Green scale

Systematic position: The Green scale (Coccus viridis) belongs to the order Hemiptera and the family Coccidae. It is a significant agricultural pest widely distributed across tropical and subtropical regions worldwide, also acting as a common pest in indoor plant collections and greenhouses.

Host plants: The insect is a broad polyphagous feeder. It is particularly known for causing severe economic damage to coffee plantations and various citrus species. Additionally, it frequently infests ornamental plants, including gardenias, ixoras, ferns, and various orchids, typically colonizing the undersides of leaves along the midribs.

Biology and life cycle: Reproduction occurs primarily through parthenogenesis, meaning females do not require fertilization to lay eggs. The female produces eggs that are protected beneath her flat, translucent, pale-green body. After hatching, the crawlers are mobile and disperse across the host plant before settling permanently to feed on the plant's vascular tissues.

Damage and severity: As a sap-sucking insect, Coccus viridis removes essential nutrients from the plant. A hallmark of infestation is the excretion of honeydew, which promotes the growth of sooty mold. This layer of black fungus inhibits photosynthesis, causes leaf chlorosis, leads to premature leaf drop, and can result in the death of young shoots or even the entire plant if left untreated.

Control measures: Integrated Pest Management (IPM) is crucial for controlling Green scale.

• Application of systemic insecticides that are absorbed by the plant.
• Biological control using parasitoid wasps (e.g., Cephalosporium lecanii or Metaphycus species).
• Pruning and removing heavily infested branches.
• Maintaining plant vigor through balanced fertilization and correct watering practices.
• Routine inspection of imported plant material to prevent new introductions.