8种杀菌剂对核桃炭疽病病原菌胶孢炭疽菌的室内毒力

由胶孢炭疽菌Colletotrichum gloeosporioides引起的核桃炭疽病是目前危害山东省核桃生产的主要病害。为筛选防治该病害的高效药剂,在确定了最适菌丝生长和分生孢子萌发温度的基础上,采用菌丝生长速率法和孢子萌发法,测定了8种常用杀菌剂对胶孢炭疽菌的毒力,评估了温度对咪鲜胺和戊唑醇毒力的影响,检测了17个胶孢炭疽菌菌株对咪鲜胺和戊唑醇的敏感性,同时评价了这2种杀菌剂的预防和治疗作用。结果显示:在胶孢炭疽菌菌丝生长和孢子萌发的最适温度28℃下,供试8种杀菌剂中,咪鲜胺、戊唑醇和三唑酮对供试菌株菌丝生长的抑制作用最强,平均EC50值分别为0.07、1.45和3.04 mg/L;异菌脲、代森锰锌和咪鲜胺对分生孢子萌发的抑制作用最强,平均EC50值分别为21.07、25.14和25.18 mg/L。咪鲜胺对菌丝生长的抑制作用受温度影响较小,而戊唑醇对菌丝生长的抑制作用随温度降低而增强;供试17个菌株对咪鲜胺和戊唑醇均有较高敏感性,平均EC50值分别为0.08 和 1.03 mg/L。建议在核桃炭疽病发病的不同时期,轮换使用咪鲜胺、戊唑醇、三唑酮、异菌脲和代森锰锌等杀菌剂,以有效控制该病害。

Laboratory toxicity of eight fungicides against Colletotrichum gloeosporioides causing walnut anthracnose

Nowadays,walnut anthracnose caused by Colletotrichum gloeosporioides is the serious and mainly diseases of walnut orchards in Shandong province.The optimum temperature for mycelial growth and conidial germination of the tested strains was measurated,and the toxicity of eight fungicides against walnut anthracnose pathogen was determined by both mycelial growth rate test and conidial germination assay in laboratory.The toxicity of prochloraz and tebuconazole to four selected strains of C.gloeosporioides under different temperatures were determined and the sensitivity of all seventeen strains of C.gloeosporioides to prochloraz and tebuconazole were screened by mycelial growth rate test.Meanwhile the protective and curative effects of prochloraz and tebuconazole were evaluated.The results showed that the optimum temperature for mycelial growth and conidial germination of C.gloeosporioides was 28℃.Under 28℃,prochloraz,tebuconazole and triadimefon had maximum toxicity against mycelial growth of C.gloeosporioides with the average EC50 value of 0.07,1.45 and 3.04 mg/L,respectively;while iprodione,mancozeb and prochloraz had maximum toxicity against conidial germination with the average EC50 value of 21.07,25.14 and 25.18 mg/L,respectively.The toxicity of prochloraz against C.gloeosporioides was not influenced by temperature,while the toxicity of tebuconazole increased when the temperature decreased.All the seventeen tested strains of C.gloeosporioides showed high sensitivity to prochloraz and tebuconazole,with mean EC50 values of 0.08 and 1.03 mg/L,respectively.It was recommended that prochloraz,tebuconazole,triadimefon,iprodione and mancozeb could be used as effective fungicides for integrated management of walnut anthracnose.