RESUMEN
Scab (Venturia inaequalis) is the principal disease endangering both integrated and organic apple production. Scab pressure tends to build up over the years and organic farmers rely mainly on copper and sulphur treatments for control. The use of Cu in crop protection received scrutiny in recent years as this metal tends to accumulate in soil and substrates. A number of alternative organic control substances have been proposed, with variable success in scab control. We investigated the effect of these alternative organic scab control measures on several apple varieties with low scab susceptibility. The choice of scab treatments had important effects on the mineral composition of leaves and fruits. As these values affect current and future yield in perennial crops, as well as storage quality, the use of certain scab control agents requires corrective application of nutrients during and in-between growth seasons.