一种火龙果病原真菌的分离鉴定与杀菌剂筛选

Isolation and Characterization of a Pathogenic Fungal from Pitaya and Fungicide Screening

为了鉴定火龙果的病原菌,本文从火龙果发病枝条分离病原体,通过菌丝和孢子形态学观察、核糖体rRNA基因序列分析鉴定和回接实验,首次在海南发现火龙果感染溃疡病,其病原菌为新暗色柱节孢(Neoscytalidium dimidiatum);随后,分别用多菌灵、精甲霜.锰锌、氰烯菌脂、甲基托布津、达科宁(百菌清)等5种常见杀菌剂在培养基上进行抑菌实验,从抑菌圈的大小初步鉴定多菌灵为该病害的有效杀菌剂,为指导生产上的化学防治提供了选择杀菌剂的重要依据.

Pitaya is one of the most famous tropical fruits.Since the beginning of this year,serious plant diseases appear in pitaya orchard in Hainan province.Disease symptom showed colorless spots on the pitaya branch at the beginning state,and chlorosis and rotting appeared later.To identify the pathogen,we isolated the microorganisms from the diseased tissue from pitaya branch.Three bacteria and one fungus were isolated.To further identify which kind of microorganism caused the pitaya disease,we inoculated 4 potential pathogens to pitaya branches and found that it was the fungus that caused the disease.The pathogen was preliminarily identified as Neoscytalidium dimidiatum through ribosomes rDNA sequencing.Furthermore,five fungicides were used to test fungicide resistance of N.dimidiatum on screening medium,carbendazim was identified as the most effective fungicide for N.dimidiatum,which lay the theory foundation for chemical treatment of pitaya N.dimidiatum in practice.