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Crown gal disease, caused by Rhizobium radiobacter (formerly known as Agrobacterium tumefaciens), is one of the most important bacterial plant disease of stone fruits, pome fruits, grape vine, vegetable and ornamental plants distributed worldwide. Disease causes considerable damage in nursery and young orchards of variety of plants including apple where grower may suffer serious economic losses as galled plants show growth reduction and yield. Different control measures have been used against crown gall as a dipping of rooted plants into chemicals, soil fumigation, soil solarization and biological control. The aim of this study was to determine biocontrol efficacies of epiphytic and endophytic bacteria, obtained from apple roots and crowns, against crown gall disease agent. Eighty five putative epiphytic and endophytic antagonist bacterial isolates were obtained from the apple rhizosphere, roots and crown. By using dual culture test, putative antagonist bacterial isolates were screened for their ability to suppress disease agent R. radiobacter in vitro conditions. According to the results obtained from the preliminary dual culture test, 12 isolates, belonging to different bacterial species of Pseudomonas, Pantoea, Serratia and Bacillus genus were found to cause clear inhibition zones of 5.0-27.3 mm diameter. Among the tested antagonist isolates, three different bacterial isolates of Pseudomonas putida 1-4en, 1-12en and 1-13en were then chosen for semi in vivo studies which were conducted on carrot slice assay. Among these isolates, the most efficient bacterial isolate 1-14en significantly suppressed gall formation on carrot slices. Results of this study revealed that antagonist bacterial isolates of Pseudomonas putida has potential as biocontrol agent for crown gall disease caused by Rhizobium radiobacter [ABSTRACT FROM AUTHOR]

Grapevine has an importance gradually increasing with various cultivars of grapevine in Central Anatolia Region. With the aim of determining of bacterial diseases, the researches were carried on 14 various cultivars of grapevine and in 24 district of Konya Province in 2007-2008. In the identification of bacterial gall disease, Agrobacterium vitis, growth on Roy and Sasser, King's B, PDA mediums, growth at 37 °C, 3-ketolactose production, growth on 2% NaCl, production of alkaline from L- tartaric acid and malonic acid, using of citrate, at pH=4,5 pectolytic activity, at pH=7 motility, litmus milk test, acid from erythrytol and melesitose, ferric ammonium citrate, acid cleaning on PDA+CaCO3 tests were based. In the pathogenicity tests, it was observed formation of gall typically in the result of bacterial inoculation with 108 cfu/ml concentrations on seedlings of grapevine cultivar Sultani Seedless, tomato and sunflower plants. It was made amplification of pehA and virA genes by PCR for molecular identification. While A. vitis was determined on 280 plants from totally 309 plant samples, the most of isolates had been observed tumorogenic character. Obtaining the results, rate of incidence has been as 90.61% has big importance and within all of the cultivars, pathogen was shown the most on cv. Sultani Seedless, cv. Cardinal, cv. Hafizali and at the least on cv. Sour Black in the province. [ABSTRACT FROM AUTHOR]