Web-spinning sawfly

The web-spinning sawfly (Pamphilius multisignatus) belongs to the order Hymenoptera and the family Pamphiliidae. Unlike many other sawfly larvae, these species are known for their unique ability to weave silken webs, which serve as protective shelters while they feed on the host plant's foliage.

This pest primarily affects a variety of rosaceous plants, with a strong preference for pome and stone fruit trees. In agricultural settings, it can be found in orchards and nursery plantations, where its presence often goes unnoticed until the characteristic leaf damage becomes clearly visible to the grower.

The life cycle of this insect is synchronized with the seasonal development of its host plants. It overwinters as a larva in the soil, often at a depth of several centimeters. In the spring, the larvae pupate, and the adult sawflies emerge to mate. Females then deposit eggs on the undersides of leaves, and the hatched larvae begin constructing their silk-bound retreats immediately.

The primary damage is caused by larvae that roll or fold leaves using silk threads to create tubes or nests. They feed on the leaf tissues within these enclosures, leaving only the primary veins behind. Severe infestations can cause significant defoliation, which stresses the tree, inhibits growth, and reduces the yield for the current and following seasons.

Control measures should be implemented strategically to be effective. For small-scale gardens, manual removal and destruction of the silk nests is a viable option. For larger commercial orchards, chemical control using targeted insecticides is recommended, particularly during the early larval stage before they have fully established their protected webs. Regular soil cultivation in the fall helps to expose overwintering larvae to predators and environmental stresses.