Elm psyllid

Systematic position. The Elm psyllid (Trioza neglecta) belongs to the order Hemiptera and the family Triozidae. These insects are specialized pests that inhabit host plants and are well-known for inducing gall formation on the foliage of specific tree species.

Host plants. This species is primarily associated with trees of the genus Ulmus (elms). It is commonly found in forest ecosystems, urban landscaping, and nurseries where elm trees are grown for their ornamental value or timber production.

Biology and life cycle. The life cycle of Trioza neglecta is synchronized with the growth phases of its host tree. After overwintering as adults, females oviposit on developing leaves in the spring. As the nymphs hatch, they begin to feed on the plant sap, triggering localized changes in the leaf tissue architecture.

Damage and economic impact. The feeding activity of the nymphs leads to the development of characteristic leaf galls. These structures provide protection for the developing insects but cause significant deformation of the leaves. Severe infestations can lead to stunted growth, early leaf senescence, and reduced tree vigor, which impacts the health of the entire plant.

Control measures. Management of Elm psyllid typically involves a combination of cultural and chemical controls. Pruning and destroying heavily infested twigs in early stages can reduce population levels. In cases of significant infestation, applying systemic insecticides during the early growing season is the most effective way to eliminate nymphs residing inside the galls.