Apple canker
Novel approaches to controlling apple canker NIAB’s Matevz Papp-Rupar and Scott Raffle describe the latest research on apple canker, which is hoped to reduce the severe impact of the disease. Apple canker caused by the pathogen Neonectria ditissima, continues to give rise to 10%-20% tree losses per year in young orchards, in the early years after establishment, and it is still considered one of the highest priorities for research by UK apple growers. Previous NIAB research funded by AHDB (Project TF 223) used the biocontrol product Trianum G (Trichoderma harzianum) in newly planted orchards and stoolbeds. The product showed some promise in reducing the incidence of canker development, but it is currently only authorised for use on protected crops. This project also demonstrated that secateurs incorporating a chemical dispenser to treat pruning wounds, achieved significant reductions in canker number. Applying Folicur (tebuconazole) either alone or in combination with BlocCade (a physical acting barrier to spore germination) gave best results.
A more recent AHDB project led by NIAB at East Malling demonstrated that a Trichoderma based biocontrol product and a conazole based fungicide offered some decrease in canker incidence on infected trees, but only at lower inoculum levels of naturally infected wounds. As the biocontrol product is only authorised for use on grapevines and the conazole fungicide is not currently authorised on any crops in the UK, further research is urgently required. Working with Agrovista and Avalon Fresh, NIAB is currently benefiting from a Growing Kent & Medway funded research project to explore novel approaches such as biocontrol, alternative spray programmes, and soil amendments for improved tree health and resilience, with the hope of improving canker management practices. Branch dieback caused by Neonectria ditissima
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