Asterolecanium repugnans

Asterolecanium repugnans is a scale insect belonging to the Asterolecaniidae family within the order Hemiptera. These insects are classified as pit scales because their feeding activity often causes the host plant to form a depression or gall in the bark, providing the insect with physical protection during its sedentary phase.

The pest primarily infests a variety of woody plants and shrubs. It is commonly found on the bark of trunks and branches, where the insects insert their stylets into the plant tissues to feed on phloem sap. Due to their small size and cryptic coloration, they can remain unnoticed for long periods until the damage becomes severe.

The life cycle involves the development of eggs under the female's protective test. Upon hatching, the mobile nymphs, or "crawlers," emerge from beneath the scale to move across the bark. This stage is the most critical for dispersal and the only phase where the insect is significantly vulnerable to contact pesticides.

Feeding results in general loss of vigor, canopy thinning, and localized necrosis of the bark. In severe infestations, the insects can cause twig dieback and render the host plant susceptible to pathogens or environmental stress. The continuous extraction of sap drastically reduces the plant's ability to store energy for growth.

Effective management strategies include integrated pest management (IPM) practices:

• Monitoring for crawler emergence to ensure precise timing of insecticide applications.
• Pruning infested branches to physically reduce population levels.
• Application of horticultural oils during the dormant season to suffocate overwintering stages.
• Encouraging natural biological control agents, such as parasitoid wasps that specifically target scale populations.