Pathogen Identification And Seed Treatment Technology Of Bacterial Disease On 2 Kind Of Melon

Cucumber(Cucumis sativus L.)is an annual creeping and climbing plant of Cucurbitaceae,and is cultivated all over China.As one of the main vegetable varieties in China,it can be cultivated in greenhouse,plastic greenhouse and open field.Watermelon(Citrullus lanatus(Thunb.)Matsum.et Nakai)is an annual vine,there are many advantages,in which the sarcocarp is sweet and delicious,the pericarp has the functions of clearing away heat,diuresis and reducing blood pressure,and the seeds can also be used as leisure food.Therefore,watermelon is favored by consumers and widely cultivated almost in the whole country.Due to the increase of consumption of cucumber and watermelon in Jilin Province,the planting and production area of cucumber and watermelon has been increased so as to meet the needs of consumers.However,with the promotion of planting area,the corresponding diseases have been gradually emerged.In this paper,through the identification of pathogens causing main bacterial diseases of cucumber and watermelon in 2018 and2019 in Jilin Province,as well as the exploration of chemical control methods of corresponding pathogens,several chemicals that can significantly inhibit the corresponding bacterial pathogens were selected.This study provides a theoretical basis for effective prevention and control of bacterial diseases in the production of cucumber and watermelon.The results of this study are as followed:1.The diseased leaves and fruits of cucumber bacterial diseases were collected in Biangang Town,Dehui City,Jilin Province,the diseased fruits of watermelon bacterial diseases were collected in Nong’an County,Jilin Province,and the specimens of leaf spot disease were collected in Zhenglan Town,Qian’an County,Jilin Province.The disease samples collected above were tested in the laboratory,and the corresponding isolates were obtained by the streak separation method.After further Koch’s postulating,the obtained isolates were determined to be the pathogens of the corresponding diseases.2.With the method of molecular biology,we identified the pathogen of bacterial disease of cucumber collected in Dehui City was Pseudomonas syringae pv.lachrymas;the pathogen of bacterial disease of watermelon collected in Nong’an County was Acidovorax citrulli,which causing the disease is called bacterial fruit spot disease of watermelon;the bacterial disease of watermelon leaves collected from Qian’an County was Pseudomonas syringae pv.syringae,the disease is designed bacterial leaf spot disease of watermelon,which is first found in China.3.The inhibition zone method was used to detect the sensitivity of Pseudomonas syringae pv.Lachrymas and Acidovorax citrulli.Three bactericides with better inhibition effects on the two pathogens were screened out.Agent A,albendazole 20%EC and pseudomonas fluorescens3000*10~8/g.4.The feasibility of seed treatment with three bactericides were determined.The results showed that the inhibition rate of fungicide A to watermelon and cucumber seeds was 100%when treated with 50 times solution and 100 times solution before sowing for 60 minutes,and there was no adverse effect on germination of cucumber and watermelon seeds.There were no inhibition of the other two bactricides to these 2kind of pathogens.