Effect of Bacteria Bacillus subtilis , Bacillus thuringiensis and Pseudomonas fluorescens in biological control of okra plant from the infection by Rhizoctonia solani fungus

	Effect of Bacteria Bacillus subtilis , Bacillus thuringiensis and Pseudomonas fluorescens in biological control of okra plant from the infection by Rhizoctonia solani fungus
Euphrates Journal of Agriculture Science
Article 1, Volume 5, Issue 4, 2013, Pages 464-480
Abstract
Abstract: The results of isolation and diagnosis of fungus from roots of okra plants indicated the existing of the fungi Rhizoctonia solani from eight locations in the province of Babylon. The preliminary tests of pathogenic for isolates were pathogen Showed as main tested by percentage of cabbage seeds germination 0-64%. Lathhous conditions pathogenicity test of eight isolates of R.solani (R.s1, R.s2, R.s3,Rs4,R.s5,R.s6 R.s7,R.s8). Using 40 days old okra plants as host plants showed that all isolated increased increment in disease severity which ranged between 30-94.75% compared to control (non-contaminated) though the disease severity was zero%. Under the lathhous condition the result of test of biocotrol agent Bacillus.subtitis + Pseudomonas.fluorescens and B.thuringiensis + P. fluorescens and B.subtilis + B.thuringiensis using okra plants 52 days old and presence of isolate pathogen (R.s2) showed that all treatment caused reduction in percentage of infection severity which ranged between 13.10%, 14.15% and 17.42%, respectively, compared to the control treatment pathogen (fungus alone) which shows aseverity of disease 94.75%. Under filed condition , the result of test for biocontrol agent B.subtilis + P.fluorescens and B.thuringiensis + P.fluorescens and B.subtilis+ B.thuringiensis using okra plants and presence of isolate pathogen (R.s2) showed that all treatment caused significant reduction in percentage of infection severity as it ranged 13.02, 15.12% and 18.37%, respectively, compared to the control treatment pathogen (fungus alone) which shows aseverity 91.32%. All elements caused significant increase in the criteria such as fresh , dry weights and lenghts of shoot and root and increased of fruit yield.treatment biocontrol agent of B.subtilis+ P.fluorescens was the best treatment which resulted incresing the productivity that reached 4.22kg/plant compared to the treatment when the fungus was used alone 0.85kg/plant.

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