NY120 - Biological control of damping-off diseases in bedding plants

Summary-Fifteen isolates of bacteria, from potting media collected from South Australian plant nurseries and potting mix suppliers, were screened for ability to control damping-off disease caused by Pythium ultimum var. sporangiiferum. The screening was by two bioassays on seedlings of papsicum annuum grown in a pasteurized potting medium in a glasshouse or controlled environment growth chamber. Ten isolates reduced damping-off and increased shoot weights, at least as well as the fungicide propamocarb, in both experiments. Eight isolates also reduced damping-off in seedlings of Celosia argentea in another glasshouse experiment, and all 14 isolates tested increased shoot weights, but propamocarb had no significant effect on damping-off or shoot weight. In another glasshouse experiment, four bacterial isolates were applied at five different doses to pasteurized potting medium with or without P. u.