Birch knot-horn moth

Systematic position. The birch knot-horn moth (Acrobasis betulella) belongs to the order Lepidoptera and the family Pyralidae. It is a specialized lepidopteran pest that primarily focuses its life cycle on birch species, significantly impacting both forestry and ornamental plantings.

Host plants. The primary host for this species is the birch tree (Betula spp.). While it often thrives in natural birch forests, it frequently migrates into urban parks, nurseries, and managed landscapes, where its impact is more noticeable due to the reduced aesthetic value of the affected trees.

Biology and life cycle. This pest undergoes a complete metamorphosis. Larvae typically overwinter in silk hibernacula (small cocoons) constructed in branch crotches or bark crevices. In the spring, as temperatures rise and birch buds begin to break, the larvae emerge to feed, eventually pupating within the silk-bound foliage nests they create.

Damage and economic significance. Larval activity is characterized by the consumption of developing buds, followed by the mining and tying of leaves and shoots with silk webbing. This feeding pattern often results in stunted growth, shoot dieback, and an unsightly appearance of the canopy. In extreme cases, repeated infestations can severely stress the host plant.

Management and control. Integrated pest management (IPM) strategies for Acrobasis betulella include:

• Regular inspections of birch saplings during the early spring to identify and remove infested shoots.
• Pruning and destruction of larval webs during the growing season to prevent further spread.
• Application of biological control agents, such as Bacillus thuringiensis, which target larvae without harming beneficial insects.
• Use of targeted insecticides if the infestation levels exceed localized economic thresholds in nurseries.