Phytophthora root rot is characterized by beads of sap found on the tree trunk. Cracking may also occur on the trunk. Fruit may be partially covered with brown spots.
Solutions
The key factor in reducing the threat of root and crown rot is good water management. Good soil drainage is best provided before planting. Plant on mounds made by working up the soil. Never cover the graft union with soil and do not water the crown area directly. If you suspect crown rot, carefully cut away affected bark at the soil line. Trees can sometimes be saved by removing soil from the base of the tree down to the tops of the main roots and allowing the crown tissue to dry out. Tolerant rootstocks may help prevent infection.
For more information, see the Phytophthora Root and Crown Rot Pest Note.