How do we control cotton seedling red rot in cotton?

Pesticides. Because pesticides can prevent and prevent red rot well, pesticides should be used to prevent and control them.

To use professional pesticides and fertilizers, choose different agents according to different conditions, choose different effects, and pay attention to the time of application.

When selecting seeds, choose some good seeds, clean and take care of the weeds and dead leaves on the cultivated land in a timely manner, and strengthen the management of cotton.

It is necessary to improve the fertility of the soil, to increase the pH value of the soil, to do a good job in prevention, to apply fertilizer in time, and to use pesticides and fertilizers in time.

Prevention and control methods: At the early stage of the disease at the seedling stage and boll stage, spray the following agents in time:

65% zeb wettable powder 500-800 times liquid + 50% thiophanate-methyl wettable powder 800 times liquid;

80% mancozeb wettable powder 700 800 times liquid + 50% carbendazim wettable powder 800-1 000 times liquid;

50% diphtholexin wettable powder l 500 times, spray 100 n125kg per mu, once every 7 10 days, spray 2 3 times continuously, and the control effect is better.

FYI.

Infection at the seedling stage, damage before the young shoots emerge can cause rot buds. The infected ducts of young stems turn dark brown, and yellow streaks appear at the base of young stems near the ground, which then turn brown and rot. The young stem is sick, yellow spots appear at the base of the stem, and then turn brown and rot, the duct becomes dark brown, and the young stem and young roots below the soil surface are swollen.

Gray-red irregular spots are produced on the edges of cotyledons and true leaves, and when the humidity is high, the whole leaves become brown and wet rot, and pink mold layer is produced on the surface. After the cotton boll is infected, the initial amorphous lesions are dark green, water-stained, and the disease expands rapidly in humid weather or even rain, covering the whole boll, producing pink or light red mold layer, the diseased boll can not crack normally, and the cotton fiber rots into a stiff petal. After the onset of seeds, the germination rate decreases.

Occasionally, the base of the adult stem is affected, producing ring-shaped or local brown lesions, the skin is rotten, and the xylem is yellow-brown.

Seed treatment is an effective measure to prevent red rot at seedling stage, and spraying control at the seedling stage and boll stage can effectively control the occurrence of the disease.

40% seed dressing double wettable powder 200g 100kg seeds can be used.

At the seedling stage, the early stage of the disease of the boll stage, and the following agents are sprayed when burning silver

65% zeb wettable powder 500-800 times liquid + 50% thiophanate-methyl wettable powder 800 times liquid;

Thanks for the reference.

Cotton red rot is a harmful seedling disease in cotton planting in China, which mainly causes cotton seed rot, bud rot, stem base rot and root rot.

Red rot of cotton seedlings mainly occurs in the embryonic stem and roots, and cotyledons and true leaves can also be damaged.

Hazard characteristics: Cotton seedlings are damaged before they are unearthed, and the young shoots turn brown and rot. The young stems and roots are damaged, the root tips and lateral roots turn yellow first, and then the whole root turns brown and rot, and the young stems and young roots under the soil are hypertrophied.

Cotyledons mostly develop from the margins, with small yellow-brown spots at first, and then expand into irregular or nearly round gray-red lesions. When wet, a pink mold layer appears on the surface of the lesion; At low temperatures, the lesions stop developing and turn brown, with darker, brittle edges. The symptoms of true leaves are similar to those of cotyledons, and the top young true leaves and growth points are damaged and rot in a black-brown color.

The optimal temperature for the onset of the disease is 19 24, the relative humidity is above 80%, the sunshine is less, the rainfall is more, and it is easy to be epidemic. When there were more than 10 lateral roots from cotyledons to cotyledons, the roots were the most damaged. When the seedlings are 2 weeks old, the cotyledons are the most seriously damaged, and they are often all dried up; After the true leaves, the disease resistance is enhanced, and it rarely causes the death of seedlings. The disease is severe in saline and alkaline soils, and the disease is mild in sandy loam soils.

The disease is severe in low-lying cotton fields and mild in high-lying slopes. The disease was severe in continuous cropping cotton fields and cotton fields with leguminous crops, and the disease was mild in cereal crops. Early sowing is severe.

1.Cotton seedling blight is the main disease at the seedling stage in the northern cotton area. Fuyan is caused by rhizoctonia infestation in the soil.

Generally, the mortality rate of seedlings is 5% to 10%, and the incidence of spring rain or cold snap is serious, which can reach more than 50%, resulting in lack of seedlings and broken ridges, and has to be destroyed and replanted.

2.Red rot in cotton seedlings is a root rot disease caused by Fusarium infestation in the soil. In the north of the Liaohe River Basin and the Yellow River Basin, there are many missing worlds, and the Yangtze River Basin is light and heavy.

The pathogen overwinters with diseased residues or saprophytes in the soil, and the conidia and mycelium produced in the following year become the primary source of infection. At the beginning of the seedling stage, the source of infection can also be attachment.

The conidia and mycelium lurking inside the seeds on the seed linters invade the buds or seedlings after sowing. The fungus is saprophytic during the cotton growing season. At the cotton boll stage, conidia or mycelium are transmitted to the cotton boll by wind, rain, insects and other media, and invade from the wound to cause rotten boll rot, and the diseased boll causes bacteria to carry bacteria inside and outside the seed, forming a new infection cycle.

The growth activity of red rot bacteria in the temperature range of 3 37 is optimal20 24. High temperatures are beneficial for infestation. The incubation period is 3 to 10 days, the length of which varies depending on environmental conditions.

Less sunshine, heavy rainfall, and more rainy days can cause a pandemic. The disease is more severe at low temperature and high humidity at the seedling stage. The boll period is also prone to rainy temperatures, low temperatures, and high humidity.

Cotton plants are greedy for green and long, or cotton bolls are damaged by diseases and insects, and there are many mechanical wounds, and the germs are easy to invade and become seriously ill. During the cracking period of cotton bolls, the climate is dry and the onset is mild.

Thanks for the review.