Poplar sawfly

Systematic position. The Poplar sawfly (genus Trichiocampus) belongs to the order Hymenoptera and the family Tenthredinidae. These insects are significant defoliators that pose a consistent threat to poplar and willow species in both natural forests and urban landscapes.

Host plants and damage symptoms. The primary hosts are various species of the genus Populus and Salix. The larvae, often called "false caterpillars," feed gregariously in early instars, skeletonizing leaves, while older larvae consume entire leaf blades. The damage is characterized by a "lace-like" appearance of the canopy, eventually leading to complete defoliation.

Biology and life cycle. Trichiocampus species typically undergo one or two generations annually. They overwinter as fully grown larvae within sturdy cocoons located in the soil or forest floor litter. Adults emerge in spring, with females utilizing their saw-like ovipositors to insert eggs into leaf tissue, which often induces minor tissue deformation.

Pest significance. Severe infestations cause substantial stress to the host trees. Repeated defoliation events throughout the growing season reduce the tree's vigor, suppress radial growth, and make the affected plants increasingly susceptible to secondary pests like wood-boring beetles and opportunistic fungal pathogens.

Control measures. Integrated Pest Management (IPM) is essential for maintaining tree health:

• Cultural control involving soil tillage under the canopy to disrupt overwintering cocoons.
• Regular monitoring of foliage starting in late spring to detect early larval colonies.
• Application of biological control agents, such as Bacillus thuringiensis, which are effective against young larvae.
• Targeted use of systemic insecticides during severe outbreaks to minimize environmental impact.