| Abstract: | Xanthomonas fragariae spreads in symptomlessly infected strawberry plantlets and a method for detection of latent infections is necessary. It is a very slow‐growing bacterium in culture and is easily overgrown by saprophytic bacteria. Therefore, plating is not a suitable method for detecting low numbers of bacteria in symptomless plants. In addition, selective media are not available. Serological assays like immunofluorescence are useful for testing in‐vitro plants, but they are not suitable for field‐grown plants, as cross reactions are common with the available antisera. For these plants, nested PCR with primers from Pooler ( Pooler et al., 1996 ) and Zimmermann ( Zimmermann et al., 2004 ) has proved to be a valuable method. The method was successfully applied for a survey of strawberry plants from fields in Germany and for testing imported plants (frigo and green plants). |
