Cactus mealybug

The cactus mealybug (Eriococcus cactearum) belongs to the Eriococcidae family and is a specialized pest primarily affecting succulent plants, particularly cacti. Unlike common mealybugs, this species creates distinct protective scale-like coverings, significantly increasing their resistance to many standard contact insecticides.

This pest exclusively targets members of the Cactaceae family. It is frequently observed in private collections and greenhouses, infesting popular genera such as Opuntia, Mammillaria, and Gymnocalycium. They tend to hide in secluded areas such as areoles, rib crevices, and near the root neck of the plant.

The biological development of Eriococcus cactearum involves several stages: eggs, mobile nymphs (crawlers), and sessile adults. Adult females remain fixed in one location, producing eggs protected by a waxy test. The tiny crawlers are the primary dispersal stage, often spreading between plants via air currents or direct physical contact during maintenance.

Damage to the plant is caused by the extraction of phloem sap, which leads to metabolic stress. Initial symptoms include chlorotic spots on the epidermis, which can later turn into necrotic lesions. These wounds often serve as entry points for secondary infections like fungal or bacterial rot, which can cause severe systemic damage and even the death of the specimen.

Effective control requires a multi-faceted approach. Implementing strict quarantine measures for new plants is crucial for prevention. For active infestations, systemic insecticides such as neonicotinoids are the most effective choice, as they allow the plant to absorb the toxin and kill the pests from within.

• Always treat twice with a 10–14 day interval to catch nymphs emerging from eggs.
• Use manual removal for light infestations alongside chemical treatments.
• Ensure good ventilation to prevent secondary fungal outbreaks.