Detection Of Asymptomatic Branch Rotting Bacteria In Apples And Study Of Spore Transmission Law

In recent years,apple tree valsa canker has occurred in a large area in southern Xinjiang and has caused serious economic losses,from the new nursery young trees to the elderly trees have different degrees of incidence,and even the phenomenon of garden destruction.At present,a large number of studies have been carried out on the prevention and control technology of apple tree valsa canker and certain results have been achieved.However,the prevention and control measures are relatively passive,and the epidemic and development of the disease are not controlled from the root cause,and the analysis is mainly due to the latent infection characteristics of the rotting bacteria,and there is little knowledge about the tree carrier bacterium and the development law of the occurrence and development of the disease in the apple producing areas of southern Xinjiang,and it is impossible to predict the potential risk of the apple rot disease,resulting in the prevention and control of the rot disease to scrape off the spots,which is the main treatment measure,which is harmful to the tree and time-consuming and laborious.Therefore,this paper investigates the occurrence and development of asymptomatic branch carriers by detecting the carriers in apple orchards in different regions of southern Xinjiang,and studies the production and spread of conidia of apple tree valsa canker bacteria,the annual growth of diseases,and the annual expansion of disease spots,and explores the key meteorological factors affecting the spore transmission and development of apple tree valsa canker bacteria and the development of disease spots,which provides a theoretical basis for the prediction and comprehensive prevention and control of apple tree valsa canker in southern Xinjiang.Combined with the research content of this paper,the main conclusions are as follows:1.Detection of the bacterial rate of apple tree valsa canker in the main apple-producing areas of southern XinjiangThe asymptomatic branches of apple trees in the Bazhou,Hotan and Aksu regions of southern Xinjiang were studied,and the carrying rate of rotting pathogens was detected by Nested-PCR technology.The results showed that the asymptomatic branches of apple trees in three regions had different degrees of carriers,among which the average carrier rates of asymptomatic branches in Bazhou,Hotan and Aksu were67.1%,60% and 55.7%,respectively,and the carrying rate increased with the increase of tree age in different regions.2.Study on the production of conidia and spore propagation of apple tree valsa canker bacteria in southern XinjiangApple tree valsa cankerting pathogens can produce conidia throughout the year,May to July and September to October are the peak periods for conidia production,and from November to February of the following year,conidia produce less,indicating that rotting bacteria have not stopped active in the cold winter and hot summer,but with the change of environmental conditions,the vitality of pathogenic bacteria has also changed accordingly.Correlation analysis showed that temperature,humidity and rainfall were the main factors affecting the generation of conidia of rotting pathogens,among which the production of conidia of rotting pathogens was significantly positively correlated with temperature and humidity(P<0.01)and significantly positively correlated with rainfall(P<0.05).The conidia produced by apple tree valsa canker bacteria can be transmitted to all sides throughout the year,of which May to June is the peak period of spore transmission throughout the year,the conidia transmission is reduced after June,and the conidia transmission is the lowest in January.From the perspective of transmission height,conidia can be transmitted at a height of 0.5 m to 2.5 m from the ground,of which the conidia within 0.5 m to 1.5 m altitude spread more than 2 m to 2.5 m.Through correlation analysis with meteorological factors,it can be seen that the conidia transmission of apple saprophysis is closely related to humidity,rainfall and wind speed,of which rainfall has the greatest influence on spore transmission,showing a very significant positive correlation(P<0.01)and a significant positive correlation between humidity and wind speed(P<0.05).Therefore,apple tree valsa canker bacteria have conidia generation and conidia transmission throughout the year,but their main influencing factors are different,temperature and humidity are the main factors affecting the production of conidia,and conidia transmission is mainly affected by rainfall.3.Study on the annual growth and growth of apple tree valsa canker in southern XinjiangThe peak period for new spots occurs from May to June and September to October,and the lowest number of new spots occurs from December to February of the following year.Correlation analysis showed that temperature and rainfall were the key factors leading to the occurrence of rot disease spots,and there was a significant positive correlation between the two and the growth of rot diseases(P<0.05);The annual expansion of the spots was expandable,and the peak period of the expansion was From April to June and September to October,the winter spots of the whole year were the lowest expansion and the highest amount of spring spots.Correlation analysis with meteorological factors showed a significant correlation between humidity and spot expansion(P<0.05)and temperature and spot expansion(P<0.01).According to the comprehensive analysis,the occurrence of new spots throughout the year is similar to the expansion of spots,and the main influencing factors of the two are temperature.In addition,rainfall can also affect the production of new spots of rotting disease,and the expansion of rot spots is greatly affected by humidity.