Hemispherical scale

Systematic position. The Hemispherical scale (Saissetia coffeae) belongs to the order Hemiptera and the family Coccidae. It is a significant agricultural and ornamental pest that is distributed globally, particularly prevalent in warm climates and indoor greenhouse environments.

Host plants. This insect is a highly polyphagous species capable of feeding on a wide variety of hosts. Common targets include coffee plants, citrus, ferns, palms, orchids, and numerous greenhouse ornamentals. The insects are typically found on the undersides of leaves, along the main veins, and on young stems.

Biology and life cycle. The species undergoes incomplete metamorphosis. The adult female is characterized by a distinctive, glossy, brown, hemispherical shield that protects her body. Reproduction is commonly parthenogenetic, with a single female capable of producing hundreds of eggs. Upon hatching, the mobile nymphs, known as crawlers, move across the plant surfaces to find ideal feeding sites where they settle and develop their shields.

Damage and severity. The primary damage is caused by the direct extraction of sap, which leads to stunted plant growth, leaf chlorosis, and potential leaf drop. Furthermore, the excretion of honeydew promotes the growth of sooty mold (Capnodium spp.), which covers the leaves in a black, powdery film. This interferes with photosynthesis and significantly reduces the plant's aesthetic value and overall vigor.

Control measures. Controlling Saissetia coffeae requires a combination of strategies because the hard scale provides protection against many contact insecticides.

• Application of systemic insecticides that circulate within the plant sap.
• Physical removal of infested leaves and stems.
• Quarantine protocols for new plants entering a collection.
• Monitoring for the emergence of crawlers, which are the most susceptible life stage.
• Maintaining optimal plant health to enhance resistance against infestations.