Canary-shouldered thorn

The Canary-shouldered thorn (Ennomos alniaria) is a moth belonging to the order Lepidoptera and the family Geometridae. This species is native to many temperate regions and is commonly found in deciduous woodlands, gardens, and parklands, where it can act as a pest on various woody plants.

The larvae, or caterpillars, are known to feed on a variety of broad-leaved trees and shrubs. Common host plants include alder, birch, lime, hazel, and several fruit-bearing trees, such as apple, pear, and plum. Their feeding activity can be particularly damaging to young or stressed trees in managed orchards.

The biological cycle consists of a single generation per year. The species overwinters in the egg stage, with eggs typically laid in small clusters on the bark of host tree branches. As temperatures rise in spring, the larvae hatch and immediately begin feeding on the developing foliage.

The damage caused by the larvae manifests as leaf tissue consumption, often leading to significant defoliation during peak population years. The larvae are experts in camouflage, resembling small twigs, which makes early detection difficult for growers. Repeated defoliation weakens the overall health of the tree and impacts photosynthetic capacity.

Effective management strategies should focus on both prevention and control. Growers are advised to monitor their trees closely during the early spring. Key strategies include:

• Physical removal of egg masses during winter dormant pruning.
• Application of biological insecticides containing Bacillus thuringiensis in early larval stages.
• Targeted chemical control using approved insecticides if infestations reach threshold levels.