Welcome to Chinese Agricultural Science Bulletin,

Chinese Agricultural Science Bulletin ›› 2020, Vol. 36 ›› Issue (28): 124-130.doi: 10.11924/j.issn.1000-6850.casb20191100798

Special Issue: 水稻

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Co-toxicity and Field Control Efficacy of Mixtures of Pyrisoxazole and Fluazinam to Blast Fungus Magnaporthe grisea in Rice

Chen Hongzhou(), Zhang Jianhua, Yang Hongfu, Zhou Huafei, Miao Kang, Shu Zhaolin, Yao Kebing()   

  1. Zhenjiang Institute of Agricultural Sciences in Hilly Area of Jiangsu Province, Jurong Jiangsu 212400
  • Received:2019-11-05 Revised:2020-03-04 Online:2020-10-05 Published:2020-09-23
  • Contact: Yao Kebing E-mail:hongzc_2006@126.com;zjykb@163.com

Abstract:

To explore a new reagent for controlling rice blast, the co-toxicity and field control efficacy of mixtures of pyrisoxazole and fluazinam on Magnaporthe grisea in rice were measured. The indoor toxicity of pyrisoxazole, fluazinam and their seven mixtures on M. grisea in rice was detected by using mycelium growth rate method, and the field control tests of the optimum formulation to rice panicle blast was conducted. The results of indoor toxicity tests showed that the EC50 values of pyrisoxazole, fluazinam and their seven mixtures at the ratio of 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, and 1:4 on M. grisea were 1.4417, 0.5445, 0.2313, 0.2693, 0.1695, 0.4151, 0.2796, 0.3395 and 0.3428 μg/mL, respectively, and the synergistic coefficients were 4.69, 3.79, 5.49, 1.90, 2.46, 1.90, and 1.81, respectively. The mixture at the ratio of 2:1 had the highest synergism. The results of the field control efficacy showed that the control efficacy was in the following order: 30% pyrisoxazole·fluazinam SC 600 mL/hm 2> 30% pyrisoxazole·fluazinam SC 450 mL/hm2> 30% pyrisoxazole SC 450 mL/hm2> 75% tricyclazole WP 300 g/hm2> 30% pyrisoxazole·fluazinam SC 300 mL/hm2> 40% isoprothiolane EC 1200 mL/hm2> 30% fluazinam SC 450 mL/hm2, and their field control efficacy were 88.39%, 83.40%, 80.22%, 72.91%, 71.28%, 65.09%, and 60.79%, respectively, and all treatments were safe for rice growth. 30% pyrisoxazole·fluazinam SC 600 mL/hm2has excellent control efficacy on rice blast and is safe for rice growth, which can be developed as a rice blast control agent.

Key words: rice blast, pyrisoxazole, fluazinam, co-toxicity, control efficacy

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