不同杀菌剂对三七黑斑病菌的毒力测定

Toxicity Determination of Different Fungicides on Alternaria panax

三七黑斑病是三七的主要叶部病害,年均发病率在20%~35%之间,严重时可达90%以上。为筛选可用于田间防治的化学杀菌剂,选取福美双、氟硅唑、苯醚甲环唑、丙环唑、戊唑醇、百菌清、烯唑醇、异菌脲、代森锰锌、多菌灵和苯酰菌胺共11种化学杀菌剂原药,采用菌丝生长抑制法和孢子萌发抑制法测定了其对三七黑斑病菌的抑制作用。结果表明,苯醚甲环唑对病原菌菌丝的EC_(50)为0.004 mg/L,是供试杀菌剂中最低的,表明其对三七黑斑病菌敏感;丙环唑、戊唑醇、氟硅唑和烯唑醇的抑制作用较好;异菌脲、百菌清、福美双、苯酰菌胺和代森锰锌抑制效果较差;多菌灵的抑制作用最差,EC_(50)值在800 mg/L以上。孢子萌发抑制作用实验结果表明,代森锰锌对病原菌的EC_(50)值最小,为0.0067 mg/L,抑菌活性最高;百菌清和福美双的EC_(50)值分别为1.2855、5.2379 mg/L,抑制活性次之;丙环唑、氟硅唑、苯醚甲环唑和异菌脲的EC_(50)值10.6469~25.0169 mg/L之间,抑菌活性一般;苯酰菌胺和多菌灵的EC_(50)值分别为106.1958、199.9349 mg/L,抑菌活性较差;戊唑醇和烯唑醇的EC_(50)值为300 mg/L,抑菌活性最差。

Alternaria panax Wheltz is the main leaf disease of Panax notoginseng（Burk.） F H Chen. Theaverage incidence of Alternaria panax ranges from 20% to 35%, even up to 90% in some plantations. To screenthe appropriate fungicide for field control, eleven fungicides, including thiram, flusilazle, difenoconazole,propiconazole, debuconazole, chlorothalonil, diniconazole, iprodione, mancozeb, carbendazim, and zoxamide,were selected to determine their toxicity to Alternaria panax with mycelium growth inhibitory method and sporegermination inhibitory method. The results showed that EC50 of difenoconazole for pathogen hyphae was 0.004 mg/L, which was the minimum in all fungicides, indicating that difenoconazole was sensitive to Alternaria panax. Propiconazole, debuconazole, flusilazole and diniconazole had better inhibitory activity.Iprodione, chlorothalonil, thiram, zoxamide and mancozeb had worse inhibition activity, While carbendazim had the worst inhibitory activity with EC50 value over 800 mg/L. Spore germination inhibition results showedthat mancozeb had the best inhibition activity with the minimum EC50 value of 0.0067 mg/L, whilechlorathalonil and thiram had the second inhibition activity with EC50 value as 1.2855 mg/L and 5.2379 mg/L,respectively. Propiconazole, flusilazole, difenoconazole, and iprodione had normal inhibition activity with EC50 value ranged from 10.6469 mg/L to 25.0169 mg/L. Zoxamide and carbendazim had less inhibition activity with EC50 value as 106.1958 mg/L and 199.9349 mg/L, respectively. EC50 value of debuconazole and diniconazole to Alternaria panax were 300 mg/L, and the inhibition activity was the worst.