织金县南瓜炭疽病菌的分离鉴定及防治药剂筛选

Isolation,Identification and Fungicide Screening of Pumpkin Anthracnose Pathogen in Zhijin County

【目的】明确织金县南瓜炭疽病的病原菌株类型及有效防治药剂,为该病害的防控提供理论依据。【方法】采用形态学观察、分子生物分析及致病性测定相结合的方法,对从当地南瓜种植区采集的南瓜病样进行病原菌分离、鉴定,在此基础上对市场上常见的8种杀菌剂(60%唑醚·代森联WG,10%苯醚甲环唑WG,30%肟菌酯SC,1%申嗪霉素SC,450 g/L咪鲜胺EW,70%丙森锌WP,22.5%啶氧菌酯SC,50%嘧菌酯WG)进行筛选。【结果】分离得到2株引起南瓜病害的病原菌N-1和N-2,回接试验表现与田间发病症状基本一致;通过病原菌形态学联合ITS、ACT、GADPH基因的PCR扩增、序列分析和系统发育树,菌株N-1、N-2与短孢炭疽菌(Colletotrichum brevisporum)处于同一分支,支持率达100%,确定分离得到的病原菌为短孢炭疽菌;室内药剂筛选出60%唑醚·代森联WG 4000倍液、10%苯醚甲环唑WG 4000倍液及450 g/L咪鲜胺EW 4000倍液对菌株有较好的抑制效果,抑制率分别为88.6%、91.5%和89.0%,极显著高于其余5种药剂。【结论】引起织金南瓜炭疽病的病原菌为短孢炭疽菌,60%唑醚·代森联WG、10%苯醚甲环唑WG及450 g/L咪鲜胺EW可用作南瓜炭疽病田间防治的候选药剂。

【Objective】To provide the theoretical basis for control of pumpkin anthracnose by identifying the type of pathogenic strain causing pumpkin anthracnose and screening the effective fungicides against pumpkin anthracnose in Zhijin County.【Method】The pathogen samples causing pumpkin anthracnose in pumpkin planting area are isolated and identified by using the methods of morphological observation,molecular biological analysis and pathogenicity identification.The antibacterial effect of 8 common fungicides(60%Pyraclostrobin Metiram WG,10%Difenoconazole WG,30%Trifloxystrobin SC,1%Shenqinmycin SC,450 g/L Prochloraz EW,70%Propineb WP,22.5%Picoxystrobin SC and 50%Azoxystrobin WG)on Colletotrichum brevisporum is determined to screen the effective fungicides to control pumpkin anthracnose.【Result】Two pathogenic strains(N-1 and N-2)causing pumpkin anthracnose are isolated and their disease performance is the similar to the disease symptom in the field basically by a back infestation test.The strain N-1,strain N-2 and C.brevisporum are in the same branch by pathogenic morphology,PCR amplification and sequence analysis of ITS,ACT and GADPH and structure of the phylogenetic tree and their homology is up to 100%.Strain N-1 and Strain N-2 are identified as C.brevisporum.The inhibition rate of 60%Pyraclostrobin Metiram WG(4000×),10%Difenoconazole WG(4000×)and 450 g/L Prochloraz EW(4000×)against two isolated strains reaches 88.6%,91.5%and 89.0%separately,which is very significantly higher than other 5 fungicides.【Conclusion】The pathogen causing pumpkin anthracnose is identified as C.brevisporum.Three screened fungicides of 60%Pyraclostrobin·Metiram WG,10%Difenoconazole WG and 450 g/L Prochloraz EW are used as candidate fungicides in prevention and control of pumpkin anthracnose in the field.