As you enjoy a bountiful mango harvest from your farm and eagerly anticipate the summer profits, there’s a crucial matter that demands your immediate attention.
Did you know that your mangoes are still at risk even after being plucked from the trees? Yes, it is. Post harvest diseases such Anthracnose, Stem End Rot and Aspergillus Rot can pose a threat to your mangoes and potentially affect your earnings by reducing marketability.
Don’t let your profits wipe off! Identify the factors that favour their development, spot the signs early and implement effective control measures to secure your hard-earned success.
Common Post Harvest Diseases affecting Mangoes
Anthracnose is a common fungal disease caused by the fungi Colletotrichum gloeosporioides. It is highly prevalent in regions with frequent rainfall during mango fruit development and maturity. The disease spreads through spores that are dispersed by wind, rain, insects and pruning tools. The spores can enter the mango tree through wounds.
Fruits can become infected at any time when weather conditions are favourable, such as optimal temperatures (20-30°C), high relative humidity, prolonged rainfall or heavy dew.
Symptoms of Anthracnose in Mango
- Anthracnose disease affects leaves, twigs, young flowers and fruits causing blighted foliage, blossom blight, withered tip and fruit rot.
- Anthracnose affected fruits will show dark, irregular sunken lesions or spots on the fruit surface. These lesions may start small and gradually grow larger leading to fruit rot.
- They often have a slightly raised, corky texture.
- The whole fruit may turn black and shrivel under severe infection.
- In some cases, anthracnose infection can lead to gumming or oozing of a dark-colored sap from infected areas on the fruit, leaves, or twigs.
Stem End Rot
Stem end rot is caused by the soil borne fungus Lasiodiplodia theobromae. The disease primarily targets the stem end or pedicel region of the fruit. This disease incidence is favoured by high temperature and rainfall.
Symptoms of Stem End Rot in Mango
- Infected fruits exhibit dark brown to black discoloration at the stem end, spreading towards the upper portion of the fruit.
- The affected area appears sunken or depressed, often surrounded by a water-soaked margin.
- Under humid conditions, these affected areas rapidly expand and within just a couple of days, the entire fruit turns completely black.
- As the disease progresses, an unpleasant odor may be emitted from the decaying fruit.
Aspergillus Rot / Black Mould Rot
Aspergillus rot, also known as black mould rot, is caused by various species of the fungus Aspergillus sp. The fungus primarily infects ripe or overripe fruits, particularly those that have cut surface or wounds or injured during harvesting or handling. The disease development is more prevalent under high temperature (30 – 36°C).
Symptoms of Aspergillus Rot in Mango
- Greenish-black or grayish-green mould growth on the fruit’s surface.
- As the disease progresses, the infected areas become sunken or depressed, often with a soft, decayed texture beneath the mouldy surface.
- Affected fruits may emit a characteristic musty or moldy smell.
- The fungus may produce abundant spores, which form a dusty or powdery black fungal layer on the fruit surface.
Management of Post Harvest Diseases in Mango
- Regularly remove and destroy infected plant debris, fallen fruits and diseased plant material from the orchard.
- Do not harvest immature fruits.
- Harvest the fruits with 10 mm stalk (in case of stem end rot).
- Spray Carbendazim 50% DF (2 gm/lit of water) or Thiophanate methyl 70% WP (0.5 gm/lit of water) or Mancozeb 75% WP (3 – 4 gm/lit of water) at weekly interval during flowering, followed by monthly sprays until harvest. Cease spraying 14 days before harvest.
- During dry weather, flower sprays can be reduced to 2 weeks intervals.
- Spraying Copper oxychloride at 2 g/lit of water can also help control anthracnose. However, avoid using copper oxychloride during flowering.
- Dip the fruit within 24 hours of harvest in hot water at a temperature of 52°C combined with 0.5 – 1 ml of Carbendazim per liter of water. Treat the fruits by fully submerging them for 15 minutes in this dip solution.
- Store the fruits in a well-ventilated place.
- Handle mangoes with care during harvest to minimize physical damage that can provide entry points for fungal infection.
- Avoid long term storage of fruits from the orchards with history of stem rot losses.
(Note: The dipping temperature should not exceed 52°C to avoid skin damage. During wet weather condition, reduce the temperature to 50°C)