Abstract: Phenazine-1-carboxylic acid （PCA） was prepared into water-soluble liquids with NaOH, KOH, NH₃ and isopropylamine, respectively, and the stability and indoor toxicity of each formulation were tested. The soluble liquids of PCA isopropylamine salt were screened out, then the field trial of rice sheath blight control was carried out. The results showed that after cold storage, hot storage and room temperature storage, the 4 soluble liquids were the most stable in storage at room temperature. The degradation rates of PCA isopropylamine salt, PCA ammonium salt, PCA potassium salt and PCA sodium salt were 0.82%, 1.64%, 1.41% and 1.49%, which respectively had good stability. The EC₅₀ of four water-soluble preparations of PCA isopropylamine salt, ammonium salt, potassium salt, sodium salt and PCA original drug to control the mycelia of Rhizoctonia solani were 19.994 0, 21.489 9, 23.953 6, 23.953 5, 19.235 4 μg/mL. Field test results showed that when the dosage of the preparation was 1 050 g/hm², the water-soluble solution of shenzinomycin and isopropylamine had the highest control effect against rice sheath blight in the field, reaching 84.35%, which was better than the 1% PCA suspension agent.

Key words: phenazine-l-carboylic water-soluble liquid, toxicity, stability, Rhizoctonia solani, control effects