A magnified view of Croton Scale. (Image: Ministry of Agriculture)

Barbadian householders and the local agricultural sector have been put on alert that they have another insect pest with which to contend. This time it is the Croton Scale, scientifically known as Phalacrococcus howertoni, which has been detected on crotons and acalypha in the parish of St. James.

This was revealed today by Government Entomologist, Ian Gibbs, who said that the insect was positively identified yesterday by Dr Greg Hodges of the Florida Department of Agriculture and Consumer Services.

Mr. Gibbs explained that "the croton scale is a member of the soft scales (Coccidae) family of insects which attack a wide range of plants. It has been found on 72 plant species in Florida. Included in these are the soursop, carambola, fat pork, sea grape, mango, avocado, guava and plums, all commonly found in Barbados. It also attacks ornamental plants such as heliconias, crotons and acalypha."

"Adult females and late growth stages (instars) have a greenish yellow appearance with dark marks, and are approximately 3.5 mm to 7.0 mm long and 2.0 mm wide."

The Ministry of Agriculture Entomologist further pointed out that "the eggs hatch into mobile crawlers which search for suitable sites on the host plant on which to settle and feed. They suck sap from the plant and remain at these selected sites for the rest of their life cycle. Scale insects suck copious amounts of sap from the host plants and also excrete viscous liquid called ???honeydew’ that contains a lot of sugars. When this honeydew spreads out on the leaf surface it provides an ideal layer in which fungi can grow."

He said "a complex of fungi usually grows in this layer and produces the characteristic black sooty mould, which Barbadians often call ???blight’. This sooty mould will also reduce the photosynthetic capability of the plant."

The effects of the sap removal by the scale insect and the formation of the sooty mould layer on the leaves often combine to weaken the plant, make it less productive, and, in the case of ornamentals, make them less attractive or not saleable.

Mr. Gibbs said the croton scale insect could be controlled by the application of conventional systemic insecticides such as Aval?? (acetamiprid), Actara?? (thiamethoxam), Merit?? (imidaclorprid) or Orthene?? (acephate, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, ‘, NULL, NULL, 0); or by using or organic alternatives like Safer Soap?? (potassium salts of fatty acids), Organocide?? (fish oil) or Ultrafine Oil?? (paraffin oil).

He said the Ministry of Agriculture was monitoring the situation in the St. James area, as well as neighbouring parishes in an effort to not only minimize its presence but also to quickly control it.

Persons who detect this insect should contact the Entomology Section of the Ministry of Agriculture at 434-5103 (Ian Gibbs) or 310-2821 (Bret Taylor).

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