Citrus whitefly

The Citrus whitefly (Dialeurodes citri) is a destructive sucking insect classified within the family Aleyrodidae. Originating from Asia, this species has become a significant concern for citrus growers worldwide, particularly in warm temperate and subtropical climates, where it can rapidly colonize both orchard trees and nursery stock.

While citrus trees remain the primary host, this polyphagous pest affects a wide range of botanical species. Common ornamental plants and shrubs, such as gardenia, jasmine, and privet, frequently serve as reservoirs for the whitefly, allowing the population to persist even in the absence of citrus crops.

The life cycle of Dialeurodes citri consists of an egg, three larval stages, a puparium, and the adult stage. The larval stage is relatively immobile; after the initial 'crawler' phase, they settle on the abaxial side of the leaf, piercing the epidermis to feed on phloem sap. The pupal stage is protected by a waxy test, making it highly resistant to many standard pesticide applications.

The primary damage results from direct sap depletion and the production of copious amounts of honeydew. This sugary secretion covers the foliage and fruit, acting as a substrate for sooty mold growth. The resulting black coating severely hampers photosynthesis, stunts tree growth, reduces overall vigor, and causes significant cosmetic damage to fruit, often leading to commercial rejection.

Effective management strategies require an integrated approach (IPM). Key tactics include:

• Utilizing biological control agents such as the parasitoid wasp Encarsia lahorensis.
• Applying systemic neonicotinoid or horticultural oil treatments during active crawler stages.
• Maintaining proper canopy hygiene through regular pruning to improve airflow.
• Implementing sticky yellow traps for monitoring adult flight activity.
• Ensuring proper quarantine protocols for incoming plant materials.