Glover scale

Systematic position. The Glover scale (Lepidosaphes gloverii) is a member of the order Hemiptera and the family Diaspididae. It is a highly specialized armored scale insect that causes significant economic damage to citrus industries worldwide by draining the sap of host plants.

Host crops. This pest primarily attacks citrus trees, including oranges, lemons, mandarins, and grapefruits. While native to subtropical regions, it can thrive in greenhouses or indoor environments, making it a critical threat to nursery stock and ornamental citrus trees.

Biology and lifecycle. The lifecycle consists of eggs, mobile crawlers (first-instar nymphs), and sessile adults. Females develop a long, narrow, dark brown protective scale. They reproduce sexually, and in warm climates, multiple overlapping generations occur annually, allowing the population to build up rapidly if left unchecked.

Nature of damage. The insects congregate on leaves, twigs, and fruit. Their feeding causes localized yellowing, leaf drop, and bark splitting. On fruit, the presence of these scales creates unsightly blemishes, which significantly lowers the commercial value and marketability of the harvest.

Control measures. Effective management requires an integrated approach.

• Regular field scouting to identify the crawler stage.
• Targeted applications of contact and systemic insecticides during peak crawler activity.
• Utilization of horticultural oils to smother the insects under their scales.
• Implementation of strict quarantine protocols for imported plant material.