MANGO is an important foreign currency earning fruit crop. It is relished and liked by all due to its flavour, and dietary and medicinal importance. Mango is nutritionally rich in carbohydrates and vitamin A and C. Young, green, immature fruit is an effective antidote for mild sunstroke.

Mango suffers from a number of diseases which affect different parts of plants at all stages of development. The Quick decline’ or ‘Sudden death’ or ‘Tree mortality’ is a newly emerged problem.

Scientists are busy in discovering the cause and measures for controlling it. However, growers do not agree with them. Anthracnose (Glomerella cingulata-Colletotrichum gloeosporioides), powdery mildew (Oidium mangiferae), sooty mould (Capnodium romasum), fruit rot (Aspergillus niger), leaf blight (Pestaloptiopsis mangiferae) and stem blight (Diplodia spp.) are some old and known fungal diseases of mango in Pakistan. But, no information regarding the extent of damage to the plants is available.

The powdery mildew caused by Oidium mangiferae Bert is one of the known diseases remains most destructive in most of the growing countries, including India, Ceylon, South Africa, Brazil, Australia and the US, as well as all mango growing areas of Pakistan.

In Pakistan, the powdery mildew appears from January to March. The disease is characterized by superficial whitish gray mycelial growth, initially appearing on flowers and buds (inflorescence). Later the fungus spreads to fruit, leaves, shoots and trunk. The whole surface of the affected flowers and young fruit gets covered with a powdery substance consisting of millions of spores called conidia.

When these spores become mature, they blow away by even mild winds from the affected portions to the healthy one and produce fresh infections in neighbouring trees or in nearby orchards.

A few affected flowers may cause a widespread epidemic under favourable climatic conditions. Infected flowers fail to open and sometimes shed before fertilization and result in substantial reduction of fruits. Delayed infection of the disease affects the fruit development and large numbers of them drop prematurely.

The period of low rainfall and moderate temperatures favour the development of powdery mildew causing fungus. Its maximum germination occurs between 14-24OC. High nitrogen levels produce succulent and rapidly growing tissues which are attacked by the fungus and also increase mildew severity. Plants growing in the shade also have severe mildew. Reduced light favours infection and fungus growth. These problematic conditions are common in mango growing areas.

Powdery mildew is provided the most favourable etiological conditions as well as high use of nitrogen fertilizer and small space between trees and rows. Therefore, alarming risk of epidemic outbreak remains constant.

In the light of these facts, preventive and curative measures for the control of disease must be applied, e.g. to avoid high doses of nitrogen fertilizers. Proper sanitation of orchards and pruning of trees may also help reduce the infection and growth of the disease-causing fungus.

Spray of suitable fungicide at an interval of 10-15 days should be done when the inflorescence starts appearing. If disease appears in epidemic form, the plant should be re-sprayed. While spraying on the flowers, due care should be taken, not to hit the flowers directly. The fungicide should be used alone and in proper dose.

With special reference to the Quick decline’ or ‘Sudden death’ or ‘Tree mortality’ disease of mango, Khuhro et al. (2004) suggested that the integrated pest and disease management practices must be applied by using different insecticides in combination with suitable fungicides, whereas different cultural practices may also help check the problem. They recommended the following:

1. Keep trees healthy and avoid unnecessary stress (drought, injury, nutrition, etc.).

2. As the infested tree plants survive and often can recover with age, therefore large spacing in nurseries and orchards helps in slowing the spread from plant to plant.

3. Only healthy seeds, seedlings and plants should be used for planting and budding or grafting.

4. Inter-cropping, mix cropping, cover cropping and multiple cropping in or in the surrounding of mango orchards must be avoided so that the similar possible pathogens of the sown crop and mango (both) may not be multiplied and spread in orchards.

5. Irrigation must be applied as per requirement but not subject to the availability.

6. Avoid high doses of nitrogen fertilizers, but apply proper and balanced fertilizers on the basis of soil type, age and need of the tree.

7. Proper sanitation of orchards and pruning of trees (eradication of disease causing organisms through removing and burning of diseased plants or plant parts) help reduce the infection and growth, development and further spread of beetle and the fungi causing disease complex situation.

Therefore, heavily infested plants or plant parts should be removed and destroyed. Once attacked tree becomes more attractive to female beetles, therefore infested trees must be removed and burned before completing the lifecycle of beetles that requires 55 days. Hence it is ensured that the attacked trees should not be a source of beetles.

8. Easily available broad-spectrum insecticides in combination with the fungicides should be used when all other ways fail. Proper application method with optimum dose must be confirmed. However, encouraging results could be obtained by consulting with the entomologist and pathologist.