We developed a new method to detect Acidovorax avenae subsp. citrulli in watermelon seeds, by modifying the membrane filter immunostaining method, which was developed to detect Burkholderia glumae in rice seeds. The detection threshold of this new method for A. avenae subsp. citrulli was several cfu per 100 ml phosphate buffer using 1000 commercial watermelon seeds. Living cells of A. avenae subsp. citrulli could be obtained by stamping the membrane on selective medium plate before immunostaining.
