The use of a pre-harvest 1-MCP application to prevent green colour loss and reduce blush of Granny Smith apples

Many Granny Smith apples are harvested at a maturity not suitable for export markets due to loss in green skin colour. Some Granny Smith orchards may also experience unwanted pink blush on the fruit resulting in reduced export pack outs.

The aim of this project was to determine if pre-harvest sprays of 1-MCP can prevent green skin colour loss and pink blush on Granny Smith apples

A Granny Smith orchard in the Koue Bokkeveld region was subjected to a 1x and 2x pre-harvest

1-MCP application ± 28, 14 and 3 days before commercial harvest. Green skin colour was assessed at spray and at harvest and after storage by means of maturity evaluation and commercial pack out.

Pre-harvest application of 1-MCP resulted in more fruit falling into the greener categories of the South African colour chart for green apples and pears. Commercial pack out data also confirms this with more fruit in the greener categories compared to untreated fruit. No trends were noted regarding pink blush.

Pre-harvest 1-MCP application resulted in retarded green skin colour degradation pre-harvest and post-harvest. The most effective application was a 2x application within 3 – 5 days before commercial harvest

Pre-harvest 1-MCP can be applied at optimum maturity, close to commercial harvest, to retard green colour loss during storage.