Apple scab (Venturia inaequalis): Preventive measures in organic pome fruit production (Biofruitnet Practice Abstract)

Applying a combination of preventive, protective and curative measures during the ascospores phase in spring efficiently decreases the risk of infection. Practical recommendations Preventive measures to avoid risk of infection: • Varieties: Use scab-resistant/tolerant apple varieties, such as e.g. Story/Inored, Topaz, Opal, Ladina, or Santana • Good plant aeration/site selection: Apple scab depends on leaf moisture for successful infection. There-fore, it is important to allow quick drying of the plants with well-lit and air-permeable canopies and planting systems. To do so: • Align rows towards the main wind direction; • Space plants widely; • Prune trees and roots to achieve steady growth and a loose canopy. Preventive measures to reduce inoculum and reduce the risk of infection: Promotion of foliage decomposition in autumn/spring reduces the ascospores potential for the upcoming season. You can promote this via: • Mechanical shredding of infected plant parts (fallen leaves) by tillage; • Use of Vinasse in autumn at leaf fall (single application); • Use a leaf vacuum cleaner to actively remove infested leaves from the tree strips within the orchard