海南番木瓜炭疽病病原菌鉴定及其防治药剂筛选

Pathogens Identification and Fungicide Screening of Papaya Fruit Anthrocnose in Hainan

【目的】为了明确番木瓜炭疽病主要病原菌种类及适宜的防治药剂。【方法】从海南采集番木瓜炭疽病病果,采用柯赫氏法则对病原菌进行分离、纯化、致病性测定,根据病原菌的形态特征,结合其rDNA-rrs区域的序列分析对病原菌进行鉴定,并采用生长速率法测定17种杀菌剂对该病原菌生长的抑菌活性。【结果】从分离的炭疽菌中,得到2种强致病菌(代表菌株分别为C1和G1),其中C1菌株与辣椒炭疽菌(Colletotrichum capsici)形态特征相似,G1菌株和胶抱炭疽菌(C.g/oeospcri

[Objective]The objective of this study is to identify pathogens causing typical anthracnose symptoms of papaya fruit in Hainan province and screen the effective fungicides to control them.[Method]These pathogens are isolated,purified and pathogenicity-tested by Koch's Rule.The pathogens were identified by their morphological characteristics and the sequence analysis of the internal transcribed spacer region of the ribosmal DNA(ITS).The inhibitory activities of 17 fungicides to these two pathogens were determined by the mycelial growth rate method.[Result]The isolate Cl and Colletotrichum capsici had similar morphological characteristics,while the isolate G1 and C.gloeospcrides had similar morphological characteristics.ITS sequences of them were amplified with universal primers of ITS1/ITS4.By sequence comparison with the related sequence in GenBank.It showed that the nucleotide homogeneity of the isolate Cl and C.capsici reached 99%,while the isolate G1 and C.gloeospcrides also reached 99%.The studies of toxicity test showed that 500 mg/mL prochloraz WG had the best inhibition to the mycelial growth of two pathogens,which the average of EC5q values was 0.03 jxg/mL,followed by 300 mg/mL fludioxonil SC and 250 mg/mL propiconazole EC.The average of EC50 values were 0.04 and 0.11|ig/mL.[Conclusion]It is concluded that the pathogens of papaya fruit anthrocnose are caused by C.capsici and C.gloeospcrides.500 mg/mL prochloraz WG,300 mg/mL fludioxonil SC and 250 mg/mL propiconazole EC have efficiently inhibitory effect on anthrocnose of papaya fruit.