Effects of 3 Different Soil Fumigation on Control of Soil-borneDiseases and Agronomic Traits of Flue-cured Tobacco

Combine the plant species and planting pattern in Kunming tobacco field in spring, 3 soil fumigation of chemical, biological and combined chemical and biological fumigation techniques were carried out, and the effects on the prevention and control of soil-borne diseases and yield of flue-cured tobacco were studied. The findings revealed that the killing rates of 4 representative pathogens of soil-borne diseases by 375 kg/ hm² dazomet treatment, biological mustard fumigation treatment, 150 kg/ hm² dazomet combined with mustard were, respectively, 97.51%, 45.09%, 80.27% for phytophthora, 97.56%, 48.63%, 72.14% for pythium, 95.51%, 55%, 72.14% for fusarium, 93.99%, 65%, 83.18% for root knot nematode; the prevention and control rates of 4 soil-borne tobacco diseases were, respectively, 88.10%, 66.93%, 78.44% for black shank, 91.05%, 71.90%, 85.03% for black root rot, 91.05%, 64.78%, 74.42% for root knot nematode disease, 61.30%, 43%, 57.33% for bacterial wilt; the stem diameter, leaf number, leaf length and leaf width of the three fumigation treatments increased positively, and the yield of flue-cured tobacco was 1.79 times, 1.26 times and 1.52 times that of the control , respectively. Three fumigation treatments had a certain effect on the prevention and control of soil-borne diseases and yield increase of flue-cured tobacco, and effect of dazomet were the most significant, and the effect of combined was between dazomet treatment and mustard treatment. Dazomet and mustard fumigation is a new and effective pesticide reduction technology. In production, different fumigation and disinfection methods can be adopted according to the number of phytophthora, rot, fusarium and root-knot nematode in different tobacco planting soil.