Application of pyraclostrobin in disease control of wheat at different growth stages

In order to explore the feasibility of pyraclostrobin in preventing diseases of wheat at different growth stages, the virulences of pyraclostrobin against the causal agents of wheat sheath blight (Rhizoctonia cerealis), root rot (Bipolaris sorokiniana), total rot (Gaeumannomyces tritici), and head blight (Gibberella zeae) were determined by the mycelial growth rate method. Using the seed germination test, the effect of different concentrations of pyraclostrobin coating on wheat seed germination was determined. The control effects of pyraclostrobin 5% FS on wheat sheath blight in pots were determined by the bacteria-soil mixing method and the field control effects of pyraclostrobin 5% SC against R. cerealis, B. sorokiniana, G. tritici, and G. zeae were also determined. The results showed that the EC₅₀ value of pyraclostrobin against R. cerealis, B. sorokiniana, G. tritici, and G. zeae were 0.404, 5.862, 0.193, and 1.372 mg/L, respectively. Different coating ratios of pyraclostrobin 5% FS had a certain promotion effect on the fresh weight and dry weight of Jimai 22 under the condition of 25 ℃ and showed a certain promotion effect on the germination potential, germination rate, germination index, and vigor index of wheat seeds under the condition of 10 ℃. The pot experiment showed that pyraclostrobin 5% FS had a control efficacy of more than 74% on wheat sheath blight 20 days after seedling, and the control efficacy reached 99.02% when the coating ratio was 1∶50. The control efficacies of pyraclostrobin 5% SC on wheat powdery mildew, rust and scab were 100%, 100%, and 75.87% respectively under the dose of 3000 mL/hm² with two sprays during early flowering and full flowering periods. The research showed that pyraclostrobin can be well applied to the control of wheat diseases in different growth stages.