Title: Study on the effect of mixed-use of selected antagonistic bacteria isolates in combination with chemical inducers on optimum control of rice sheath blight in field conditions
Author: Mehdi Rostami Daroonkela
Abstract: Sheath blight disease caused by Rhizoctonia solani AG1-IA is one of the most important rice diseases in high-yielding cultivars in the rice cultivation areas of the North of Iran. The present study was conducted to investigate the effect of selected antagonistic bacterial isolates, in combination with chemical resistance inducers on optimum control of rice sheath blight in field conditions. From Pseudomonas mosselii, P. protegens, P. aeruginosa, and Bacillus spp. species were used in combination with each other and potassium silicate and oxalic acid as chemical inducers. The effect of treatments on the development of the disease in the booting stage was assessed by measuring the occurrence and severity of the disease by counting the number of infected tillers and the measurement of relative lesion height (RLH) on the plant. The data were analyzed using SAS 9.3 version. The mixture of Pseudomonas spp. in combination with potassium silicate and also a mixture of Bacillus spp. in combination with oxalic acid reduced the disease at the booting stage by 48.52% and 43.75 respectively in the field conditions. They were determined as the best treatments in optimal control of the disease. Propiconazole (Tilt) reduced the disease by 36.89 % and like the two mentioned treatments were placed in the same statistical group. Therefore, a mixture of Pseudomonas spp. isolates in combination with potassium silicate and a mixture of Bacillus spp. isolates in combination with oxalic acid were determined as the best treatments for optimal control of the disease.
Keywords: Pseudomonas spp., Bacillus spp. , Potassium silicate, Oxalic acid, Biological control