Establishment of baseline sensitivity ofRhizoctonia solanito thifluzamide in maize and its field application

Abstract In recent years, banded leaf sheath blight in maize ( Zea mays L.) has become an important disease that seriously affects quality and yield. This paper aims to evaluate the sensitivity of Rhizoctonia solani Kuhn to thifluzamide on maize, to clarify the effect of seed coating using a thifluzamide suspension agent on safety and physiological indicators and to determine the effectiveness of control of banded leaf sheath blight in the field. In this study, the thifluzamide sensitivity of 102 strains of R. solani in maize from Shandong was determined using the mycelial growth rate method; the average half-maximal effective concentration value (EC 50 ) was 0.086 ± 0.004 μg/ml and displayed a unimodal frequency distribution, indicating that thifluzamide had strong inhibitory activity on the mycelial growth of R. solani in maize. In an indoor pot test, the root activities under 24 g a.i./100 kg seed were found to increase by 78.01%, compared with the control. Similarly, chlorophyll content increased most significantly at this dose, by 32.3%. Thifluzamide (FS) could significantly increase the per-plot yield. Among the examined dosages, 48 g a.i./100 kg seed had the most significant treatment effect, with the yield rate increasing by 15.7% and 14.1%, respectively, in 2017 and 2018 compared with the control. The field effectiveness against banded leaf sheath blight in maize was highest at the dosage of 48 g a.i./100 kg seed for a seed dressing with thifluzamide (FS). These results indicate that thifluzamide has enormous potential for controlling banded leaf sheath blight in maize.