In this section:
Yeast Rots
Cause
Various yeasts
Affected
Most common on apricots, but affects all stone fruit.
Symptoms
Symptoms are confined to the fruit. The rate of growth of yeast rots in infected fruit increases as sugar levels rise during fruit ripening.
When infected apricots are cut in half, flesh surrounding the stone cavity is watery. Fungal growth often appears as a white smearing on and throughout the watery area. These fruit if processed, will turn black during drying.
Skin of infected fruit often remains intact while the flesh loses structure. Fruit with advanced symptoms often hang from the tree like a water filled balloon, sometimes remaining attached to the tree well after harvest.
Condition favouring
Spores that cause these rots are common in orchards. Warm, wet and humid conditions are particularly favourable for disease spread and development.
Control
Control is based on reducing the level of inoculum in the orchard and the number of agents that spread the inoculum. Control of carpophilus beetle can reduce the spread of yeast rots. Carpophilus beetle both injure the fruit allowing infection and carry the spores that cause the rots.
After harvest, fallen fruit should be removed from the orchard if possible, to prevent it being a source of inoculum for later varieties and to prevent it becoming a breeding ground for carpophilus beetle. In cultivated orchards the fruit can be disced in.
At pruning, infected fruit which have remained attached to the tree should be removed from the orchard, as they are a source of infection to next years crop.
