What medicine did corn get stalk rot disease to use? What are the prevention methods?

Maize stem rot is a disease caused by single or compound infection of many kinds of bacteria, which mainly harms the stalk and leaf sheath of maize plants. Generally speaking, the decay of the disease but no stench is mostly caused by saprophytic fungi; the odor is mostly caused by bacteria, or by the mixed infection of saprophytic fungi and bacteria. So what kind of medicine does corn use when it gets stem rot? What are the prevention and control methods?

Analysis on the symptoms and causes of Maize Stem Rot

Stem rot generally occurs from the filling stage of corn, and the peak stage is from milking to wax ripening. The pathogen invaded from the root system and spread in the plant. The primary and secondary roots of most diseased plants were necrotic and turned red and green, especially when it was sunny after rain, wilting and wilting were more obvious.

Maize stem rot is characterized by stem rot in seedling stage and bacterial wilt in mature stage, so it is also called maize bacterial wilt.

1. Maize stem rot (maize bacterial wilt)

(1) symptoms. Maize stem rot mainly infects the root and stem base of maize, and the pathogen invades from the root system and spreads in the plant. During the root cutting or stem base examination at the seedling stage, it was found that the xylem turned brown, and the primary and secondary roots were necrotic and rotten, resulting in root and stem base rot, lodging or whole plant death. The aboveground part showed that the edge of the middle and lower leaves turned yellow and brown, and the leaves of the whole plant turned yellow seriously. The peak of maize stem rot was from late milking stage to wax ripening stage. The diseased plant initially showed wilting, the leaves of the whole plant suddenly faded and had no luster, and the leaves became bluish gray and withered from bottom to top, showing symptoms of wilt. Some diseased plants showed acute symptoms, that is, the whole plant suddenly withered at the end of milk or wax maturity, and there was no obvious process of gradual development from bottom to top, which was more common when it was sunny after rain. It takes about 1 week to show the disease from the first diseased plant to the whole plant, the short one only takes 1-3 days, and the long one can last more than 15 days. The hollow part of the root and stem base of the diseased plant became soft, and it was easy to collapse in case of wind. After breaking, the stem pulp tissue became brown and decomposed, the whisker root decreased, and it was easy to pull up; the ear was drooping, the ear stalk was flexible, it was not easy to break off, the grain was not glossy and gray, and the arrangement was loose and easy to thresh.

(2) Analysis of the causes. Maize stem rot is a kind of important soil-borne fungal disease caused by several kinds of Fusarium or Rhizopus, which is mainly caused by soil bacteria and infects the main root. The pathogen overwinters on the diseased tissue in the soil and invades from the stomata or wounds of the plant the following year. The disease at seedling stage is mainly due to soil hardening and poor permeability caused by sowing of corn stubble, or due to poor fertility, excessive drought or waterlogging, and excessive residue of herbicides in soil, it is easy to cause poor root system development, weak growth potential and reduced disease resistance of seedlings. in the middle stage of corn growth, the corn grows rapidly, the tissue is tender, and it is also susceptible to disease. The occurrence of bacterial wilt in maize near maturity, on the one hand, is related to the disease resistance of the variety itself, on the other hand, it is closely related to the climatic conditions at that time, coinciding with the high temperature and rainy year, especially when the rainstorm suddenly clears up, the disease may be epidemic. Because from the middle filling stage to the wax ripening stage, continuous rain, insufficient light, heavy overcast and sunny are the most favorable conditions for the occurrence of bacterial wilt; excessive nitrogen fertilizer application, over-dense planting, field closure, poor ventilation and light transmission and various damage to the plant will aggravate the disease; in the continuous cropping land of corn, the number of pathogens accumulated in the soil is large, and the disease is serious. Low-lying cornfields with stagnant water can also easily lead to disease.

two。 Maize bacterial stem rot

(1) symptoms. The bacterial stem rot of maize began to occur before the big trumpet stage when there were more than 10 leaves of maize. firstly, irregular water-immersed disease spots appeared on the leaf sheath and stem in the middle and lower part of the plant, and the pathogen infected the stem and heart leaf in the process of infecting the stem and heart leaf. cause tissue necrosis at the growing point. Rot, heart leaves chlorosis and wilting, easy to pull out, resulting in tissue softening, decay, and emitting a fishy smell. The diseased plant is easy to break from the diseased part, can not heading or fruiting, the general incidence rate is equivalent to the loss rate.

(2) Analysis of the causes. Bacterial stem rot of maize is a highly harmful disease newly discovered in recent years, which is caused by torrential rain. Maize bacterial stem rot is a destructive disease caused by bacterial infection. The pathogenic bacteria overwintered on the diseased remains in the field and became the main source of primary infection in the second year. In the field, germs spread with air currents and wind and rain. The pathogen mainly invades from the wound and the leaf sheath. High temperature, high humidity, continuous rain, hot water irrigation or muggy after rain are favorable conditions for the occurrence and spread of the disease. The temperature was 2830 ℃, the relative humidity was more than 80%, and the temperature was 34 ℃. The disease spread most rapidly. When the temperature dropped below 26 ℃, the disease stopped developing. In the first and middle of July, the weather in our city was hot and rainy, humid and muggy, and the leaf sheath was stagnant, which was most conducive to bacterial infection. The soft tissue of corn is prone to this disease when the 60cm is high, and the wound caused by pests is also beneficial to the invasion of bacteria. In addition, pests not only carry germs, but also play a role in transmission and inoculation, such as corn borer, cotton bollworm and other insect population, the disease is serious. The disease of corn continuous cropping land is serious because of a large number of bacteria in the soil. Low-lying terrain or poor drainage, excessive density, poor ventilation, excessive application of nitrogen fertilizer, too many wounds and serious disease. The plot with good rotation, good drainage and proper proportion of nitrogen, phosphorus and potassium fertilizer has strong plants and low incidence.

Control measures of Maize Stem Rot

In the face of maize stem rot disease, we should take comprehensive control measures, such as selecting resistant and disease-tolerant varieties, strengthening cultivation management, focusing on pesticide protection and so on.

The main results are as follows: 1. Remove the remains of diseased plants in the field. The diseased female and male plants of seed production corn were pulled out in time when the male and female were selected. After corn harvest, the diseased plants were completely removed and burned or buried deeply in combination with deep ploughing of the soil.

2. Rotation. Rotation of corn and other non-host crops was carried out to prevent the accumulation of soil pathogens. The seriously affected plots can be rotated with rice, potato and vegetable crops for 2-3 years.

3. Rational fertilization. The combination of potassium fertilizer or phosphorus and nitrogen fertilizer was applied to maize at jointing stage or booting stage. Potassium deficiency plots, generally apply 7.5kg potassium chloride per mu, or 25kg per mu of ternary compound fertilizer. Among the cultivation factors, the rational application of nitrogen, phosphorus and potassium can enhance plant growth and improve disease resistance, especially potassium chloride can reduce the occurrence of stem rot.

4. Reasonable close planting. Keeping ventilation and light in the field and good soil permeability can reduce or delay the disease. When stem rot occurs, remove 2-3 leaves at the lowest part of the stem, remove diseased plants and old leaves, and burn them centrally.

5. Strengthen the cultivation and management. Open the drainage ditch, lower the groundwater level, timely drainage in the rainy season, so that there is no stagnant water in the rain; cultivate the soil by stages and loosen the soil in time to avoid all kinds of damage.

6. Get rid of insects in time. Control aphids, gray planthoppers, corn borer and underground pests, put an end to the transmission of virus and bacteria, and prevent germs from entering the insect-infested wounds and harming plants.

7. Stem base disease can remove the soil around the base of the stem in time, reduce humidity, reduce infection, and wait until after the peak period of the disease. And pull out the seriously diseased plants in time, burn them or bury them deeply to avoid spread.

8. Chemical control. At the initial stage of the disease, spray control with 50% carbendazim wettable powder, or 65% mancozeb wettable powder, or 70% chlorothalonil wettable powder, or 20% triadimefon EC 3000 times, or 50% carbendazim 1500 times. The root was irrigated with 98% carbendazim 2000-3000 times in the middle stage of the disease.