Identification Of Lotus Disease,Fungicides Screening And LAMP Detection Of Lotus Blackhead Disease

Among the three types of lotus in China,lotus with the main purpose of producing lotus seeds is called seed lotus.Seed louts is one of the most important aquatic economic crops in China,which combines the functions of ornamental,food and medicine,and has been loved by people since ancient times.Seed louts has a long planting history in China,and it is found that its planting history is nearly 3,000 years through the research of related recorded historical materials.At present,there are large-scale cultivation in more than 10provinces in China,such as Hubei,Jiangxi,Hunan,Fujian,Zhejiang,etc.It is reported that the total area of cultivation in various places is more than 120,000 hm²every year,which has become a characteristic and advantageous industry in many places.In the process of growth and production of seed louts,the growth and yield are affected by many factors,among which the loss of lotus seed yield caused by various diseases is the most serious.In this paper,the field diseases of seed louts were investigated,and three fungal diseases and one bacterial disease were identified and screened in laboratory.The disease cycle of seed louts blackhead disease and the construction of LAMP detection system were also discussed.The research results are summarized as follows:1.From 2019 to 2021,further investigation of lotus field diseases was carried out in white lotus science and technology expo park in Guangchang county,Jiangxi province and lotus fields in nearby towns,and four seed lotus diseases were preliminarily identified by pathogenicity determination,morphology and molecular biology research methods.Until then,there were no reports at home and abroad.Among them,three are fungal diseases,two diseases are caused by leaves（Alternaria alternata and Nigrospora pyriformi）,and one disease is caused by lotus（Fusarium proliferatum）.One is bacterial disease（Serratia marcescens）,which occurs in lotus seeds.2.Fungal diseases of three seed lotus plants were screened by mycelium growth rate method.The results showed that the best inhibitory effect on A.alternata was 56%boscalid-oxime proxetil suspension with EC₅₀value of 8.294μg·m L^-1.The best inhibitory effect on F.proliferatum was 40%difenoconazole suspending agent,with EC₅₀value of7.573μg·m L^-1.45%prochloraz emulsion in water has the best inhibitory effect on N.pyriformi,and its EC₅₀value is 11.488μg·m L^-1.The laboratory screening test of the pathogen of blackhead disease in seed lotus was carried out by coating counting method.The results showed that 20%zinc thiazole suspending agent had the best inhibitory effect on S.marcescens,and its EC₅₀value was 25.83μg·m L^-1.3.In view of the hidden characteristics of blackhead disease in seed lotus,which is difficult to detect in advance,the loop-mediated isothermal amplification technology（LAMP）was used to design the LAMP primer and construct the LAMP visual reaction system for its pathogen S.marcescens.The optimized system can detect whether there is S.marcescens in the sample at a constant temperature of 65℃,and it can be picked and picked in lotus seeds by rapid reaction for 45 min.4.According to the fact that the field incidence of blackhead disease in seed lotus is similar to that in Riptortus pedestris Fabricius,the R.pedestris Fabricius was detected by indoor bacterial isolation and LAMP detection technology,and it was speculated that R.pedestris Fabricius was the main vector of blackhead disease in seed lotus,and the corresponding control measures were put forward for the transmission route of blackhead disease in seed lotus,so as to provide effective early warning and prevention for blackhead disease in seed lotus.