Cotton bacterial horn spots often occur, what are the symptoms of cotton bacterial horn spots?

At the seedling stage, the cotyledons are diseased, appearing dark green dots, then turning into oily dots, and finally expanding into round or irregular dark brown dots, and the severe cotyledons die and fall off. When the damage is mild, it will affect the normal growth of seedlings. When the damage is severe, the cotyledons dry up and the seedlings die.

The pathogen can spread from the cotyledonous petiole to the young stem, first as oily spots, then black and brown, and the lesions gradually expand around the stem. After that, the lesions partially rot, shrink, and thin, and the cotton plant bends to one side. At the adult stage, dark green spots appear on the back of the diseased leaves, and then rapidly expand into oily spots.

At this time, the lesion also appears at the tip of the leaf, and because the expansion of the lesion is limited by the surrounding veins, it becomes a polygon. Remove the remains of diseased plants in cotton fields in time, and compost or incinerate them in a centralized manner.

Cotton seeds should be carefully selected, planted reasonably densely, drained in time after rain to prevent water retention, and diseased plants should be pulled out in time in combination with seedlings and seedlings. Adopt formula fertilization technology to promote the use of compost made from fermentation bacteria to avoid partial excessive application of nitrogen fertilizer. Promote the use of ridge cropping or high furrowing, and strictly prohibit scientific irrigation, flood irrigation and continuous irrigation.

Timely tillage and release of soil moisture. Hair removal with concentrated sulfuric acid can eliminate the carrier of cottonseed. For specific methods, see Cotton Verticillium wilt.

Seeds with pathogens are prone to rotten seeds and sprouts after sowing. Small round spots of water stains appear at the beginning of each part and then expand into irregular or polygonal spots. The spots on the leaves are translucent to light, and they expand along the veins to form dark brown bands.

In hot and hot weather, the affected area often secretes dewdrop mucus, which is the pus of the pathogenic bacteria. Disease-carrying cottonseed is the main source of infection, followed by disease residues and pathogens left in the soil. Bacterial pus produced in the affected area is reinfected by wind, rain, and insects, and invades through the stomata.

The occurrence of this disease is closely related to temperature and humidity. There are many wounds caused by storms and pests, which are conducive to the spread and infection of germs, which can easily lead to the epidemic of diseases.

Spray other Bordeaux liquid at the seedling stage, 50 to 70 kg of liquid medicine per mu. Drain the stagnant water in time after the rain, disperse the soil moisture through tillage, and be careful not to flood the watering in case of drought. At the same time, pay attention to the rational allocation of fertilization, and do not overuse nitrogen fertilizers such as urea.

Remove fallen leaves and pruning leaves in cotton fields in a timely manner, and destroy them in a centralized manner or bury them deeply. For diseased land, 72% of agricultural streptomycin (commonly known as streptomycin in English) can be used in 1500 2000 times the solution.

Choose to add 50% carbendazim) 500 times solution, 70% melamine-methyl) 800 times solution, 25% copper sulfate 500 times solution, regenerant (copper complex, zinc complex, lemon copper mixture). In order to promote the healthy growth of plants, nutrient regulators (yield enhancers) such as aquamarine, strong liquid fertilizer, chlorhexidine, brassin, diammonium aqueous solution can be added at the same time, and sprayed once every 5 days or so, spraying 2 3 times in a row.

Cotton can be diseased throughout the growth period, and the pathogen can harm seed buds, cotyledons, true leaves, stems, bud bells, bracts and other parts, and seeds with bacteria are prone to rot seeds and buds after sowing. The small round spots of water stains appear at the beginning of the damage of each part, and then expand into irregular or polygonal lesions, and the lesions on the leaves are translucent to light, and there are extensions along the leaf veins, forming black-brown long strip-like lesions. In high temperature and high temperature weather, the diseased part often secretes dewdrop-like mucus, which is the bacterial pus of pathogenic bacteria.

Cotton can occur throughout the growth period. Cotton seedlings are diseased before they are unearthed, causing rotten seeds and buds, and they cannot emerge. At the seedling stage, the cotyledons are diseased, with small dark green dots, which then turn into oily spots, and finally expand into round or irregular black-brown lesions, and severe cotyledons die and fall off.

When the damage is light, it affects the normal growth of seedlings, and when the damage is heavy, the cotyledons dry up and fall off, and the seedlings die. The fungus can spread from the cotyledonous petiole to the young stem, initially as oily spots, then turn black-brown, and gradually expand the lesions around the stem. After the lesion partially rots, shrinks and becomes tapered, and the cotton plant bends to one side.

Flower wilting can occur because the disease of this plant is very severe and can affect the growth of the plant.

There will be some black spots, and then the quality of the cotton is not very good, and the leaves will also show some wilted appearance. When planting cotton, it is necessary to spray pesticides on the soil of cotton, and then spray pesticides on time according to the growth cycle of cotton.

It is found that there are some dark brown spots, and there will also be leaves falling off, and it will be extended, the wilting situation is more serious, and it will also seriously lead to root rot, and there will be some pus.

The yield will be reduced, and the roots will turn black and the leaves will wilt and fall. Spray pesticides in a timely manner, and you should choose some good seeds, and be sure to strengthen ventilation management.

Because cotton horn spot is different from other diseases of cotton, cotton horn spot is a bacterial disease that can damage cotton throughout the growth cycle, but it occurs seriously in cotton seedlings. Especially in the case of high field temperature and high air humidity, cotton horn spot disease occurs in a large area, causing cotton leaf ulceration and boll dropping, resulting in a serious decline in cotton yield. If the cotton horn leaf spot disease is not prevented and controlled in time at the beginning of the disease, the pathogen will continue to multiply and spread through air flow and rainwater, resulting in rapid infection of cotton, and the death of the whole cotton in severe cases, which is the most headache for farmers.

After being infected with cotton horn spot at the seedling stage, after 1-2 days of incubation, the pathogen will produce waterlogged small spots on the front of cotyledons, which are round in shape and light green in color. Later, as the humidity in the field increases, the previously small spots will expand into large round or irregular spots, and the color will change to gray-brown. In severe cases, the lesion will secrete smelly yellow pus, and the leaves will fall off. After the occurrence of cotton horn leaf spot, if the true leaf is infected, small round spots will appear on the back of the leaf at first, and the color will be dark green; After that, the lesions will gradually enlarge, and due to the restriction of the veins, polygonal lesions with brown water stains will form.

This damages the leaves and infects the green cotton peaches and stems. After the cotyledons benefit, waterlogging black spots appeared on the diseased parts, and they turned black and brown in the early stage. When the true leaf is sick, dark green spots first appear on the reverse side of the leaf, and then waterlogging spreads. Due to the limitation of venous tissue, the lesions are polygonal.

Sometimes the lesions grow along the veins and turn into dark brown bands of ignorance. Qingling benefited, at first there appeared dark green needle spots, later expanded into water-stained round lesions, the early stage became reddish-brown, shortened sedimentation, into dark brown rotten spots, that is, the initial scattered.

Pathogens overwinter on seeds and diseased residues and will be a source of infection for the following year's disease. The level of cottonseed carrier is a decisive indicator of disease severity at seedling stage. Temperature and humidity are closely related to the onset of the disease, and moderate temperature and rainy weather are the main prerequisites for the onset of the disease.

When the soil temperature is 10-15, the disease generally does not occur, the disease begins at 16-20, and the disease is most severe at 24-28. When the temperature exceeds 30, the disease worsens, and when the humidity is above 85%, the disease grows the fastest. The more thunderstorms there are from early June to early August, the more severe the condition.

Choose disease-resistant varieties. Drying the seeds for 2-4 days can significantly reduce the carrier rate of horn spot. Seed disposal penalties.

Prevention and control methods: cleaning, strengthening cultivation management, cotton seed disinfection, seed selection, spraying. Diseased cotton with bacterial horn spots was found, the diseased residue was removed, and it was burned and buried deeply.

Soak the seeds in hot water at 55 60 for 30 minutes, soak the ashes of Dixon grass and wood in warm soup, and sow with mixing. Morning seedlings, late seedlings, reasonable fertilization, early seedling stage, diligent cultivation.

1. Fine land preparation, application of foot fertilizer, irrigation of bottom moisture, selection of disease-resistant varieties. 2. Reasonable crop rotation, deep winter irrigation, and promote the decomposition of sick and residual bodies. 3. Strengthen tillage at the seedling stage, reduce soil moisture, apply less nitrogen fertilizer, increase phosphorus and potassium fertilizer, and cultivate strong seedlings.

4. Strengthen the management of cotton fields, drain water in time after rain, and remove the remains of diseased plants in time to take them out of the field for deep burial or burning, so as to reduce pathogens in the field. 5. Before sowing, the cottonseed is depiled, and the depilation with sulfuric acid can effectively kill the horn spot fungus carried on the cotton seed linters, and at the same time, it can also kill other germs spread by the seed.

At the seedling stage, tillage should be strengthened, soil moisture should be reduced, nitrogen fertilizer should be applied less, and phosphorus and potassium fertilizer should be increased. Strengthen the management of cotton fields, prune and prune in a timely manner, and remove old leaves. Remove stump branches, dead leaves, rotten clocks, etc. Buried in the ground or incinerated intensively. Do not leave sick and dead bodies in the wild.

The aboveground part of cotton is damaged throughout the growing period. Damaged leaves, stems, and bells. They all produce dark green oil stains (or water stains).

Later, the spots turn black-brown and the spots on the leaves are translucent. The morphology of the spots varies depending on the site of infestation: the spots on the cotyledons are mostly round or indeterminate; The lesions on the true leaf are polygonal due to the restriction of the veins, and sometimes they are jagged along the veins. The bract lesions are similar to true leaves; The lesion on the boll is round and slightly concave, which can extend into the inside of the cotton boll, making the fibers yellow and suppurative; Lesions on stems and shoots can easily break around the stem.

In humid conditions, the affected area often secretes a yellow mucus slurry. After drying, a light gray film is formed.

<> Cotton bacterial keratoses are a bacterial disease caused by infection with the bacterium Xanthomonas malva (Canola xanthomonas malva). Bacterial keratosis in cotton, which can occur throughout the growing season of cotton. Bacteria can damage the buds, cotyledons, true leaves, stems, reindeer, and bracts of the species.

Lesions at different sites appear as small round water spots and then irregular or polygonal spots. The spots on the leaves are translucent under the light orange and extend along the veins, forming long bands of dark brown spots. In hot weather, the lesion often produces dew-like mucus, which is a pathogenic bacterial sepsis.

Cottonseed was the main source of infection, followed by residues and soil residues. The disease department produces bacterial pus through wind and round rain, and insects spread to cause reinfection and stomatal invasion. The occurrence of this disease is closely related to temperature and humidity.

Thunderstorms and pests and diseases cause a lot of damage, promote the spread and infection of bacteria, and easily cause epidemics of diseases. Clean up the cotton fields, remove the sick and disabled cotton fields, burn them intensively, and bury them deeply.

Strengthen the cultivation management of early sowing, late sowing and reasonable fertilization. At the seedling stage, we have to plow early and frequently. There were obvious differences in disease resistance among cotton varieties.

Cotton seeds are sterilized and peeled with sulfuric acid, soaked in 55 60 hot water for 30 minutes, and removed to dry. It is then mixed with 10% weight of pine residue seeds (250 g pine residue plus kg of pine residue) and sown with the mixture. Or mix the seeds with 20% dicofol wet powder to the weight of the seeds.

Spray the equivalent Bordeaux solution at the sowing stage, spraying 50 70kg per acre.

Choose disease-free varieties to make the front seeds, or carry out the seed management, the "three open and one cool" warm water (55 60) that is used is effective for soaking the seeds Use disease-resistant varieties Strengthen field management, especially after typhoons and heavy rains, topdressing fertilizer is an important measure to control the development of diseases Pesticide control: spraying with 120 200 times the Bordeaux liquid is effective, and agricultural chloramphenicol can also be sprayed in severely ill areas.