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Source: Avas [summ. Mod.DHA, edited]

5000 trees have been brought to the Maldives to address coconut shortages due to diseased palms. The palm trees are currently under quarantine. All will be checked for any diseases before being distributed to different islands across the country, the Agriculture Ministry said.

Experts believe the palm trees in the Maldives are suffering from sooty mould, a fungal disease that grows on plants and other surfaces covered by honeydew created by certain insects. Public awareness should be raised on diseases affecting the trees and measures to eradicate them.

Communicated by:

[Sooty moulds include a range of fungal species from genera such as _Alternaria_, _Capnodium_, _Cladosporium_, _Fumago_, and _Scorias_ which live as saprophytes on the host's surfaces. They are not pathogens in the true sense but secondary parasites that do not invade plant tissue. The moulds follow different pests (for example, scale insects, aphids, mealy bugs) excreting honeydew that coats plant surfaces and provides a growth substrate for the fungi. The fungi occur on a wide range of hosts including many crop trees, shrubs, and ornamentals. Sooty moulds are generally more likely to occur in dry conditions as rain washes the honeydew substrate away.

Plants become blackened with velvety fungal growth reminiscent of soot and are usually sticky. The whole plant may be affected, the moulds are difficult to remove. The insects producing the honeydew may or may not be pests of the host in themselves. Independently, the sooty covering as such reduces plant vigour and productivity by restricting the light available to the host for photosynthesis. The moulds may also grow on plants not affected by insects if honeydew drips from overhanging vegetation. Disease management mainly focuses on control of the insects and may involve pesticides, detergents, or oil-based organic sprays, as well as biological control by specific predator insects.

While the addition of young, disease free coconut palms to the national crop pool of any country can be expected to be beneficial, it will not eliminate the problem in the Maldives described above. With sooty mould indicating an insect problem, not the presence of a plant pathogen, even crop varieties resistant to any potential insect pests or diseases of the palms can be affected by dripping honeydew from other vegetation. It will, therefore, be essential to control insects in and around existing and new coconut plantings as well.

Maldives: and,143
Location of Maldives:

Sooty mould on coconut:,, and
Sooty mould on other hosts: (citrus), (citrus), (black pepper), and (camelia)

Sooty moulds on coconut:
Sooty moulds on various species:,,, and
Fungal taxonomy via:
Information on insects via:
- Mod.DHA]


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