African scale

Taxonomic position. The African scale (Lecanodiaspis africana) belongs to the order Hemiptera and the family Lecanodiaspididae. This sap-sucking pest is characterized by a sedentary lifestyle, with the female residing under a protective waxy test, which serves as a biological barrier against predators and many conventional contact pesticides.

Host plants. This species is a polyphagous pest capable of infesting a wide range of woody plants, shrubs, and ornamental species. Its host range includes various fruit trees and landscape plants, making it a significant concern for both agricultural producers and homeowners who maintain diverse garden environments.

Biology and life cycle. The life cycle involves a nymphal stage known as the "crawler," which is the only mobile phase of the insect. Crawlers emerge from under the mother's shell and migrate to suitable sites on stems or branches. Once settled, they insert their mouthparts into the plant tissue to extract sap, initiate the development of their protective covering, and transition into stationary feeding.

Type of damage and economic impact. The primary damage is caused by the depletion of plant nutrients, leading to stunted growth, wilting, and twig dieback. Furthermore, these scales excrete honeydew, which fosters the growth of sooty mold. This mold covers the surface of leaves and fruit, blocking sunlight, inhibiting photosynthesis, and significantly reducing the aesthetic value and marketability of the produce.

Control measures. Managing Lecanodiaspis africana requires a multifaceted strategy:

• Applying horticultural oils during the dormant season to suffocate overwintering stages.
• Targeting the crawler stage with systemic insecticides to interrupt the life cycle effectively.
• Pruning and destroying heavily infested branches to reduce the pest population density.
• Maintaining healthy plant vigor through balanced irrigation and fertilization to minimize the impact of infestations.