Pest Risk Analysis And Important Pathogenic Fungi Isolation And Identifiction On Imported Sorghum

At present,the inspection and quarantine of sorghum in the United States mainly focuses on the contents listed in the list of quarantine pests of imported plants,without corresponding key objects of attention and without corresponding pertinence,which increases the introduction risk of foreign pests.Therefore,it is particularly important to re-evaluate the risk of imported sorghum.This paper analyzed the diversity of fungi in imported sorghum samples by consulting various authoritative databases and literature materials,and determined 139 pathogenic fungi that could be imported with sorghum.After screening,there are 13 kinds of quarantine pests that need further risk analysis.In addition,a strain named A009 which was suspected as Fusarium thapsinum was isolated from imported u.s.sorghum seeds.The main research results are as follows:1.The Pest Risk Analysis of 139 imported sorghum pathogenic fungi had been completed.After screening,there are 13 quarantine pests that need further risk assessment,namely Choanephora cucurbitarum、Claviceps africana、Claviceps sorghi、Colletotrichum sublineolum、Gloeocercospora sorghi、Mycosphaerella holci、Periconia circinata、Peronosclerospora spontanea、Phoma glomerata、Phoma sorghina、Puccinia purpurea、Ramulispora sorghi and Ramulispora sorghicola.2.Further risk assessment of 13 kinds of quarantine pests on sorghum was conducted.The importance of quarantine was determined from five aspects:geographical distribution,possibility of entry into China,possibility of colonization in China,possibility of diffusion in China and economic impact assessment.Among them,5 pathogenic fungi with high quarantine importance were Claviceps africana、Colletotrichum sublineolum、Gloeocercospora sorghi、Periconia circinata and Phoma glomerata.3.Strain A009 isolated from imported sorghum seeds was determined to be Fusarium thapsinum after morphological identification,molecular identification and pathogenicity test.This study also found it has strong pathogenicity and it will be a potential threat to the sorghum industry,so we should strengthen quarantine on it.