Verticillium wilt is an important disease in cotton production. Since 2007, the disease has been increasing in Jianhu County year by year. In 2009, the incidence of the disease in the whole county was nearly 35,000 mu, accounting for 91.4% of the total area of ​​cotton, and it has become a local constraint. Important factors for high yield and stable production of cotton. Cause of the outbreak 1. The poor resistance of varieties is the main reason for the outbreak of Verticillium wilt in cotton. The selection of disease-resistant varieties is an effective means to prevent fusarium wilt and Verticillium wilt. However, due to the little progress in the breeding of Verticillium wilt resistance, the cotton varieties currently used in Jianhu County are mostly resistant to Fusarium wilt, but have poor resistance to Verticillium wilt, and even have high jaundice. 2. Continuous cropping is an important new cause of Verticillium wilt in cotton. In Jianhu County, although the cotton planting area has been declining year by year, the eastern townships still plant cotton and other dry crops due to topography, soil quality, and people's growing habits. Surveys in recent years have found that the Verticillium wilt disease in continuous cropping areas is heavy and accompanied by serious dead seedlings. 3. The climate factor is the cause of the verticillium wilt outbreak in cotton. The occurrence of verticillium wilt in cotton is closely related to temperature and humidity. During the growing period of cotton, temperature can occur at 20-28°C Verticillium wilt, and the optimum temperature is 25-28°C. Raining more cotton buds, the temperature is conducive to disease. From late July to mid-August 2009, during the bud stage of cotton, Jianhu County experienced continuous low temperature, rain, and sunshine, and the daily average temperature remained at around 25°C, which is very suitable for occurrence of Verticillium wilt in cotton. In addition, cotton is not tolerant to flooding, and the accumulation of water in the field affects the growth of its roots, and is more susceptible to damage caused by yellow wilt. Prevention 1. Select disease resistant varieties. Establish a disease-free seed breeding base and implement quarantine at the place of origin. Selection of resistant varieties such as Zhongmiansuo 45, SGK321, Lumianyan No. 18, etc. 2. Rotation change. This is the most effective measure to control Verticillium wilt. Gramineous wheat, barley, corn, rice, etc. are not harmed by Verticillium dahliae, and diseased fields can turn cotton and these crops. The practice of paddy-upland rotation in recent years has proved that a 2-3-year rotation with rice can greatly reduce the amount of field bacteria and effectively reduce the incidence of Verticillium wilt. 3. Turn the soil deep. The Verticillium dahliae in cotton are mainly distributed in the 0-20 cm tillage layer. Deep-turning can reduce the amount of bacteria in the tillage layer and reduce the rate of diseased plants. 4. Remove the sick and use a disease-free net fertilizer. Timely removal of the fallen leaves in the cotton field was concentrated on the ground or outside the field. Cottonseed cakes and cotton seed hulls can also carry a large number of germs and cannot be directly applied as fertilizer to cotton fields. Nitrogen fertilizers have the effect of inhibiting the growth of Verticillium dahliae. Potash fertilizers help reduce disease. 5. Irrigation and drainage facilities, delayed sowing, short-term film removal. Smooth the cotton fields, improve the drainage system, change the flood irrigation into small-flow furrow irrigation, and drain water in time after the rain. Insect-resistant cotton is mostly medium-early-maturing varieties and the sowing date should not be too early. Seeds were planted at early stage with low budding and budding blossomed early; planting soon after sowing was quicker, seedling was stronger, and disease resistance was stronger. The mulch cotton should be uncovered at Shenglei to early flowering period to improve the resistance and disease resistance of cotton. At the same time, through cultivating soil, the drought can be poured and the fish can be discharged. 6. Chemical control. Seeds and soil are disinfected during sowing. At the beginning of the disease, timely use 3%?f moldy cream water agent 30-40 ml water 50-60 kg to irrigate root, or use 3%?f moldy nail cream agent 300-500 times liquid spray, 10 days once, continuous control 3 -4 times. Pvc Portable Resuscitator,Pvc Transparent Respirator ,Simple Respirator,Emergency Resuscitator Jiangsu Yongle Medical Technology Co., Ltd. , https://www.jsylmedical.com
Comprehensive measures against the outbreak of Verticillium wilt in cotton