Potential Inoculum Sources of Tomato Stem and Pith Necrosis Caused by Pseudomonas Viridiflava in the Eastern Mediterranean Region of Turkey

Abstract

Stem and pith necrosis caused by Pseudomonas viridiflava is one of the important diseases of tomato grown in greenhouses in Turkey. The pathogen causes general wilting and yellowing and brown-black spotting near the pruned areas on tomato stems. The survival period of P. viridiflava was investigated with a rifampicin-resistant strain (AD-OZ3a Rif(+)) in contaminated soil, plant debris and on seeds in the eastern Mediterranean region. AD-OZ3a Rif(+) was recovered from plant debris (10 cm below the soil surface) 8 months later for 2 years. The bacterium survived in contaminated soil during 6 and 5 months in 1999 and 2000, respectively. When contaminated tomato seeds were sown in the sterile soil, cotyledons of the seedlings became diseased by P. viridiflava. The pathogen was located on the surface of the tomato seeds after artificial inoculation. Treatment with sodium hypochlorite eliminated the pathogen on the seeds. Isolated bacteria from plant debris, soil and seedlings were identified as P. viridiflava by morphological, physiological, biochemical, pathological, serological rests and wholecell fatty acid analysis using the MIS gas chromatography system.