Study On The Occurrence Trends And Green Prevention And Control Techniques Of The Main Diseases Of Tobacco In Qian Jiang

Flue-cured tobacco,also known as fire-tube flue-cured tobacco,is the main raw material of the cigarette industry.China's flue-cured tobacco production is mainly concentrated in Yunnan,Henan,Guizhou,Shandong and other provinces.China flue-cured tobacco was introduced from South America in the late Ming and Qing dynasties.The main planted varieties have experienced introduction from outside to self-cultivation and promotion.The tobacco industry has gone from stagnation to gradual finalization.Now flue-cured tobacco has become an important economic crop in China and one of the bulk agricultural products exported by China.The yield and quality of tobacco are restricted by various factors such as variety,soil environment,climate factors,planting methods,and pest management.According to statistics,there are more than 600 harmful microorganisms that have caused the decline in tobacco production and the quality of tobacco leaves.Among them,there are more than 70 kinds of harmful microorganisms,including tobacco mosaic disease,black shank,bacterial wilt,root black rot,Ring spot virus,tobacco worm,cutworm,etc.The results showed that the prevalence of black shank was mainly caused by rainfall;the combined effect of high temperature and heavy rainfall led to the sudden epidemic of bacterial wilt;high temperature and low rainfall were the main inducers of tobacco mosaic virus.Qianjiang District of Chongqing City is located in the interior of Wuling Mountain and belongs to the tobacco planting area in southeast Chongqing.Qianjiang has a history of growing tobacco for more than 60 years and has the potential to produce high-quality tobacco.However,Qianjiang tobacco area often has low temperature in the early period of tobacco growth,high temperature and high humidity in the later period.The weather,coupled with the fact that tobacco fields are mostly located in high-altitude areas,special geographical and climatic conditions have caused it to become a high-incidence area for four diseases such as tobacco bacterial wilt,black shank,empty stem and mosaic disease.Therefore,this study analyzed the influence of different climatic factors on tobacco diseases in combination with the climatic conditions in Qianjiang area,and comprehensively evaluated the macronutrients of tobacco-growing soil types in order to provide a theoretical basis for effective prevention and control of tobacco diseases.Affected by land resources,it is difficult to achieve inter-annual crop rotation and fallow for flue-cured tobacco in the Qianjiang tobacco planting area of Chongqing.Long-term continuous cropping and continuous application of chemical fertilizers have resulted in soil compaction,poor permeability and nutrient imbalance.Therefore,it is of great practical significance to find environmentally friendly and effective soil improvement measures to prevent and control tobacco bacterial wilt,black shank,empty stem disease and mosaic disease in order to improve the quality of tobacco leaves.Through field trials,we compared the effects of oyster shell powder carbon-based fertilizer,earthworm manure and tobacco slow and controlled release integrated fertilizer on the incidence of tobacco bacterial wilt,black shank,empty stem and mosaic disease at the mature stage,and analyzed The effect of different amendments on the agronomic characteristics of tobacco at maturity stage,and the selection of suitable soil amendments.The results show that the application of carbon-based fertilizer in the soil has the best inhibitory effect on the occurrence and prevalence of bacterial wilt and black shank at the mature stage,with relative control effects reaching 34.49% and 31.84%;The application of oyster meal to the soil has a better inhibitory effect on the occurrence and prevalence of black shank,bacterial wilt and mosaic disease,and the relative control effects are 35.34%,30.03% and 20.61%.In terms of tobacco field growth,soil amendments have varying degrees of promoting effects on various agronomic characteristics of tobacco.Among them,the treatment of oyster meal and carbon-based fertilizer is more conducive to plant growth.