防治向日葵黑斑病杀菌剂的筛选

Screening of fungicides for controlling sunflower black spot

[目的]为筛选防治向日葵黑斑病的高效防治药剂。[方法]采用室内抑菌活性测定与田间防治对比试验相结合的方法,研究评价了8种不同杀菌剂对向日葵黑斑病菌丝生长及分生孢子萌发抑制作用及田间对向日葵黑斑病的防治效果。[结果]室内药剂抑菌活性测定结果表明:8种杀菌剂中对菌丝生长抑制作用最强的药剂是咯菌腈,EC_(50)值达到1.8078 mg/L;8种杀菌剂中对病菌分生孢子萌发抑制作用最强的药剂是己唑醇,EC_(50)值达到0.3025 mg/L。田间防治试验结果表明,8种杀菌剂中对向日葵黑斑病防效最好的药剂处理为25%吡唑醚菌酯EC 84.38 g a.i./hm^(2),防效达到86.19%,其次是10%己唑醇AS 45.00 g a.i./hm^(2)处理,防效为78.34%。[结论]吡唑醚菌酯、己唑醇是防治向日葵黑斑病具有应用潜力的药剂品种。

[Aims]This study aims to find out the fungicides with high efficacy to control sunflower black spot.[Methods]The activities of 8 fungicides against the fungal pathogen Alternaria helianthi were tested by mycelium growth rate and spore germination rate methods in laboratory,meanwhile,their control effiacy against sunflower black spot generated by A.helianthi was evaluated through field trials.[Results]The inhibition results showed that fludioxonil most significantly inhibited mycelium growth of A.helianthi among 8 fungicides,with EC_(50) of 1.8078 mg/L.Hexaconazole most significantly inhibited spore germination of A.helianthi among 8 fungicides,with EC_(50) of 0.3025 mg/L.The field trial results showed that pyraclostrobin 25%EC 84.38 g a.i./ha was the best with control efficacy of 86.19%for the sunflower black spot control among the tested 8 fungicides.Followed by hexaconazole 10%AS 45.00 g a.i./ha,with control efficacy of 78.34%.[Conclusions]Pyraclostrobin and hexaconazole are both potential fungicides for controlling sunflower black spot.