New method for testing tomato seeds for Clavibacter michiganensis subsp. michiganensis and Xanthomonas campestris pv. vesicatoria
A new method has been developed in Israel to test tomato seeds for the presence of several seed-borne pathogens of tomato. Especially Pseudomonas syringae pv. corrugata, Xanthomonas campestris pv. vesicatoria (EPPO A2 organism) and Clavibacter michiganensis subsp. michiganensis (EPPO A2 organism) can be detected by this method. The method employs dry grinding, weighing, bacterial extraction and quantitative calculation on selective or semi-selective medium and enables the detection of as few as 10 colony forming units per gram of tomato seed bacteria in a 7 g tomato seed sample. With this method several seed lots which had phytosanitary certificates according to visual inspections during the growing occasion could be demasked as they were infested by one or several of the mentioned bacteria.
Sources
Kritzman, G. (1991) A method for detection of seedborne bacterial diseases in tomato seeds.
Phytoparasitica 19, 133-141