CULTURE IN-VITRO OF RHODODENDRON AND ERYSIPHE SP

Successful dual cultures of a powdery mildew pathogen and Rhododendron ponticum plantlets were achieved using a tissue culture technique. Sp orulation was observed within 1 week of inoculation. Comparative in vi tro cultures were grown at 10, 15 and 20 degrees C with host tissue tr ansferred to fresh media at 2-monthly intervals. Viable conidia capabl e of infecting host tissue in vivo were obtained from cultures maintai ned at 10 and 15 degrees C after culture for more than 6 months. Isola tes from three sources (Auchincruive, Benmore and Perth) were introduc ed into culture. Cultures inoculated with Perth and Benmore isolates e xhibited increased host growth at 10 and 15 degrees C, respectively co mpared with control plantlets. These effects may result from pathogen- induced changes to host regulatory metabolism. The culture technique a llows the long-term maintenance of pathogen cultures under sterile con ditions without requiring subculture.