Prevention and Control of Cotton Diseases should start at Seedling stage

The main diseases in cotton seedling stage are blight, anthracnose, black spot, quenching, root rot and so on. The main cause of cotton seedling disease is seed and soil bacteria. Once the suitable climatic and environmental conditions are encountered, cotton seedling disease will occur seriously, endangering the normal growth of cotton seedlings. In general, the incidence of seedling disease is 30% to 50%. In recent years, with the popularization of transgenic insect-resistant cotton, the seedling disease of cotton is gradually aggravated, which directly threatens the early development of whole and strong seedlings of cotton. Therefore, the comprehensive control of cotton seedling diseases has become a safeguard measure that can not be ignored to increase cotton production.

First, the seeds are strictly disinfected. Strongly advocate the purchase and selection of high-quality coated seeds, put an end to seed carrying bacteria, and improve the effect of disease prevention and pest control. For all cotton fields that do not use coated seeds, the cotton seeds used must also be mixed, suffocated or soaked with high-efficiency fungicides to do a good job in seed disinfection to prevent seed infection.

Second, sow seeds at the right time. The transgenic disease-resistant varieties had poor tolerance to low temperature, slow emergence, weak seedling potential, early sowing, long emergence time, high nutrient consumption, more chance of infection and serious disease. Therefore, sowing should not be too early or too late, and the principle of timely sowing must be grasped. In general cotton fields, it is suitable to sow seeds when the soil temperature of 4 cm is stable at 14 ℃, and when the soil temperature of 5 cm is stable at 15 ℃-16 ℃.

Third, strengthen the field management of cotton at seedling stage. When the weather is dry, the cotton fields with poor soil moisture should seal the seedling holes in time with the release of seedlings in order to preserve the soil moisture; when the soil moisture under the film is high, and in case of overcast and rainy days, the time of sealing the seedling holes can be postponed appropriately, and when the soil under the film is loose and the soil temperature is suitable, the seedling holes should be sealed again to facilitate the release of soil moisture and reduce the disease; in open field cotton fields, soil heat preservation should be timely loosened, soil moisture should be preserved in case of drought, soil moisture should be dispersed in case of waterlogging, and near seedlings should be loosened. At the same time, we should also know how to fix the seedlings in time, and when the seedlings grow 1 or 2 true leaves, it is beneficial to the individual development of cotton seedlings and enhance the ability of disease resistance.

Fourth, chemical control, nutritious and strong seedlings. After the seedlings were fixed, the cotton seedlings were sprayed with fungicides and high efficiency foliar fertilizer to prevent disease and strengthen the seedlings. At the beginning of cotton seedling disease, you can spray "carbendazim" or carbendazim or methyl topiramate, add 0.2% potassium dihydrogen phosphate or get pure rare earth nutrients. During the peak period of the disease, 2500 times of malevolent Ling and 3500 times of Tianfengsu can be sprayed. Cotton seedlings with serious disease can be irrigated with 1000 times of "bacteria" alone. Cotton seedling stage, generally 7-10 days to control once, continuous control for 2-3 times, can not only reduce the harm, reduce the loss, but also basically ensure the normal growth of cotton seedlings.