1. Protection from disease areas
At present, the disease-free area in China is still large, and it is necessary to control the cotton varieties without disease-free areas to lead to scale. When introduction is really necessary, it should be disinfected (the seeds are depilated with sulfuric acid, then soaked with 80%402 antibacterial agent at 55 ~ 60℃ for 0.5h, or soaked with 0.3% carbendazim gel suspension at room temperature 14h), and after 2 ~ 3 years of trial planting, identification and propagation, it will be popularized in a large area. At the same time, it is necessary to prevent more pathogenic strains from being introduced into new areas. To establish a disease-free Taneda, choose cotton seeds without diseases.
2. Planting disease-resistant varieties
Planting disease-resistant varieties is the most economical and effective measure to control cotton wilt. In 1960s, China cultivated 65,438+03 disease-resistant varieties represented by Shaanxi 4065,438+0. By 65,438+0977, the extension area reached 654.38+0.67 million hm2, which reduced the harm of Fusarium wilt in the hardest hit areas. In 1970s, 29 disease-resistant varieties represented by 86- 1 were bred. By 1986, the planting area in China is about1100,000 hm2, and the harm of cotton wilt in the hardest hit areas has been initially controlled. In the 1980s, 48 varieties with resistance to yellowing, represented by China Cotton Institute 12, were bred, reaching 1990, and the national popularization area was1.20,000 hm2, which basically controlled the wilt of cotton areas in the north and south of China. After 1990s, the varieties bred in the northern and southern cotton regions of China are basically resistant to Fusarium wilt, such as China Cotton Institute 24, 27, 35 and 36, Yumian 19, Baimian No.2 and so on. Xinjiang also bred Xinluzao 9 and 10, which played an important role in controlling the occurrence of Fusarium wilt. When breeding and popularizing disease-resistant varieties, we should pay attention to the following points: disease-resistant varieties are not completely sterile, and some varieties have no obvious external symptoms during their growth period, but stem cutting, morbidity and disease index are high. The effect of this kind of diseased plants on yield needs to be investigated, but the seed carrying bacteria can not be ignored. At present, it is found in Xinjiang cotton area that planting some disease-resistant varieties in disease-free areas or light areas and then planting local susceptible varieties often leads to obvious aggravation of disease and even death in pieces. Disease-resistant varieties should take measures to continuously purify and rejuvenate, and at the same time, combine excellent cultivation measures, that is, good varieties and good methods, and give full play to disease-resistant ability. At present, many disease-resistant varieties have lost their disease resistance in just a few years after being introduced into the new area. The reason is not only related to the large number and strong pathogenicity of local pathogens, but also related to the stability and mechanical hybridization of varieties. Pay close attention to the distribution, fluctuation and variation of physiological races, and provide basis for disease-resistant breeding in time.
3. Crop rotation
Rotation of maize, wheat, barley, sorghum, rape and cotton in seriously ill fields for 3-4 years has obvious effect of relieving diseases, and rotation of rice and cotton or alfalfa, cotton and planting green manure has better effect.
4. Strengthen cultivation management
Applying base fertilizer, phosphorus and potassium fertilizer, sowing in time, reasonable close planting, fixing seedlings in time, pulling out diseased seedlings and spraying reliable pesticides on 2 ~ 3 cotton seedlings with real leaves are beneficial to the growth and development of cotton seedlings and can improve disease resistance. When planting seedlings and pruning in diseased fields, clear the diseased plants in time, bury them deep outside the fields, and apply hot-pressed cotton cakes and sterile soil miscellaneous fertilizers, which can reduce the incidence rate. In cotton seedling transplanting area, using reliable methotrexate or powder as seedbed soil disinfection can obviously reduce the harm of Fusarium wilt. At the initial stage of the disease, the root irrigation with credible oridonin or powder, credible mycophenolate mofetil or credible oridonin can achieve obvious results.