3种杀菌剂对小麦黑胚病菌的毒力测定及病害防治作用

采用分生孢子萌发率和菌落直径比较了3种杀菌剂对小麦黑胚病主要致病菌小麦根腐离蠕孢(B ip olaris sorok injana)和链格孢霉(A lternaria a lterna ta)的毒力作用,并在温室盆载和田间小区试验条件下进行了防治效果研究。结果表明,不同杀菌剂、同种杀菌剂不同浓度之间存在明显毒力差异。从分生孢子萌发率看,敌力脱浓度为0.250μL/mL时对小麦黑胚病2种病原菌分生孢子萌发抑制率高达99%以上,代森锰锌浓度为350μg/mL时的抑制率达94.5%以上,而多菌灵浓度为500μg/mL时的抑制率不到40%,远远低于以上两种药剂。从菌落直径看,敌力脱的致死中浓度(EC50)值最小,对小麦黑胚病菌菌丝生长的抑制作用最强。在小麦灌浆初期对温室盆栽和田间小区种植的感病品种丰舞981于人工接种前2 d和接种后4 d分别喷施3种杀菌剂,小麦黑胚率调查结果与室内抑菌实验结果相似,敌力脱和代森猛锌对小麦黑胚率有较好的控制作用,而多菌灵效果较差。接种病原菌后4 d喷药处理的防病效果明显优于接种前2 d的喷药处理。

Control of 3 fungicides against wheat black point in vitro and in vivo

The effects of 3 fungicides on conidia germination and mycelium growth of the pathogen, Bipolaris sorokinjana and Alternaria alternata and the cause of wheat black point were investigated in vitro and in vivo. The results showed that conidia germination and colony diameters were strongly inhibited by 3 fungicides in test concentration. The highest inhibitions were got from treatment of Propriconazole. Its EC50 values were very low. Carbendazim had less effect on the pathogens. Control of black point of wheat in greenhouse experiment and field trial by 3 fungicides revealed that Propriconazole and Mancozeb could effectively reduce the rate of diseased kernels compared with Carbendazim as well as untreated control after inoculation. Furthermore,much higher efficiency of disease control were found in 3 fungicides treatment 4 days after inoculation than that 2 days before inoculation.