Various control strategies have been investigated for growing plants which arefree of plant diseases and pests in our country as the entire world. One of thesestrategies is that diseases and pests are controlled by using plant materials andextracts. In this study scope, the anti-microbial effects of essential oils ofOriganum 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 weretested against the twenty bacteria caused diseases on plants. Under in vitroconditions, trials were done on common medium and inhibition zone diametersformed by essential oils were determined. Inhibition zone diameters rangedfrom 0 to 54 mm. Additionally the minimum inhibition concentrations (MIC) ofthese essential oils were determined. It was found that the lowest MIC score was125 ?g/ml and the most MIC score was >500 ?g/ml.In the results of chemical analysis, it was determined that the main ingredient ofO. minutiflorum essential oil was Carvacrol with the rate of 73,93 % and themain ingredients of Sideritis erytrantha subsp. erytrantha essential oil were g-terpinene, b-caryophyllene and Sabinene with the rate of 17,75 %, 11,81 and9,96 %, respectively. Additionally, the main ingredients of Salvia tchihatcheffiiessential oil were 1,8-cineole and Camphor with the rate of 44,45 % and 12,19% respectively. Also the main ingredients of Satureja wiedemanniana essentialoil 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 mosteffective oil in the result of in vitro trials was tested against the bacterium ofXanthomonas vesicatoria. This trial was performed on tomato plants grown inclimate room which had constant conditions. Five different characters wereused in the trials. Firstly, the essential oil was applied on tomato plants. After 48hours, the bacterium of Xanthomonas vesicatoria was applied on the sameplants. In the result of the assessment done according to 0-4 scale, it was foundthat 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 theresults of variance analysis and was determined 3 different groups.Key words : Labiatae family, endemic species, essential oil,antimicrobial effect, plant pathogenic bacteria.

Bütün dünyada oldugu gibi ülkemizde de hastalık ve zararlılardan ari ürünyetistirmek için çesitli mücadele yöntemleri denenmektedir. Bu yöntemlerdenbiri, bitkisel materyaller ve bitkisel ekstraktlar kullanılarak hastalık vezararlılarla mücadele etmektir. Bu çalısma kapsamında Labiatae familyasınaait endemik türler olan Origanum minutiflorum O. Schwarz & P. H . Davis,Sideritis erytrantha Boiss.& Heldr. apud Bentham subsp. erytrantha, Salviatchihatcheffii (Fisch.& Mey.) Boiss., Satureja wiedemanniana (Lalem.) Velen. veThymus sipyleus Boiss. subsp. sipyleus bitkilerinin uçucu yaglarınınantimikrobiyal etkisi, bitkilerde hastalık olusturan yirmi bakteriye karsıdenenmistir. Denemeler invitro kosullarda besi ortamı üzerinde yapılmıs veuçucu yagların olusturdukları inhibisyon zon çapları belirlenmistir. Olusaninhibisyon zon çapları 0-54 mm arasında degismistir. Ayrıca bu uçucu yaglarınbakterilerin gelisimini engelledigi en düsük konsantrasyonlar (MIC)belirlenmistir. MIC degerleri en düsük 125 ?g/ml, en yüksek ise >500?g/mlbulunmustur.Kimyasal analizler sonucunda, Origanum minutiflorum uçucu yagının anabilesenini % 73,93 oranla Carvacrol, Sideritis erytrantha var. erytrantha uçucuyagının ana bilesenlerini % 17,75 g-terpinene, % 11,81 b-caryophyllene ve %9,96 Sabinene maddelerinin olusturdugu belirlenmistir. Bunun yanında, Salviatchihatcheffii uçucu yagının ana bilesenleri % 44,45 oranla 1,8-cineole ve %12,19 Camphor'dur. Ayrıca Satureja wiedemanniana uçucu yagının anabilesenlerini % 11,55 p-cymene, % 9,45 Menthadiene ve %7,22 Spathulenol veThymus sipyleus subsp. sipyleus uçucu yagının ana bilesenlerini % 44,98 1,8-cineole ve % 12,19 Camphor'dur.nvitro denemeleri sonucu en etkili bulunan O. minutiflorum bitkisinin uçucuyagının etkisi, Xanthomonas vesicatoria bakterisine karsı denenmistir. Budeneme sabit kosullardaki iklim odasında yetistirilen domates bitkileri üzerindegerçeklestirilmistir. Denemelerde bes farklı karakter kullanılmıstır. lk olarakuçucu yag domates bitkilerine uygulanmıstır. Kırksekiz saat sonraXanthomonas vesicatoria bakterisi aynı bitkiler üzerine uygulanmıstır. 0-4skalasına göre yapılan degerlendirme sonucunda, Xanthomonas vesicatoriabakterisi tarafından olusturulan hastalıgın % 81,25 oranında engellendigi tespitedilmistir. Yapılan varyans analizi ile de karakterler arasındaki farkın önemlioldugu ve 3 farklı grup olustugu belirlenmistir.Anahtar Kelimeler : Labiatae, endemik türler, uçucu yag,antimikrobiyal etki, bitki patojeni bakteriler.