The most important Mango Diseases

Common Diseases Affecting Mango

Throughout its lifespan, mango can suffer from numerous diseases that affect plant parts such as the trunk, branches, twigs, leaves, petioles, flowers, and fruits. These diseases are caused by several pathogens, including fungi, bacteria, and algae, resulting in rot, dieback, anthracnose, scab, necrosis, blotch, spots, mildew, and others. Certain diseases like powdery mildew are especially important for mango production since they are responsible for significant economic losses.

Some of the major mango diseases are listed below.

Powdery mildew (Oidium mangiferae)

Powdery mildew is one of the most important diseases of mango that can affect almost all mango varieties in Kenya. The disease is reported to cause approximately 20% crop loss. Sometimes, as high as 70-80% crop loss has been recorded on an individual plant basis. It may persist for a longer period at 600-1200 meters in many African countries.

A common indication of the disease is the appearance of a white, powdery fungal growth on the leaves, panicle stalks, flowers, and young fruits. The fungus attacks the young tissues of all sections of the inflorescence, leaves, and fruits. This disease can cause flowers and fruits to fall off prematurely, substantially decreasing crop yields or even preventing fruit formation altogether. The spread of the disease is facilitated by rainfall or mist combined with cooler nighttime temperatures during the flowering stage.

Chemical Control Powdery mildew in Mango:

Applying 3 sprays of fungicides at 15 days intervals is recommended for effective control of the disease: Wettable sulphur 0.2% (2 g Sulfex / lit. water). Tridemorph. Dinocap 0.1 per cent

Anthracnose (Colletotrichum sp)

Anthracnose is prevalent and can cause substantial damage to young shoots, flowers, and fruits, particularly in areas with high humidity, frequent rainfall, and temperatures between 24-32°C. The disease can also affect stored fruits. The symptoms of the disease include leaf spots, flower blight, withered tips, twig blight, and fruit rot. The fungus can easily infect tender shoots and foliage, ultimately leading to the dieback of young branches. Older twigs may also be affected through wounds, which can be fatal in severe cases.

Blossom blight severity can range from mild to severe, depending on the prevailing weather conditions. Black spots develop on panicles and fruits, and severe infections can destroy the entire inflorescence, resulting in no fruit set. Infected young fruits develop black spots, wither, and fall off, while mature infected fruits can carry the fungus into storage and cause significant losses during transportation. The fungus can persist on twigs and leaves of mango or other hosts, and the diseased twigs should be pruned and burned along with fallen leaves to reduce inoculum potential. Trees can be sprayed twice with Bavistin (0.1%) at a 15-day interval during flowering to control blossom infection. Copper-based fungicides (0.3%) are recommended for controlling the foliar infection.

Dieback (Botryodiplodia theobromae): 

Dieback is a severe disease that affects mango trees and is prevalent in most growing areas. The symptoms of the disease can be observed at any time of the year but are most noticeable during flowering. The disease causes twigs and branches to dry up, leading to complete defoliation and giving the tree a scorched appearance. The first visible symptom is the discolouration and darkening of the bark, which advances and causes young green twigs to wither, starting at the base and extending outward along the veins of leaf edges. The infected leaves turn brown, and their margins roll upwards. At this stage, the twig or branch dies, shrivels, and falls off, which may be accompanied by gum exudation. In old branches, brown streaking of the vascular tissue can be observed upon splitting them longitudinally. The areas of the cambium and phloem show brown discolouration, and a yellow gum-like substance is found in some of the cells.

Control: 

1. Prune the diseased twigs and spray with copper oxychloride (green copper) on infected trees. Pruning should be done so that the twigs are removed 2-3 inches below the affected portion.
2. In small plants, the pruning of twigs is followed by the pasting of copper oxychloride.

Other major diseases that can infect mango trees and trouble the farmers are the: Phoma blight (Phoma glomerata), Bacterial canker (Xanthomonas campestris), Red rust (Cephaleuros virescens), Sooty mould (Meliola mangiferae), etc.

Some Recommended Diseases Control Products in Mango

The information in this section is provided for educational purposes only. The reader is urged to exercise caution in making purchases or evaluating product information.

Label registrations can change at any time. Thus the recommendations may become invalid. The user must read carefully the entire, most recent label and follow all directions and restrictions. Purchase only enough pesticide for the current growing season.

Post-Harvest Diseases: 

Even during storage, after harvest, the mango fruit is susceptible to many post-harvest diseases like stem end rot (L. theobromae), anthracnose (C. gloeosporioides) and aspergillus rot. Many farmers apply sprays with fungicides to control these diseases and decrease post-harvest losses (field application may also decrease the problem). The following treatments are suggested.

1. Three sprays of carbendazim at 15 days interval should be done in such a way that the last spray is done 15 days before harvest.
2. Post-harvest dip treatment of fruits in carbendazim in hot water at 52+1 °C for 15 minutes.

References

Find more information in the book: “Success in Agribusiness: Growing Mango successfully” written by James Mwangi Ndiritu

Codex Alimentarius Commission. General Principles of Food Hygiene CXC 1-1969. 2021.

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Nutritional Value and Health Benefits of Mango

Mango Tree Information and Variety Selection

Mango tree Propagation

How to cultivate mangos for profit – Mango production – An overview

Planning and Planting a Mango Orchard

Mango Water Requirements and Irrigation Systems

Mango tree Fertilization

Most Common Pests Affecting Mangoes

The most important Mango Diseases

Mango: Yield, Harvest and Post-Harvest Handling