Myrtle whitefly

Systematic position. The Myrtle whitefly (Bemisia myricae) belongs to the order Hemiptera and the family Aleyrodidae. It is a significant agricultural pest known for its high reproductive capacity and ability to adapt to various environmental conditions in greenhouses and warmer outdoor climates.

Host range. The primary host plants for Bemisia myricae are citrus species, including lemons, oranges, and mandarins. However, its host range is quite broad, extending to various ornamental plants like Myrtus communis and several species of tropical trees, causing management challenges in diversified agricultural systems.

Biology and life cycle. The life cycle consists of the egg stage, four larval instars, and the adult stage. Eggs are typically laid on the underside of leaves. After hatching, the first instar larvae (crawlers) actively seek a site for feeding, while the subsequent stages remain sessile. The speed of development is heavily influenced by ambient temperature, with warmer conditions significantly accelerating population growth.

Damage and economic importance. Feeding by Bemisia myricae involves the extraction of plant sap, which causes leaf chlorosis, curling, and early senescence. Beyond direct feeding damage, the excretion of honeydew promotes the growth of sooty mold, which blocks photosynthesis and reduces the marketability of fruits due to heavy fungal staining.

Protection measures. Effective control requires an integrated approach.

• Monitoring using yellow sticky traps is essential for early detection.
• Application of selective systemic insecticides during the early infestation stage.
• Implementation of biological control using parasitoid wasps like Eretmocerus species.
• Maintaining optimal orchard hygiene and pruning to reduce humidity and micro-climate favorability for the pest.