Leaf blackening is a major problem for the cutflower Protea industry. Leaves often show symptoms of blackening as soon as 3 days after harvest. Presence of the disorder significantly decreases the vase life of the flowers as well as decreases returns to the grower.
This report is an extension of the work conducted by Crick and McConchie (1999) who found that stems treated with gaseous ethanol, had less than 20% of leaves blackened for a period of 18 days. In the present project a range ethanol and other alcohol concentrations were assessed, as well as various methods of applications such as gaseous application, the use of slow release sachets and addition of ethanol to vase water.