Lime bark moth

Systematic position: The lime bark moth (Chrysoclista linneella) is a species of moth in the family Agonoxenidae (order Lepidoptera). This insect is relatively small but notable for its distinctively colored forewings, which feature metallic golden or orange markings. It is primarily recognized as a specialized pest of lime (linden) trees.

Host plants: This moth is essentially monophagous or oligophagous, targeting various species of the genus Tilia (lime). It is most frequently found on established trees in urban environments, parks, and tree-lined streets, where it thrives by exploiting the thick, textured bark of the tree trunks and main branches.

Biology and life cycle: The species overwinter as larvae (caterpillars) underneath the bark of host trees. As temperatures rise in spring, they complete their development, pupate within the bark tunnels, and emerge as adults during the summer months. The adult moths are nocturnal and mate shortly after emergence to lay eggs in crevices of the bark.

Damage and harmfulness: The primary damage is caused by the larval stage. Caterpillars tunnel through the bark and the cambium layer, creating irregular galleries. This feeding activity disrupts the tree's nutrient transport system. Over time, the bark may become cracked and necrotic, leading to the decline of branch health and, in severe cases of infestation, the death of limbs.

Protection measures: Management of Chrysoclista linneella is challenging due to the larvae's protected position within the bark. Strategies include:

• Pruning and removing infested branches to reduce local population density.
• Maintaining tree vigor through proper irrigation and fertilization.
• Applying systemic insecticides during the emergence of adult moths or the early stages of larval development.
• Monitoring trunks for signs of larval galleries and bark discolouration.