Controlling fungus on Cripps Pink apples

A recent study of the effect of two pesticides on Phylctema vagabunda, a fungus that causes significant post-harvest losses of the Cripps Pink apple cultivar, revealed interesting results. Dr Alana den Breeyen and Dr Julia Meitz-Hopkins explain.

- Dr Alana den Breeyen and Dr Julia Meitz-Hopkins

Apple growers in the Western Cape suffer significant post-harvest losses due to the fungus Phylctema vagabunda, which infects the Cripps Pink apple cultivar. Worldwide, the fungus forms part of the bull’s eye rot disease complex on pome fruit. Currently, not much is known about the distribution of the fungus or the extent to which the disease is present on Cripps Pink apples in the Western Cape.

In a recent study published in the journal Plant Disease, Jessica Rochefort, a master’s student in the Fruit and Postharvest Pathology Programme (FPPP) at Stellenbosch University (SU), confirmed the presence and determined the incidence of P. vagabunda on stored commercial Cripps Pink apples in the major apple-growing regions of the Western Cape over three seasons, namely 2010/2011, 2011/2012 and 2012/2013. The FPPP is led by Dr Cheryl Lennox of SU’s Department of Plant Pathology.

P. vagabunda infects the lenticels of apples in the orchard, and symptoms appear only after months in storage. A molecular detection tool to determine when the fungus is present on Cripps Pink apples and pollinator trees in the orchard was developed as part of the same study.

The results showed that