Effect of bacillus subtilis and Pseudomonas fluorescens in reducing cucumber seed rot and seedlings death caused by Rhizoctonia solani and Fusarium solaniin green house conditions

Abstract EN

The study was conducted to evaluate the efficacy of two bacterial biological control agents controlling the pathogenic fungi that cause seed rot and seedlings death on cucumber growth in green house in Abbasiya, Al-Huraira, Al-Haidari and Qizwiniya towns in Najaf province.

Bacillus subtilis and Pseudomonas fluorescens were isolated from soils of the above areas and biochemically identified at ministry of science and technology.

The pathogenic fungi Rhizoctonia solani and Fusarium solani isolated from cucumber seeds that have been grown in gerrn house and diagnosed morphologically and molecularly using the PCR technique.

The results showed two bacterial isolates were highly antagonistic to R.solani and F.solani.

Results of the pot experiment showed the ability of both bacterial isolates introspecting cucumber plants from infection by R.

solani and F.

solani, in addition to their high efficiency in increasing the growth indicators (germination, total vegetation and root length, soft and dry plant weight and leg diameter) after 14 and 28 days post planting.

The field experiment in green house when testing the effect of two bacteria isplutes was showed increasing of the total chlorophyll content of leaves of cucumber plants at 28 days, especially when treated with P.

fluorescens was significant differed from the rest of treatments with chlorophyll content of 1027.3 mg.

1.

in addition that some bacteria was significantly increased the rate of plant contact of the major elements (total nitrogen ,total Phosphor, total potassium) NPK after 14 and 28 days of planting 2.9 and 3.55%.

The best treatment ofB.

subtilis + P.

fluorescens.

was significantly increased the total cucumber yield 6.185 kg / plant for 20 harvests, compared with the rest of treatments.