Strategies to reduce sooty mould infection in organic apple production (BIOFRUITNET Practice Abstract)

Summary in the original language of the document

The risk of infestation is lower when the orchard is in airy areas and when early-maturing varieties are used.
Practical recommendations
Preventive measures keep the orchard in dry conditions:
• The crown of the trees must be managed so that they do not become too dense.
• Mow the grass under the row by making frequent passes.
• Avoid all factors that prolong leaf wetness and increase humidity.
• Avoid overhead irrigation systems. Prolonged wetting of the leaves increases the risk of attack.
• Avoid aphid infestations. The honeydew produced by aphids increases the risk of sooty mould infection.
• Avoid using leaf fertilisers (algae preparations or nitrogen compounds, including organic ones).
• Avoid excessively humid conditions during storage.
• The most used plant protection products are copper, lime sulphur, potassium bicarbonate and sodium. The efficacy is currently unclear as pathogens are different and vary from region to region.
• Soap-based treatments are carried out. It also has an indirect action against fumigants, as it can dissolve the honeydew produced by phytophagous insects and helps to eliminate the eggs laid on the leaves. It is advisable not to carry out treatments too frequently, as it can encourage the emergence of Neofabraea spp.
• Remove mummies (dried fruit) from the orchard as they cause a high risk of infection.