The use of forced heated air to manage botrytis stem blight of Geranium stock plants in a commercial greenhouse

The impact of forced heated air continuously applied ii om beneath an open-bottom bench on the incidence of Botrytis stem blight and inoculum production was assessed in a commercial greenhouse planting of geranium stock plants. The forced heated air treatment significantly reduced the incidence of stem blight and sporulation on blighted stems and necrotic leaves of stock plants compared to the control. This reduced incidence Di necrotic leaves with sporulating Botrytis cinerea with their concomitant decrease in fresh and dry weights al the end of the growing season for those plants exposed to forced heated air clearly shows the efficacy of this treatment. In addition, during days when grower activity was documented, B. cinerea conidial concentrations estimated using a Burkard recording spore trap were lower in the modified area than in the control area.