Sycamore moth

The Sycamore moth (Acronicta aceris) is a nocturnal moth belonging to the Noctuidae family. The adult insect is characterized by a wingspan of approximately 45–50 mm with cryptic grey-brown wing patterns, which provides excellent camouflage while resting on tree trunks during the daylight hours.

This pest primarily attacks various species of deciduous trees. The preferred hosts include maple (Acer), horse chestnut (Aesculus), lime (Tilia), and birch (Betula). In cases of large populations, they may also migrate to fruit-bearing trees, such as apple or pear, potentially causing significant foliage damage to horticultural crops.

The species typically completes one generation per year, although a partial second generation can occur under favorable climatic conditions. They overwinter as pupae within a durable silk cocoon, which is often found in crevices of tree bark, sheltered areas of fences, or beneath leaf litter near the host plant.

The damage is caused exclusively by the larvae (caterpillars). These are easily recognized by their distinct, dense covering of long yellow-to-orange hairs. Feeding larvae skeletonize leaves or consume the entire leaf blade, leaving only the primary veins intact. Repeated or severe defoliation weakens the overall vigor of the tree and diminishes its aesthetic value in landscape plantings.

Effective management and control measures involve a combination of practices:

• Sanitation, which includes the removal of infested leaf litter and debris from under the tree canopy.
• Manual removal of pupal cocoons from the bark of trunks where accessible.
• Application of selective insecticides during the early larval development stages to minimize environmental impact.
• Promotion of natural predators such as birds and parasitic wasps that help keep local populations under control.