Symptoms

• In its early stages, Phytophthora leaf blight occurs as small dark brown or purple lesions with an amber ooze in the center.
• Older lesions are zonate with white fuzz of sporangia on the outer edge.

Management

• Hot Water Disinfestations
• Fallows for Disease Suppression.
• Isolate plantings (e.g., three small, separate patches instead of one large patch).
•  Prepare the soil well and amend it before planting if calcium, magnesium, or phosphorus are needed.
•  Monitor plant calcium levels by leaf analysis, and maintain calcium at recommended concentrations to prevent development of Pythium corm rot.
• Add lime material before planting to raise soil pH to 6.0-6.8.
• Rotate taro with other crops.
• Incorporate compost and apply surface mulch.
• Rogue (kill and remove) diseased plants, taking them far from the planting area and destroying them by burying, burning (if allowed), or composting