Combined use of Enterobacter cloacae MB20 and the microelements of copper and manganese to control damping-off of tomato

Abstract

Abstract Biocontrol activity of Enterobacter cloacae alone and in combination with copper and mangan on the suppression of tomato damping off was assessed. Rhizoctonia solani damping-off is difficult to control, since its dorman organ sclerotia survive for long periods under various environmental condition. The availability of micronutrients copper and mangan may play important roles in controlling of plant diseases. Results showed that the application of E. cloacae alone decreased damping-off of tomato significantly (P<0.05) by 85%. Combination application of E. clocae with 10μg ml−1 of CuSO4 showed the highest suppression of the disease, followed by the treatment of E. cloacae with 5μg ml−1, as high as 95% and 90% respectively, although the differences was not significant compared to other treatments. Degree of the disease suppression did not differ between application of E. cloacae alone and in combination with both concentration of MnSO4 (μg ml−1 and10μg ml−1), the disease decreased about 85%. Inoculation of R. solani alone into soil resulted significantly highest (P<0.05) of fungal population, it was about 33.7 x 103 CFU g−1 soil, and inoculation of R. solani and E. cloacae reduced significantly fungal population to about 19.0 x103 CFU g−1 soil. E. cloacae produced chitinase and protease, its chitinolytic index was about 0.84, and proteolytic index was 0.61.