Coconut pests & diseases

What is the difference between a pest and a disease and why does it matter?

Sometimes it is difficult to tell whether a plant problem is caused by a pest or disease. A pest is a destructive insect or other animal that attacks crops (or bothers people in other ways). Pests of coconut include Coconut rhinoceros beetle and red palm weevil (both insects) or rats (mammals).

A disease is a problem affecting the structure or function of the plant, and are typically caused by small organisms like bacteria or viruses or fungi. Diseases affecting coconut include Cadang-cadang (a virus), and Aspergillus mould (a fungus).

Sometimes pests can also cause diseases indirectly. For example, an insect might be a host of a bacterium. The insect is not affected by the disease, but it helps transfer the disease from one plant to another. Bogia Coconut Syndrome (BCS) is an example, which is caused by a Phytoplasma bacterium transferred between palms by sap-feeding insects.

Although physical injury does not directly cause disease, it can provide a way for a disease to infect the plant, or it can weaken the plant's natural immunity.

It is important to know what type of organism is the cause (pest insect or other animal, bacterium, fungus or virus) to know how to treat the problem. For example, Ganoderma fungal infection may be mistaken for lethal yellowing of palms or Bogia Coconut syndrome (BCS) caused by Phytoplasma bacteria. Ganoderma and Phytoplasma require different methods of treatment. Therefore, misdiagnosis of Ganoderma as lethal yellowing or Bogia by Phytoplasma may lead to the movement of infected palms and spread of the fungal spores. Also, poor nutrition can cause yellowing of palms. The cause of palm yellowing has to be identified so that the correct treatment can be applied. 

Sometimes pests and diseases only occur from time to time as 'outbreaks'. Outbreaks can be devastating to the coconut crop. These outbreaks can be caused by changes in the environment. For example, after a cyclone, which can create new resources for a pest (such as dead standing palms or decaying vegetation), destroy natural enemies of pests, or decrease the natural immunity of the palm, making it more likely to be affected by diseases (such as viruses and bacteria).

Information on pests and diseases

The focus of this section is on the pests and diseases that have the potential to cause the most damage in the Pacific: more detailed information is given for pests and diseases that commonly cause severe problems. Information is organised alphabetically according to the common name of the pest or disease.

For each disease listed below (and in the menu drop-down list), information is provided about Life-cycle and identification, Symptoms, Impacts, Distribution, Prevention, Controlling the pest/disease, together with Information sources and further reading. These pages include information from PestNet, Plant Village and many other sources.

If you have a palm that looks unhealthy, you can use the Identification section of the website to use the symptoms to find out what the problem might be.

The Prevention section of the website has general information on how avoid spreading pests and diseases (biosecurity). 

Ants   Aspergillus mould
Bogia coconut syndrome   Cadang-cadang disease
Coconut bug   Coconut flat moth
Coconut foliar decay   Coconut hispine beetle
Coconut leaf miner   Coconut mite
Coconut rhinoceros beetle - Oryctes rhinoceros   Coconut scale & false scale
Coconut sexava treehopper   Coconut spike moth
Coconut termite   Finschhafen disorder
Ganoderma butt rot   Lethal yellowing
Mealybug - cacao   Mealybug - pineapple
Mealybug - striped   Melanesian coconut rhinoceros beetle
Palm weevil   Rats
Red palm mite   Red-ring disease

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PestNet information sheets

A number of other pests and diseases can also affect coconut, but these are usually less severe, or more localised. Information on these can be found at PestNet, in the fact sheets section of their website. The links below take you directly to a copy of the PestNet PDF information stored within the toolkit, as well as an web version on PestNet, indicated by: [ONLINE].

Coconut thread blight [ONLINE]   Coconut leaf stripe [ONLINE]
Coconut embryo rot [ONLINE]   Coconut mealybug [ONLINE]
Coconut seedling basal stem break [ONLINE]   Coconut seedling blight [ONLINE]
Coconut leaf spots [ONLINE]   Coconut bud rot [ONLINE]
Coconut spathe bug [ONLINE]   Coconut false smut [ONLINE]
Coconut stick insect [ONLINE]   Cassava Amblypelta dieback [ONLINE]
Sugarcane weevil borer [ONLINE]   Coconut seedling basal stem break [ONLINE]

The Pacific Pests and Pathogens app for mobile devices also contains a wealth of information, including information on coconut pests and diseases.

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