MacDonald Campus of McGill University, 21 111 Lakeshore, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
Station de Pathologie Végétale, INRA d' Avignon, 84143, Monfavet, Cedex, France
Horticultural Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Boulevard, St-Jean-sur-Richelieu, Quebec
A semi-selective medium containing maltose, methyl green, and antibiotics (MMG) was developed for the isolation of Xanthomonas campestris pv. vitians. The semi-selective medium was evaluated based on plating efficiency of X. campestris pv. vitians in cell suspensions of pure cultures from leaves and soil. MMG medium allowed recovery of 5.7 to 30.6% of the X. campestris pv. vitians colonies recovered on nutrient agar and 0.1 to 8.4% of those recovered on 1/10-strength tryptic soy agar. MMG inhibited growth of most background bacteria and allowed reliable identification of X. campestris pv. vitians. The semi-selective medium contained (per liter) maltose (10 g), tryptone (5 g), K2HPO4 (3.5 g), KH2PO4 (2.75 g), trace elements (0.02 to 1.0 mg), methyl green (2 ml of a 1% aqueous solution), amoxicillin (32 mg), cephalothin (32 mg), cycloheximide (50 mg), and agar (15 g).