Main cause: Phytophthora cinnamomi; encouraged by waterlogged soil

Solution: Improve drainage, avoid overwatering, use healthy nursery plants, and apply locally approved treatments where appropriate. Severely affected trees may be difficult to save.

Main cause: Fungus, commonly Colletotrichum species

Solution: Remove infected and fallen fruit, prune dead twigs, improve airflow, handle fruit carefully, and use an approved fungicide if needed. 

Main cause: Fungus, Sphaceloma perseae 

Solution: Remove infected debris, maintain good airflow, and use a locally approved fungicide according to its label when necessary.

Main cause: Fungus, Pseudocercospora purpurea 

Solution: Prune to improve airflow, remove infected debris, avoid prolonged leaf wetness, and use an approved fungicide if warranted.