烟草麻孢根腐病菌生理学特性及药剂毒力测定

为明确烟草麻孢根腐病菌Gelasinospora reticulata的生理学特性及对杀菌剂的敏感性,采用十字交叉法和血球计数法研究了不同培养条件对该病菌菌丝生长的影响,并测定了11种不同杀菌剂对病菌的抑制作用。结果表明,该菌菌丝生长和产生子囊孢子的最适宜温度为26~32℃,最适生长pH为4;光照对菌丝和子囊孢子生长有明显的抑制作用;相对湿度高有利于该菌子囊孢子的萌发,当相对湿度高于98%时,萌发率达100%;温、湿度交互作用中,温度和相对湿度分别是影响菌丝生长和子囊孢子萌发的主要因素;不同碳源和氮源对菌丝生长及干重的影响差异显著,其中葡萄糖与酵母膏分别为最适宜碳源和氮源;病菌菌丝体和子囊的致死温度分别为51℃和55℃。咪鲜胺对该菌的抑制效果最好,EC_(50)为1.26μg/mL,其次是吡唑·醚菌酯,EC_(50)为2.78μg/mL,而代森锰锌、丙森锌、三唑酮和代森联抑制作用较差,不适合用于防治烟草麻孢根腐病。

Physiological characteristics of Gelasinospora reticulata and toxicity test of 11 fungicides

To clarify the physiological characteristics and sensitivity to different fungicides,the mycelial growth and ascospore production of Gelasinospora reticulata were determined by using the crossing and haemocytometer methods,and the inhibitory activities of 11 fungicides on G.reticulate were also studied.The results showed that the optimum temperature was 26-32 ℃,and pH value of mycelial growth was 4.The ascospore production was the best at 28 ℃.Light could inhibit the mycelia growth and ascospore germination.High relative humidity (RH) could promote the ascospore germination,when RH was higher than 98％,the rate of ascospore germination was up to 100％.The temperature and RH were the main factors on mycelia growth and ascospore germination.Effects for carbon and nitrogen sources on mycelia growth were significant difference,and the optimal carbon and nitrogen source for mycelia growth were glucose and yeast extract,respectively.The lethal temperature of mycelia and ascospore were 51 ℃ and 55 ℃,respectively.The effective concentrations for G.reticulate were obviously different,the inhibitory activity of prochloraz was the highest with EC50 of 1.26 μg/mL among all fungicides,and pyraclostrobin was the second with EC50 of 2.78 μg/mL.The inhibitory activities of mancozeb,propineb,triadimefon and metiram were lower and not suitable for controlling the Gelasinospora root rot.