BIOLOGICAL CONTROL OF POST HARVEST APPLE FRUIT ROT BY PSEUDOMONAS SYRINGAE

M. Saleh, Nahida; A. Fattah, Farkad

	BIOLOGICAL CONTROL OF POST HARVEST APPLE FRUIT ROT BY PSEUDOMONAS SYRINGAE
The Iraqi Journal of Agricultural Science
Article 1, Volume 43, Issue 0, 2013, Pages 103-113
Authors
Nahida M. Saleh; Farkad A. Fattah
Abstract
This study was carried out to isolate effective local microorganisms against apple fruit rot fungi. Two hundred and fifteen isolates of bacteria and yeasts were isolated from soil under apple trees, leaf and fruit surfaces from different apple orchids in Baghdad. Six of these isolates only were antagonistic to Rhizopus stolonifer and Penicillium sp., the causal agents of apple fruit rot on PDA and NYDA culture media. The most promising isolate, BN-33 was from apple fruit Cv. Anna. This isolate was identified as Pseudomonas syringae according to morphological, cultural, the ability to produce flourcent die and growth on some differential culture media. The identification to species level was assisted by the Central Laboratory, Ministry of Health, Baghdad, Iraq. Isolate BN-33 was significantly (P=0.05) effective against R.stolonifer Penicilliun sp. with 80 and 51% fruit rot reduction, respectively. Different concentrations of autoclaved or bacterial filter sterilized culture filtrate of isolate BN-33 significantly (P=0.05) reduced spores germination of Pencillium sp. with 9.05–33.58 and 9.57–35.75% compared with 96.18 and 95.11% for control treatments, respectively. These treatments also significantly (P=0.05) caused reduction of spores germination tubes length with 4.68–34.7 and 4.3–32.68 µm compared with 52.63–49.88 µm for control treatments, respectively. Liquid culture of the bacterium containing living cells was more effective against spores germination and germ tubes growth. This treatment prevented spores germination of R. stolonifer at all test concentrations. Antagonism was more effective as the time of R. stolonifer inoculation was delayed. This was manifested by the prevention of infection for even 7 days when the pathogenic fungus was added 24 for hour after isolate BN-33.

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