Soil and rhizosphere scientist Dr Emma Tilston said: "It's a problem that comes from the soil but the soil aspect has been less studied - the focus has been on the choice of soil fumigants.
"The symptoms are more severe on light soils because the damaged roots are less able to take up water in response. ARD is a complex of lots of different pathogens, including Pythium and Phytophthora at the swimming stage, which favour wet soils, but also Fusarium and Rhizoctonia, which cause more lesions in drier soil.
"A really effective solution will be found from several strategies. We are focusing on the influence of rootstock genotype, which has been less studied. We know that if you replant at the same spot with the same rootstock the effects are very bad - M9 is particularly susceptible - but if you change the rootstock you can mitigate the effects."
The research at EMR "is very much about the latest molecular techniques to understand both the deleterious and beneficial microbes within the soil, which will help us develop more resistant rootstocks". ARD can delay fruit production by two or three years in new orchards and lower production by up to 60 per cent over a tree's lifetime.