Investigation of the possibility of biological control of sugar beet seedling damping-off in the green house using bacterial antagonists
2007
Asghar Heydari | Naraqi, Heydari
Rhizoctonia solani-induced sugar beet seedling damping off is one of the most important diseases of sugar beet in Iran. Since the causal agent of the disease is a soil borne fungus therefore, chemical control is not always effective. In addition, wide spread use of chemicals has resulted in pollution of the environment and appearance of resistant races of the pathogen. The need for the search of alternative methods to control this disease is therefore clearly obvious. Biological control could be a promising alternative method. In this study the possibility of biological control of the disease by bacterial antagonists was investigated. Fifty bacterial isolates, isolated from cotton and sugar beet field soil were first screened against Rhizoctonia solani in the laboratory using dual culture method. Ten isolates which showed highest effectiveness were selected for further evaluation in the green house experiments. In green house experiments the above isolates were tested against damping off disease caused by two isolates of R. solani using seed coating and soil drench methods. Analysis of the results showed that 5 out of 10 isolates were the most effective in reducing cotton seedling damping-off significantly (compared to the control). Of the above mentioned isolates, 4 isolates belonged to Bacillus spp. (B. subtilis and B. polymyxa each with two isolates) and the other isolate were identified as Pseudomonas fluorescense based on bacteriological identification tests.
显示更多 [+] 显示较少 [-]