What are the common diseases of cotton?

What are the common diseases of cotton? What are the hazards? Please also know the netizens to help introduce the common diseases of planting cotton, such as standing blight, Fusarium wilt, black rot, virus disease and stem blight; the planting network has sorted out the harm and control methods of the above cotton diseases, which are listed below for netizens' reference. The harm of cotton blight: cotton blight is commonly known as root rot and black root disease, which occurs in all cotton areas throughout the country. after the damage of cotton seedlings, yellow-brown disease spots are produced at the base of the stem near the ground, and then become dark brown, and gradually sunken and rot, and in serious cases, the disease becomes thinner, and the diseased seedlings die or wilt. After the cotyledons were damaged, irregular yellowish-brown spots were formed, and then the disease part was broken and fell off into a perforated shape. After the damage in the adult stage, brown spots appeared on the leaves, and then shedding and perforation. The control methods of blight disease are as follows: 1. Rational rotation: with Gramineae crops: rotation for more than 2-3 years. 2. Rational fertilization: fine soil preparation, increasing the application of rotten organic fertilizer or 5406 bacterial fertilizer. 3. To improve the sowing quality: the suitable sowing time for spring cotton is 5 cm deep and 14 ℃, and the general sowing time is 4 cm deep and 5 cm deep. 4. Strengthen the management of seedling stage: properly early seedling and diligent ploughing, reduce soil moisture, increase upper temperature and cultivate strong seedlings. 5. Dressing selected seeds with medicament. Mix seeds with 50% carbendazim of 0.5% to 0.8% seed weight, or 50% methyl topiramate of 0.6% seed weight. The harm of cotton Fusarium wilt: Fusarium wilt, also known as plant cancer, is the archenemy of cotton production, which has spread rapidly in recent years. Fusarium wilt is characterized by dwarf plant, gray-green leaves, brittle and hard stem, bent stem, shortened stem knot, sunken center, and grayish brown or light black vascular bundles in the stem. Disease conditions: high temperature and humidity, continuous stubble planting, sunny day after rain, will be a line, into pieces of death. The control methods of Fusarium wilt are as follows: 1. soil improvement: on the basis of applying organic fertilizer, nitrogen, phosphorus and potassium, 0.5 kg heavy stubble is applied per mu, and then ploughing, which can kill most of the bacteria in the soil and increase the air permeability in the soil. eliminate the content of sulfite in the soil, break the consolidation, and improve the saline-alkali. Enhance plant disease resistance and reduce the harm of Verticillium wilt. 2. timely watering, cotton has an average of two bolls per plant, watering the first water in dry weather, early watering will promote the occurrence of the disease; 3, spraying 24 times of first aid at seedling stage, bud stage and flower and boll stage, or carbendazim to control Verticillium wilt. 4. The diseased plants can be prevented and treated surgically. The vertical mouth of 2 cm and 3 cm is cut with a knife at 5 cm to 6 cm on the base of cotton, and two sections of matchsticks soaked in withered yellow first aid solution for more than 4 hours are inserted. The above methods can not only effectively control the harm of cotton Fusarium wilt, but also control the Fusarium wilt of other crops. The harm of cotton black rot: black rot cotton root epidermis is black, slightly protruding, no new roots grow, the plant is short, the leaves are soft, the growth is slow, it is easy to die under high temperature, the plant is black withered after death, upright, and the disease area is massive. The land with long stagnant water after rain, low-lying terrain, heavy saline-alkali or large amount of nitrogen fertilizer was not ploughed in time, and sweet potato, sugar beet, Chinese cabbage, cabbage and radish planted in the previous crop were prone to this disease. Black rot prevention and control methods: 1, leveling the land, prevent stagnant water, timely drainage. 2. Ploughing and loosening the soil in time after rain to improve the root activity. 3. The incidence of the disease can be reduced and controlled by adding 15 kg of lime powder per mu, 10 kg of ferrous sulfate or heavy stubble. 4. Increase the application of organic fertilizer and phosphorus and potassium fertilizer, control and apply appropriate amount of nitrogen fertilizer; 5, use withered yellow first aid during the disease period, 20 grams of rotten Sukang, adding 15 kg of water, spraying foliar or root irrigation can effectively control black rot. The harm of cotton virus disease: cotton virus disease mainly includes lobular virus disease, mosaic virus disease, curl wilt disease, purple leaf virus disease, deciduous leaf disease, falling flower and fruit drop virus disease, which is called plant AIDS and spreads quickly. serious harm, reduced production in the invisible, is the first enemy of plants. The methods of prevention and control of virus disease: in the early stage of cotton growth, it can be prevented by virus doctor, antitoxin, virus killing and withering. The harm of cotton stem blight: cotton can be damaged from seedling stage to boll setting stage, and the early stage is harmful to cotyledons, true leaves, stems and growing points, resulting in rotten seeds, leaf spots, stem withering, decaying leaves and even the whole plant to die, and infecting bracts and green bolls in the later stage. causing deciduous leaves and stiff petals. Cotyledons and real leaves are yellow-brown small round spots at the beginning, the edges are purplish red, and then expand into nearly round or irregular brown spots, with many small black spots (pathogens) scattered on the surface. The stem and petiole were damaged, initially as reddish-brown dots, and then expanded into dark brown fusiform ulcer spots, sunken in the center, and purplish red around. When the disease is serious, the disease part breaks and falls off, and the stems and branches die. The control methods of stem blight are as follows: 1. Reasonable crop rotation, reasonable close planting and improving ventilation and light transmission conditions. 2. Seed dressing, sulfuric acid depilation of cottonseed, mixed with seed coating agent with the ratio of carbofuran and carbendazim 1. 5, can prevent disease and control aphids at the same time. 3, spray, seedling stage or adult stage disease, can be used 65% Dysen zinc 800x solution, or 70% methyl topiramate 1000 times solution spray treatment. How to prepare for cotton before sowing? click to get more cotton planting technology click to get more food crop planting technology