Buckthorn whitefly

Systematic position: The buckthorn whitefly (Dialeurolobus rhamni) belongs to the order Hemiptera and the family Aleyrodidae. This species is an obligate feeder on woody plants, specifically focusing on the genus Rhamnus (buckthorn) as its primary host plant.

Crops and economic impact: The pest primarily affects species of buckthorn. While it is often considered a minor pest in wild habitats, in nurseries or cultivated landscape gardens, it can cause significant aesthetic damage. Heavy infestations drain plant sap, leading to stunted growth and potentially weakening the plant against environmental stressors.

Biology and life cycle: The life cycle of Dialeurolobus rhamni follows a typical whitefly pattern: egg, several larval instars, a pupal stage, and the adult winged stage. Overwintering occurs mainly as puparia attached to the abaxial (lower) surface of the leaves or in the bark crevices of the host plant, emerging as adults in the spring as temperatures rise.

Nature of damage: Damage is caused by both adults and nymphs piercing the plant tissues to feed on phloem sap. This feeding process causes chlorosis, leaf curl, and drop. Furthermore, the excretion of honeydew promotes the growth of sooty mold, which coats the foliage and further impedes the plant's ability to photosynthesize effectively.

Protection measures: To manage populations of buckthorn whitefly, an integrated pest management (IPM) program is recommended:

• Pruning and removing infested branches to reduce local populations.
• Application of insecticidal soaps or oils during the early nymphal stages.
• Using systemic insecticides if the infestation level poses a threat to plant health.
• Maintaining plant vigor through proper fertilization and watering to improve natural resistance.