How does Opa work on wheat?

Spraying OPA 50ml/ mu with water at the initial stage of wheat powdery mildew and rust can effectively control powdery mildew and rust by spraying twice with water consumption of 30-45ml/ mu according to the interval of 7-10 days. In the early stage of wheat flowering, 50ml/ mu of Opa was sprayed with water, and flowering occurred according to the development of the disease.