogenic bacteria and reduce the source of infection. Turning deep into the soil during autumn ploughing can also reduce and control the source of infection.

4. use coated seeds: high-quality seed coating agents contain not only fungicides, pesticides but also trace elements, which can not only resist pathogen infection, but also promote seedling growth and enhance disease resistance.

5. Strengthen cultivation management: do a good job of ploughing, soil cultivation and weeding in time to enhance root absorption capacity; low-lying land should pay attention to drainage in order to reduce field humidity and strengthen soil permeability, which is helpful to reduce the occurrence of diseases.

6. Chemical control: it was found that sporadic diseased plants could be sprayed or irrigated with 400 times metalaxyl or 500 times carbendazim, once every 7-10 days, and treated for 2-3 times, which had a better therapeutic effect.