The Identification Of Pathogenic Of Peony Root And Stem Fungal Diseases

Tree peony (Paeonia suffruticosa Andrews; Paeoniaceae) is one of the traditionalflowers in China. As we all know, Luoyang has been a famous peony country sinceancient times, and now it becomes an important peony cultivated center in China, evenin the World. However, with the increase of peony species and the expansion ofplanting areas, species of disease hazards show an ascendant trend. All above had aserious impact for the peony’s ornamental value and medicinal value. In order toinvestigate the peony root and stem fungal diseases, we selected the Chinese Garden,Country Peony Garden, International Peony Garden, Peony Park and the other majorpeony plantations to study. These fungal were isolated from diseased roots andstems with typical symptom, cultured by single spore isolation and tested forpathogenicity according to Koch’s postulation, and identified according tosymptoms and morphology, combined with rDNA-ITS sequence.According to the field investigation, symptoms diagnosis and the pathogenidentification, we found three kinds of peony root fungal diseases. They were Peonywhite silk disease (Sclerotium rolfsii Succ.), Penoy damping off disease (Rhizoctoniasp. AG-A) and Peony root rot disease [Fusarium solain (Mart.) Sacc.] which was themost serious diseases. We also found six kinds of peony stem fungal diseases. Theywere Peony red spot disease (Cladosporium paeoniae Pass), Peony tumor spot disease[Pilidium concavum (Desm.) H hn.], Peony grey mould disease (Botrytis paeoniaeOudem), Peony ring spot disease (Pestalotiopsis paeoniae Serv.), Peony cankerdisease (Botryosphaeria sp.) and Peony branch blight disease (Phoma sp.、Diplodiasp.、Seiridium sp.、et al.). Among them with peony canker disease and peony branchblight disease onset heaviest.Based on the morphological characteristics, rDNA-ITS sequence analysis andpathogenic determination, the pathogen of Peony canker disease was identified as B.dothidea (Moug.) Ces. et de Not., phorozoon was Fusicoccum aesculi Corda. The pathogen of Peony branch blight disease was identified as P. glomerata (Corda)Wollenw.&Hochapfel, teleomorph was Mycosphaerella; Diplodia mutila Fr.,teleomorph was B. stevensii Shoemaker; Seiridium ceratosporum (De Not.) Nag Raj;Stagonospora nodorum (Berk.) Castellani&E. G. Germano, teleomorph wasPhaeophaeria nodorum E. Müler. Several kinds of pathogens were familiar pathogens,but they could also infect peony caused canker disease and branch blight disease, hasnot yet reported.Those fungi which isolated from diseased roots and root necks with typicalsymptoms, were cultured by sift, purifi and test for pathogenicity from the body. Basedon the morphological characteristics, rDNA-ITS sequence analysis, the pathogen ofPeony root rot disease was identified as F. solani, which accounting for more than80%of the fungi, and this result was consistent with the previous reports. Other fungi suchas F. oxysporum, F. eguiseti, Rhizoctonia and Pestalotiopsis often mixed with F. solani,made the root rot disease aggravated.In this study, Peony root and stem fungal diseases were further identified based onmorphological characteristics and rDNA-ITS sequence analysis. The results indicate B.dothidea, P. glomerata, D. mutila, S. ceratosporum and S. nodorum are new pathogenson Peony in our country. This study will provide theory evidence on the accuratediagnosis and effectively prevent of the peony disease.