Larch sawfly

Systematic position
The Larch sawfly, taxonomically recognized in scientific studies as Agathis pumila (often associated with the Pristiphora complex), belongs to the order Hymenoptera and the family Tenthredinidae. It is a specialized forest pest known for its host specificity towards larch trees.

Host plants
The primary hosts of this species are various larch (Larix) species. These insects are capable of colonizing both native forest stands and artificial plantations. Their feeding activities are specifically confined to the needles, making larch forests particularly vulnerable during the growing season.

Biology and life cycle
The life cycle encompasses four stages: egg, larva, pupa, and adult. The females insert their eggs into the tissues of new needle growth. The larvae, which resemble caterpillars, feed aggressively throughout the summer months. The species typically overwinters as a prepupa within a tough, brown silken cocoon located in the soil or leaf litter beneath the host tree.

Damage and pest status
Damage is primarily inflicted by the larvae, which consume the needles of the larch trees. Defoliation is the most prominent symptom; in severe outbreaks, trees may lose nearly all their needles by mid-summer. Repeated annual defoliation weakens the trees, leading to reduced growth increments, branch dieback, and increased susceptibility to secondary pests such as bark beetles.

Protection measures
Managing populations of the Larch sawfly requires an integrated pest management approach:

• Mechanical destruction of cocoons through soil cultivation under affected trees in the autumn.
• Biological control by preserving natural enemies, including predatory wasps and insectivorous birds.
• Targeted application of biological insecticides, such as bacteria-based agents, during early larval stages.
• Chemical control applications strictly restricted to areas with high infestation levels to prevent significant forest damage.