Abstract: To elucidate the dosage reduction of tebuconazole （Teb） and efficacy enhancement effects of different plant immune inducers in the control of rice sheath blight, five plant immune inducers, including chitosan （CHI）, amino oligosaccharide （CHS）, abscisic acid（ABA）, oligosaccharide plant activator （OPA）, acetylsalicylic acid （ASA） and ethephon（ETH）, were chosen the combine with Teb and sprayed twice during the rice booting stage （5~7 days before heading） and heading stage respectively. The results showed that in combination with a 20% reduction of Teb, all inducers except ETH significantly improved the control effect. Combinations with ASA and ABA exhibited control effects of 95.2% and 93.2% against rice sheath blight, respectively, significantly higher than the full dosage of Teb treatment, with enhancements of 41.5% and 38.5%. In combination with a 50% reduction in Teb, the control effects of the treatments of ASA, OPA, ABA, and CHS were higher than the full dosage of Teb treatment, but the improvements were not significant. The actual yield results indicated that under the condition of a 50% reduction, all except CHS, OPA, ASA, and ETH had no adverse effects on yield. Therefore, within a certain range, ABA, CHS, and OPA could act as combination partners to reduce the usage of Teb and enhance its efficacy in controlling rice sheath blight.

Key words: plant immunity inducer, tebuconazole, rice sheath blight, reducing quantity and increasing efficiency