芝麻茎点枯病菌的生物学特性及9种杀菌剂对其抑制作用测定

Biological Characteristics of the Pathogen of Sesame Stem Blight and Inhibitory Effects of Nine Fungicides

为了有效防治芝麻茎点枯病,对芝麻茎点枯病菌的生物学特性进行研究,并测定了9种杀菌剂的室内毒力。采用常规鉴定和分子鉴定相结合的方法,鉴定致病菌株为菜豆壳球孢[Macrophomina phaseolina（Maubl.）Ashby]。对菌株的生物学特性研究结果表明,最适合菌丝生长的培养基为PSA,碳源为蔗糖,氮源为胰蛋白胨;适合菌丝生长的p H值为5.02-6.22;菌丝生长的最适温度为28-30℃,致死温度为59℃;12 h光暗交替有利于菌丝生长。采用菌丝生长速率法测定了9种杀菌剂对该菌株的室内毒力,结果显示,9种杀菌剂对芝麻茎点枯病菌菌丝的抑制效果有很大的差异,12.5%烯唑醇WP、50%多菌灵WP、40%氟硅唑EC的抑菌效果较好,相应的EC50值分别为0.06、0.18、0.21μg/m L;抑菌效果最差的是70%恶霉灵SP,EC50值为33.61μg/m L。

The biological characteristics of the pathogen of sesame stem blight and the indoor toxicity of nine fungicides were studied. Using morphological identification and molecular identification,the isolated strain was identified as Macrophomina phaseolina( Maubl.) Ashby. The results of biological characteristics on M. phaseolina showed that the suitable medium for the mycelium growth was PSA,the most suitable carbon source and nitrogen source were sucrose and tryptone; the optimum temperature for the mycelium growth was 28—30 ℃,and the mycelium death temperature was 59 ℃; the optimum p H value for the mycelium growth was 5. 02—6. 22; the suitable light condition for the mycelium growth was L∶ D = 12∶12. The toxicity of nine kinds of fungicides against the M. phaseolina was measured by growth velocity in lab. The results revealed that the inhibitory effects of nine fungicides had great difference on the mycelium growth.12. 5% Diniconazole WP,50% Carbendazim WP and 40% Flusilazole EC had higher inhibitory effect.The EC50 values of these fungicides were 0. 06 μg / m L,0. 18 μg / m L and 0. 21 μg / m L. The inhibitory effect of 70% Hymexazol SP was the lowest,with EC50 value of 33. 61 μg / m L.