Study On The Epidemic Pattern And Integrated Control Technology Of Tobacco Ralstonia In Yibin

Bacterial wilt is a typical bacterial soil-borne disease caused by Ralstonia solanacearum.It mainly harms Solanaceae crops,especially in tobacco areas in China.In Yibin tobacco areas,bacterial wilt is often mixed with tobacco black shank,which increases the difficulty of control measures.The occurrence area of tobacco bacterial wilt increases year by year,the harm become more serious,gradually spreading from low-altitude areas to high-altitude areas,which has become a constraint on the sustainability of flue-cured tobacco.This paper investigated the epidemic rule and key influencing factors of bacterial wilt in Yibin tobacco areas,evaluated the effects of different soil amendments on soil acidification and tobacco bacterial wilt,and studied the effects of different microbial combinations on tobacco bacterial wilt.The comprehensive prevention and control effect of tobacco wilt was finally integrated into a set of comprehensive tobacco wilt prevention and control technology systems applicable to Yibin tobacco areas,and applicability was evaluated,aiming to provide a theoretical basis for tobacco wilt prevention and control.The results obtained through research are as follows:1.Using systematic surveys and general surveys,combined with field experiments to investigate the occurrence of bacterial wilt and influencing factors.The results found that soil is the most important overwintering site for pathogens,and the accumulation of R.solanacearum in the soil is the cause of bacterial wilt.The basis of blight,high temperature and high humidity are the most important conditions for inducing bacterial wilt;water flow is the main transmission route of pathogens,and its transmission speed is much faster than soil;field farming operations can transmit a small amount of pathogens;Then we found that Yibin tobacco area could divided into four areas of accidental disease area,general disease area,frequent disease area,and frequent severe disease area.This is important for tobacco bacterial wilt control.2.Investigating the influence of different transplanting periods on the incidence of tobacco bacterial wilt.The results showed that different transplanting periods of flue-cured tobacco have a certain correlation with the incidence of tobacco bacterial wilt.And it is clarified that areas with severe bacterial wilt occur at an altitude of 800 meters.The best transplanting period is early April.3.The results of soil amendments showed that in areas with severe soil acidification,the use of oyster shell powder 1500kg/hm~2 or silicon fertilizer1200kg/hm2 or a combination of both is beneficial to improve the soil environment and increase soil PH,and control the tobacco bacterial wilt disease.4.By carrying out a three-factor comprehensive control experiment on ridge height,types of chemicals,and application methods,it was clear that ridge 30cm combined with substrate mixing bacteria and roots were continuously irrigated with Pseudomonas fluorescens twice after the trees(interval 10 days)The best control effect,the incidence rate of the area with serious bacterial wilt disease can be controlled at 57.5%,which has a significant effect on the control of tobacco bacterial wilt;30cm ridges combined with substrate mixing bacteria and used continuously after the trees The control effect of Bacillus polymyxa irrigated twice(interval of 10 days)is second,and the incidence of severe bacterial wilt disease area can be controlled at 60%;ridge 30cm combined with substrate and mixed with bacteria and used after fluorescence Pseudomonas irrigated once can control the incidence rate at 66.5%.5.Using integrated control measures of tobacco bacterial wilt(substrate mixing,increased application of oyster shell powder,increased application of organic fertilizer and precise medication),it can effectively promote the early growth and rapid growth of tobacco seedlings,and promote tobacco clustering and topping.At the same time,the control effect on tobacco bacterial wilt is particularly obvious,the control effect reaches89.01%during the harvest period,and it also has a certain control effect on tobacco black shank,with a relative control effect of 46.67%.