This fungal disease (Nectria cinnabarina) can attack most woody plants, entering its host through dead bark or the air pores of living bark on weakened plants. Specimen trees and established shrubs are therefore considerably more at risk than hedges where it is a rare visitor…
As pathogens go, Coral Spot is not particularly strong which is why it can only take a hold once a plant has been weakened by other diseases or environmental factors. Therefore, if it does appear, it is worth checking nearby plants to see if any precursor (including something as simple as frost damage / under or over watering) has affected these plants as well.
And talking of appearance, the small coral-pink spots (pustules) that give the fungus its name only appear on wood after it has died – indeed, a dead branch will be the first visible indication that something is amiss.
Acer, Beech, Hornbeam, Horse Chestnut, Lime and Walnut trees.
Prevention and Cure
• It is best to prune trees in dry weather – especially if you have any of the most susceptible species listed above
• When pruning, cut through the collar (the swollen end of a branch where it meets the trunk) as this area heals the fastest
• Cut out infected branches immediately they are seen (right back to healthy wood) and burn or carefully dispose the debris. Do not leave any diseased wood lying about the garden or chip or compost it. Remember, the fungus will carry on living on a removed branch and the pustules will spore if not destroyed
• There are no fungicides specific to Coral Spot
• Coral Spot is active throughout the year