Pathogen Identification And Their Sensitivity To Bactericides For Bacterial Diseases On Five Medicinal Plants In Jilin Province

Six new diseases about bacterial soft rot of horn lian (Typhonium giganteum Engl.) andmilk thistle (Silybum marianum (L.) Gaertn.), bacterial leaf margin blight of woad (Isatistinctoria L.), bacterial leaf spot of Angelica sisnensis, bacterial top blight and black stem diseaseof safflower (Carthamus tinctorius L.) were firstly reported in Jilin province of China. Thesympotoms of the six diseases were described in detail. What was more, the taxonomic status ofthe pathogens were initially identified through pathogenicity, cultural, physiological andbiochemical properties, G+C content，as well as16S rDNA sequence analysis according to thereference 《Laboratory guide for identification of plant pathogenic bacteria》3rd edition.Sensitivities of some pathogens to bactericides were also studied.By above methods, the pathogens of bacterial soft rot of Typhonium giganteum Engl. andSilybum marianum (L.) Gaertn. were identified as Pectobacterium carotovorum subsp.carotovorum.The pathogen of leaf margin blight disease of Isatis tinctoria L. was identified asErwinia rhapontici. The pathogen of bacterial leaf spot of Angelica sisnensis was identified asErwinia rhapontici. The pathogen of top blight disease of Carthamus tinctorius L. wasidentified as Pseudomonas syringae pv. syringae. The pathogen of bacterial black stem diseaseof Carthamus tinctorius L. was identified as Pseudonomas cichorii. Six diseases have not beenreported in the world, so Typhonium giganteum Engl., Isatis tinctoria L., Angelica sisnensis,Carthamus tinctorius were new record hosts of their pathogens.The bactericides were screened indoor for controlling bacterial soft rot of Typhoniumgiganteum Engl. and Silybum marianum (L.) Gaertn., bacterial leaf margin blight of Isatistinctoria L., bacterial leaf spot of Angelica sisnensis and bacterial top blight disease ofCarthamus tinctorius L. by inhabition zone method.300billion/g Pseudomonas fluorescens wasthe most effective bactericide.72%SPX Streptomycin and20%2-Bromo-2-nitro-1,3-propanediol WP had better inhibitory effect for the five pathogens. The results provided ascientific basis for prevention and treatment of the five diseases in the field.