Detection And Identification Of Pathogenic Fungi In Import Podocarpus Macrophyllus With Soil

With the development of economy and the raising of people’s living standard, people’s demand for nursery stock, flowers and potted landscape plants is increasing constantly. A large number of new high-quality plant resources are continually introduced from abroad. Law of the Entry and Exit Animal and Plant Quarantine clearly stipulates that all soil is prohibited from entering, because a variety of animal and plant pathogens, insect larvae, ovum and weed seeds can be spread through the soil, and harmful organisms in the soil are detected difficultly. In order to crack down on the illegal imports of landscape plants with soil like Podocarpus macrophyllus and Pinus thunbergii Parlatore to prevent the plant epidemic incoming diffusion, meanwhile supporting the introduction of foreign high-quality plant resources to meet the needs of the domestic market, pest risk analysis for imported plant with soil have been conducted repeatedly in the state authorities to introduce foreign seedlings with soil at country-specific ports. This article focuses on detection and identification for dangerous pathogenic fungi and oomycetes carried by import Podocarpus macrophyllus with soil. The research results are as follow:9species in3genera of pathogenic fungi were separated and identified on samples of soil,which was obtained from the rhizosphere of Podocarpus macrophyllus imported from Japan.via rDNA ITS analysis based on traditional morphological identification. Among them,6species of Pythium are Pythium spinosum Sawada, Pythium irregulare Buisman. Pythium aphanidermatum (Edson) Fitzpatrick, Pythium vexans de Bary, Pythium dissotocum Drechsler and Pythium sylvaticum Campbell&Hendrix,1specie of Phytophthora is Phytophthora melonis Katsura and2species of Fusarium are Fusarium equiseti (Corda) Sacc and Fusarium tricinctum (Corda) Sacc. No Rhizoctonia is detected. Except9species of fungi which have been identified, some strains lack the basis of morphological identification as their sporophore can not be produced. These9species of fungi are not listed in the Catalogue of Quarantine Pest for Import Plants to the PRC, but it does not mean that Podocarpus macrophyllus imported with soil are absolutely safe and reliable. According to the quarantine rules, regular follow-up tracking and detection is still needed during isolation cultivation in order to obtain firsthand epidemic materials. The results of the study have verified preliminarily major fungal species in soil and the correspondingly effective detection method. Certain technicals of fungal diseases will be established for the inspection and quarantine of plant imported with soil in the future. It contributes to selecting comprehensive quarantine methods to fit plant quarantine in port, improves detection rate of pests, especially pathogenic fungi as well as enhances validity of port guard. Hence, this study is of actual significance and practical application value to promote high-quality seedlings with soil entering the domestic smoothly and safely.