Orange spots on an apple tree: just unsightly, or something to address?

Your apple tree has apple rust. The round orange-yellow leaf spots are typical, and nearby junipers fit the infection cycle well: the fungus alternates between juniper and apple.

This late in the season in Norrmalm, Sweden, treating the leaves is rarely worthwhile. Remove the worst affected leaves if practical, but above all collect fallen leaves so that the tree goes into autumn as cleanly as possible. Apple rust often looks worse than it is on an otherwise healthy tree, although repeated severe attacks can weaken it.

The main steps now and in spring

• Check nearby junipers for swellings or jelly-like orange growths, especially in a damp spring. That is where infection usually comes from.
• If an infected juniper is very close to the apple tree, remove affected branches or consider removing the shrub if attacks recur year after year.
• Open up the crown at the next pruning so that leaves dry more quickly after rain.
• If you choose to use a treatment, it would need to be applied preventively next spring rather than now, when spots are already present. Always follow the label for fruit trees.