Investigations of antimicrobial effect of some endemic species of Labiatae family on important plant pathogenic bacteria

Various control strategies have been investigated for growing plants which are free of plant diseases and pests in our country as the entire world. One of these strategies is that diseases and pests are controlled by using plant materials and extracts. In this study scope, the anti-microbial effects of essential oils of Origanum minutiflorum O. Schwarz & P. H . Davis, Sideritis erytrantha Boiss.& Heldr. apud Bentham subsp. erytrantha, Salvia tchihatcheffii (Fisch.& Mey.), Satureja wiedemanniana (Lalem.) Velen and Thymus sipyleus Boiss subsp. sipyleus which are endemic species plants belonging to Labiatae family were tested against the twenty bacteria caused diseases on plants. Under in vitro conditions, trials were done on common medium and inhibition zone diameters formed by essential oils were determined. Inhibition zone diameters ranged from 0 to 54 mm. Additionally the minimum inhibition concentrations (MIC) of these essential oils were determined. It was found that the lowest MIC score was 125 ?g/ml and the most MIC score was >500 ?g/ml. In the results of chemical analysis, it was determined that the main ingredient of O. minutiflorum essential oil was Carvacrol with the rate of 73,93 % and the main ingredients of Sideritis erytrantha subsp. erytrantha essential oil were g- terpinene, b-caryophyllene and Sabinene with the rate of 17,75 %, 11,81 and 9,96 %, respectively. Additionally, the main ingredients of Salvia tchihatcheffii essential oil were 1,8-cineole and Camphor with the rate of 44,45 % and 12,19 % respectively. Also the main ingredients of Satureja wiedemanniana essential oil were p-cymene, Menthadiene and Spathulenol with the rate of 11,55 %, 9,45 % and 7,22 respectively and the main ingredients of Thymus sipyleus subsp. Sipyleus essential oil were 1,8-cineole and Camphor with the rate of 44,98 % and 12,19 %, respectively. The effect of essential oil of O. minutiflorum which was found to be the most effective oil in the result of in vitro trials was tested against the bacterium of Xanthomonas vesicatoria. This trial was performed on tomato plants grown in climate room which had constant conditions. Five different characters were used in the trials. Firstly, the essential oil was applied on tomato plants. After 48 hours, the bacterium of Xanthomonas vesicatoria was applied on the same plants. In the result of the assessment done according to 0-4 scale, it was found that the disease caused by this bacterium was inhibited with the rate of 81.25 %. The different among the characters was found to be important according to the results of variance analysis and was determined 3 different groups. Key words : Labiatae family, endemic species, essential oil, antimicrobial effect, plant pathogenic bacteria.