This fungal disease affects almonds,apricots, nectarine as well as peaches.
Life cycle;
The fungal spores survives on fallen leaves and branches.
In spring these spores become airborne and land on the newly emerging leaf buds.
As the buds open, and the young leaves appear the yeast like fungus feeds on them, and affects their development.
The leaves become distorted and develop bronze-red blisters, these blisters later turn an off white colour.
The resulting smaller leaf size makes them less efficient when photosynthesising.
This weakens the trees general development, which in turn can cause the flowers and fruit to fall off.
In more serious cases this weakenig can kill the tree.
Later in the season, the affected leaves will fall off to be replaced by a second flush leaves.
These leaves are usually unaffected by the fungus.
Control;
Prevention is the best option and there are a few ways this can be achieved.
Remove infected leaves, flowers and fruit as soon as they are seen.
Subject to the size of the trees,cover them in a polythene tent arrangement in January/Februry before any over-wintered spores become airbourne.
Failing that; spray the whole tree with Bordeaux mixture in autumn at leaf fall, then as the buds swell in late January and repeat two weeks later to kill the fungus before the leaves emerge from the buds.
Clear up infected, fallen leaves around trees and destroy them, do not compost them.
Keeping the tree healthy during the growing season will make it less susceptible to attack.
Water well in dry summers to prevent stress.
Mulch around the base of trees to conserve moisture.
Avoid overfeeding with nitrogen fertiliser.