Investigating abiotic and biotic factors affecting apple canker (Neonectria ditissima) symptom development

october 2021 – september 2025

Hamish McLean

Apple canker is caused by the fungal pathogen Neonectria ditissima. The pathogen infects the plant through wounds or leaf scars and grows under the bark. Infection often takes place in the nursery and can lie dormant for years before symptoms emerge. This PhD project is a continuation of recent work on apple canker at NIAB’s East Malling site and partner institutions, investigating the factors that affect infection and symptom development. Biotic factors are of particular interest because they offer potential control options. Understanding abiotic factors is important to predict how climate change will impact the disease.

For my first experiment, I will use metabarcoding to investigate the link between the rhizosphere microbiome and canker susceptibility in different apple cultivars. Secondly, I will conduct a pot experiment to investigate the effects of waterlogging on symptom development and use amendments to manipulate the microbiome. Finally, I will isolate and test some potential new biocontrol options.

Research progress

Hamish McLean AHDB Annual Report 2022

Hamish McLean AHDB Annual Report 2023