Plantwise Factsheets for Farmers
Alternaria on Mango
Recognize the problem
The fungus (germ) causes black spots and post harvest fruit rot during storage.
The germ infects the fruit during growing stage and becomes inactive. When fruit is harvested and as the fruit continues to ripen, the germ resumes growth resulting in an active rot.
The rot spreads, softens and sinks into the flesh of the fruit.
The germ hides in the soil and may be picked up by branches that hang down touching the soil. The infected material such as infected old leaves or mature fruits may keep the germ in the soil.
- Prune back the tree to prevent branches from touching the soil.
- Collect and destroy fallen fruits.
- Remove dead branches, twigs and dead leaves from the mango orchard.
- Postharvest hot water treatments have also shown to be effective against Alternaria damage. Harvested fruits can be sprayed, brushed or dipped for 5 minutes in hot water (60°C).
- If spraying is possible in your orchard, use fungicides such as Famoxadone + cymoxanil or mancozeb. This should be done 2-3 weeks after fruit set.
- Once harvested, the mature green mangoes can be dipped in a mixture of water at 50°C, mancozeb (3g of active ingredient per litre of water) and Iprodione (0.5g of active ingredient per litre of water).
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
The recommendations in this factsheet are relevant to many countries where this pest or problem is present
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