Tesseratus scale

Systematic position: Duplaspidiotus tesseratus belongs to the order Hemiptera and the family Diaspididae (armored scale insects). This insect is a specialized feeder that spends most of its life cycle attached to the bark, leaves, or fruits of the host plant.

Host plants: The primary hosts for this species are citrus trees, including lemons, oranges, and mandarins. It is also documented on various tropical and ornamental plants, often causing economic damage in plantations and greenhouse environments.

Biology and life cycle: The life cycle consists of the egg stage, the active crawler stage (the only mobile phase), and the sedentary adult stage. Females secrete a tough, protective scale (test) over their bodies, which protects them from environmental stressors and many external threats.

Damage and severity: Damage is caused by both adults and nymphs extracting sap from the plant. Heavy infestations result in yellowing of the foliage, leaf drop, poor fruit quality, and stunted plant growth. In severe cases, the affected twigs or branches may die due to the loss of nutrients.

Protection measures: Managing Duplaspidiotus tesseratus is challenging due to the protective scale covering. Recommended strategies include:

• Application of systemic insecticides to target feeding stages.
• Using horticultural oils to smother the insects and disrupt their respiration.
• Biological control through the introduction of specific parasitoid wasps or predators.
• Strict phytosanitary inspections of imported nursery stock to prevent spread.