Occurrence of bacterial spot disease, caused by Xanthomonas axonopodis pv. vesicatoria, on pepper in the eastern Mediterranean region of Turkey

Y. Aysan^1* and F. Sahin^2,3

¹ Department of Plant Protection, Faculty of Agriculture, Cukurova University, 01330 Balcali, Adana , Turkey.
² Department of Plant Protection, Faculty of Agriculture, Ataturk University, 25240 Erzurum, Turkey.
³ Biotechnology Research and Application Center, Ataturk University, 25240 Erzurum, Turkey.

*aysanys@mail.cu.edu.tr

Accepted for publication 06/03/03

During the summers of 1999 to 2002, a survey of commercial pepper fields was conducted in the eastern Mediterranean (Adana and Osmaniye) region of Turkey. All the pepper fields planted with a local cultivar (cv. Salcalik) were found to be infected with a bacterial spot disease (Fig. 1).

Figure 1. Typical symptoms of bacterial spot caused by
Xanthomonas axonopodis pv. vesicatoria on pepper.

Disease incidence was estimated to be in the range 50-95%. A yellow-pigmented bacterium was consistently isolated onto Tween medium (Mcguire et al., 1986) from diseased pepper plants grown in 82 different fields. Thirty representative strains selected were gram-negative, rod shaped, motile, aerobic, oxidase negative, catalase positive and amylolytic positive. All of the strains were identified as Xanthomonas axonopodis pv. vesicatoria (Doidge) Dye (Xav) (similarity 66 to 94 %) using fatty acid methyl ester (FAME) analysis and Sherlock Microbial Identification System software (Microbial ID, Newark, DE, USA) (Bouzar et al., 1994, Jones et al., 1998). They all produced positive hypersensitive reactions on tobacco (Nicotiana tabacum cv. Samsun), and were pathogenic on pepper (cv. Salcalik) and tomato (cv. H-2274) plants. Xav strains were also recovered from seed lots of cv. Salcalik. This result suggested that the primary inoculum source of the disease was contaminated seed used in this region. Occurrence of Xav on pepper grown in the eastern Anatolia region of Turkey has been reported previously (Sahin, 2001), but this is the first report of the observation of Xav in the eastern Mediterranean region of Turkey.

References

Bouzar, H, Jones, JB, Stall, RE, Hodge, NC, Minsavage, GV, Benedict, AA, Alvarez, AM, 1994. Physiological, chemical, serological, and pathogenic analyses of a worldwide collection of Xanthomonas campestris pv. vesicatoria. Phytopathology 84, 663-671.

Jones, JB, Stall, RE, Bouzar, H, 1998. Diversity among xanthomonads pathogenic on pepper and tomato. Annual Reviews of Phytopathology 36, 41-58.

Mcguire, RG, Jones, JB, Sasser, M, 1986. Tween media for semi-selective isolation of Xanthomonas campestris pv. vesicatoria from soil and plant material. Plant Disease 70, 887-891.

Sahin, F, 2001. Pepper races 7, 8 and 10 of Xanthomonas axonopodis pv. vesicatoria isolated from diseased pepper plants in Turkey. Plant Pathology 50, 809.

The British Society for Plant Pathology