1996 Volume 62 Issue 6 Pages 559-565
Cyclamen petals were treated with a highly chitinolytic bacterium, Serratia marcescens isolate B2, and 24hr later, were challenge-inoculated with Botrytis cinerea conidia. The bacterium suppressed fungal disease incidence by ca. 60% on attached petals of cyclamen in the greenhouse. The efficacy of isolate B2 against gray mould caused by B. cinerea, which was resistant to benzimidazole and dicarboximide fungicides, was nearly equal to that of 200ppm of iprodione, a dicarboximide fungicide. Although isolate B2 failed to survive on petals and leaves more than two weeks after the initial application, populations on leaf discs placed on the soil near the base of the cyclamen plant, where gray mould regularly developed, increased 10-fold during this period. Cyclamen leaf discs were challenge-inoculated with B. cinerea conidia either 1hr, 3 days or 7 days after isolate B2 application, then placed near the base of the plant in the greenhouse. Fungal sporulation on the discs was suppressed by more than 85%. S. marcescens B2 was significantly more effective than iprodione treatment against fungal sporulation on the discs.
