Plant Health


The Pacific’s fragile ecosystem is constantly at risk from invasive species, pests and diseases. It is therefore vital that sustainable and appropriate management practices are developed and utilized to ensure   sustained productive use of the land. Plant Health aims to promote these practices by utilizing its three main units, entomology, pathology and weeds in undertaking regular surveys of pests and diseases, providing information, creating awareness among farmers,  updating information databases and assisting in eradication activities. 
 

Coconut scale insects. (CSI). (Aspidiotus destructus)
Friday, 23 April 2010 10:16
Coconut scale insect pests are common in coconuts as its name suggests but in severe infestation could spread to perennial fruit trees. Damages to leaves, stalks and branches cause stunt growth, defoliation and dieback. Damages to fruits cause blemishes, deformed and unmarketable. Coconut scale insects are recorded in both sub tropical and tropical regions and is usually present in all countries where coconut trees are present. It is also known as armored scale, transparent scale, bourbon scale, bourbon aspidiotus and is sometimes called red flies because of the abundance of male flies in severe outbreaks. CSI is present in most of the Pacific Island countries particularly the atoll countries; Tuvalu and Kiribati.

Host range

CSI host are typically perennial species such as; avocado, breadfruit, mango, guava and papaya. However, coconut is the preferred host and they are found mainly on the underside of the leaflets. In severe cases, CSI infestation are seen all over the entire plant.

Damage symptoms

Scales feed by sucking sap from the plant cells whilst secreting toxins from their salivary glands in the process. Continuous feeding causes drying up of leaflets giving a yellow colour initially then turning brown in advance cases  eventually killing the plant by total cessation of the photosynthesis process.

Ecology

CSI life cycle lasts 32-35 days. The larvae (crawlers) and adult males are the mobile stages of the scale. The female lays 20-50 eggs over a period of few days and hatches into crawlers in 7-8days. Crawlers  (both sexes are mobile) colonize the plant and feed using feeding tubes inserted into the cells. Females have two nymph stages while the male have four, two larval stages, pre-pupa and pupa stages respectively. The scale cover of adult female is oval in shape, flat, thin and translucent. Males have a pair of wings and is motile.

Control

Biological control using Telsimia nitita is recommended for atoll conditions as well as volcanic islands. For outbreaks in volcanic islands, insecticides can be used to quickly reduce the population to a manageable level then followed by the release of Telsimia nitida. Insecticides are not recommended for atolls.

 

 

PPS Pest Advisory Leaflet (PAL) #38, December, 2004.




Coconut scale insects. (CSI). (Aspidiotus destructus)

Coconut scale insects is precorded in both sub tropical and tropical regions and usually present in all countries where coconut trees are present. It is also known as armored scale, transparent scale, bourbon scale, bourbon aspidiotus and sometimes called red flies because abundance of male flies in severe outbreaks. CSI is present in most of the Pacific Island countries particularly the atoll countries; Tuvalu and Kiribati.

Host range

CSI host are typically perennial speciaies such as; avocado, breadfruit, mango, guava and papaya. However, coconut is preferred host and found mainly on the underside of the leaflets. In severe cases, CSI infestation are seen all over the entire plant.

Damage symptoms

Scales feed by suck sap from the plant cells whilst secreting toxins from their salivary glands in the process. Continues feeding caused drying up of leaflets giving a yellow colour initially then turn brown in advance cases which eventually killing the plant by total cessation of photosynthesis process.

Ecology

CSI life cycle lasts 32-35 days. The larvae (crawlers) and adult males are the mobile stages of the scale. The female lays 20-50 eggs over a period of few days and hatches into crawlers in 7-8days. Crawlers (both sexes are mobile) colonizes the plant and feed using feeding tubes inserted into the cells. Females have two nymph stages while the male have four, two larval stages, pre-pupa and pupa stages respectively. The scale cover of adult female is oval in shape, flat, thin and translucent. Male has a pair of wings and is motile.

Control

Biological control using Telsimia nitita is recommended for atoll conditions as well as volcanic islands. Outbreaks in volcanic islands, insecticides could be used to quickly reduce the population to a manageable level then followed by the release of Telsimia nitida. Insecticides are not recommended for atolls.

 

Effective management can help maintain productivity of land resources,stregthen food security, safeguard the environment and increase revenue. Plant Health strives to improve awareness on environmental implications of agricultural practices and offering safer environmentally friendly options.