花椒疮痂病的病原鉴定与防治药剂筛选

Pathogen identification and screening of fungicides for scab of Zanthoxylum bungeanum

[目的]明确花椒疮痂病的病原菌,筛选出对该病害具有较好防治效果的杀菌剂,为其田间防治提供指导。[方法]采用组织分离培养法从采集的花椒疮痂病叶中分离微生物,通过回接试验和柯赫氏法则,证明分离的微生物是否为引起花椒疮痂病的病原菌;通过形态学观察和分子生物学对花椒疮痂病病原菌进行鉴定;采用带毒平板法和田间试验筛选对花椒疮痂病具有良好防治效果的杀菌剂。[结果]经形态学和分子生物学鉴定,花椒疮痂病的病原菌为互隔交链孢(Alternaria alternata)。室内抑菌作用筛选结果表明,咪鲜胺和苯醚甲环唑对花椒疮痂病原菌的抑制作用最显著,其EC50值分别为0.016、0.027 mg/L。田间防效试验结果表明,供试药剂中75%百菌清WP1125 g a.i./hm^(2)和45%咪鲜胺EW 337.5 g a.i./hm^(2)对花椒疮痂病具有良好的预防效果,连续3次喷药后,2种药剂预防效果为87.92%和76.88%。45%咪鲜胺EW 337.5 g a.i./hm^(2)对花椒疮痂病具有一定的治疗效果,连续3次喷药后,防效为59.64%。[结论]花椒疮痂病由互隔交链孢侵染引起,百菌清作为预防药剂具有良好效果;咪鲜胺作为治疗药剂具有良好效果。

[Aims]This research aims to identify the pathogenic fungi of leaf scab of Zanthoxylum bungeanum,screen the fungicides with good control effect,in order to provide guidance for its field control.[Methods]Tissue isolation and culture method was used to isolate the microorganism of diseased leaves of Z.bungeanum.Reinoculation experiment and Koch's postulate were applied to verify the isolates.Morphological observation and molecular biological methods were used to identify the pathogens.Radial growth assay and field trials were employed to screen effective fungicides.[Results]Alternaria alternata was identified by morphology and molecular biology as the pathogen of leaf scab of Z.bungeanum.The results of laboratory screening showed that prochloraz and difenoconazole had the most significant inhibitory effect on A.alternata,with EC50 values of 0.016 and 0.027 mg/L,respectively.The results of field trials showed that chlorothalonil 75%WP at 1125 g a.i./ha and prochloraz 45%EW at 337.5 g a.i./ha had good preventive effect on leaf scab of Z.bungeanum.After spraying 3 times,the preventive effects of the two fungicides were 87.92%and 76.88%.Prochloraz 45%EW at 337.5 g a.i./ha had a curative effect of 59.64%on leaf scab of Z.bungeanum after spraying 3 times.[Conclusions]Leaf scab of Z.bungeanum is caused by A.alternata infection,and chlorothalonil has a good control effect as a preventive fungicide,while prochloraz has a good control effect as an curative fungicide.