Zelkova aphid

Taxonomic classification. The Zelkova aphid (Tinocallis zellcowae) belongs to the order Hemiptera and the family Aphididae. It is a highly specialized species that primarily targets members of the Ulmaceae family, particularly trees in the genus Zelkova.

Host plants and damage potential. This pest primarily infests various species of Zelkova trees. By feeding on phloem sap, the aphid removes essential nutrients from the tree, which can lead to severe stress, stunted growth, and a significant reduction in the aesthetic value of the ornamental planting.

Biology and lifecycle. The lifecycle of Tinocallis zellcowae is synchronized with the bud burst and leaf development of the host tree. It undergoes multiple generations, with both apterous (wingless) and alate (winged) forms appearing during the season. Overwintering occurs in the egg stage, typically positioned within crevices of the tree bark.

Damage patterns. Damage is characterized by leaf chlorosis, curling, and early senescence. Furthermore, the aphids secrete honeydew, which promotes the growth of sooty mold. This layer of fungus inhibits photosynthesis and can permanently mark the foliage, making the tree look unattractive and reducing its overall health.

Control measures. Integrated pest management strategies are recommended to mitigate the impact of this aphid:

• Regular monitoring of the canopy, especially during the spring growth flush.
• Application of systemic insecticides or contact sprays targeting infested foliage.
• Encouraging natural predators such as lady beetles, lacewings, and parasitic wasps.
• Maintaining vigorous tree health through proper fertilization and watering to improve natural resistance.