Treating a sick mango for fungal diseases involves using a fungicide. All susceptible parts of the tree should be thoroughly coated with the fungicide before infection occurs.
If applied when the tree is already infected, the fungicide will have no effect.
Fungicide sprays need to be reapplied on new growth. Apply fungicide in the early spring and again 10-21 days later to protect the panicles of blossoms during development and fruit set. If powdery mildew is in evidence, apply sulfur to prevent the spread of the infection to new growth.
If the tree becomes infected with verticillium wilt, prune out any infected limbs.
Mango scab generally doesn’t need to be treated since an anthracnose spray program also controls scab.
Algal spot will also usually not be an issue when copper fungicides are periodically applied during the summer. To reduce the risk of fungal infections, grow only anthracnose resistant cultivars of mango.
Maintain a consistent and timely program for fungal application and thoroughly cover all susceptible parts of the tree. For assistance with treatment of disease, consult your local extension office for recommended control recommendations.