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ARDERI – Apple Replant Disease Evolution and Rootstock Interaction
The UK’s apple producing and processing industry is currently growing due to a huge increase in cider consumption worth £3000M per year. Apples are the most important tree fruit grown in the UK, but despite the growth in the industry our annual crop of dessert and cider apples currently meets only a third of national demand.
Replant disease, whereby apple trees fail to thrive in soil where apples have previously been grown, can reduce the productivity of commercial orchards by 50% and is therefore a serious problem. The causal agents are thought to be several different types of pathogenic microorganism, whose effects are compounded by root-lesion nematodes. If the affected trees survive, they fruit late and produce fewer, low-quality fruit. The high economic costs of this disease to fruit growers and the nursery industry are worsening due to the adoption of high density orchard systems and changes in agri-chemical regulations.
Here at East Malling Research we are working with four industrial partners to:
- Unpick the diversity of pathogens that cause apple replant disease
- Understand interactions between organisms that cause replant disease and apple rootstocks
- Determine why some apple rootstocks are more resistant to the disease
- Investigate the legacy effects of growing rootstocks with greater disease resistance
This project will be an important step towards developing an integrated management system for apple replant disease. The team has received financial and in-kind support from two multinational companies and two UK apple producers, who recognise the great economic value of this research for their industry.
In addition to commercial horticulture, the use of improved, integrated approaches to managing replant disease will also benefit traditional and community orchards, which have significant environmental and social value.
Dr Nicola Harrison, Rootstock Biologist (left), Dr Emma Tilston, Soil Scientist (centre) and Felicidad Fernandez, Rootstock Breeder (right), among trees propagated for replicated trials on grower sites.
A healthy orchard
Orchard with stunted trees: a symptom of replant disease.
Scale: wooden posts are 2.5 meters high.