Purslane sawfly

Taxonomic position. The purslane sawfly, Schizocerella pilicornis, is a member of the order Hymenoptera and the family Tenthredinidae. This insect is highly host-specific, having evolved a specialized relationship with plants belonging to the genus Portulaca.

Host plants. The primary host is common purslane (Portulaca oleracea), a widespread weed that can be aggressive in agricultural fields. In some regions, the sawfly is studied as a potential biological control agent to manage purslane infestations. It also attacks ornamental varieties like Portulaca grandiflora.

Biology and lifecycle. The lifecycle consists of egg, larval, pupal, and adult stages. Females lay their eggs directly into the leaf tissue. Upon hatching, the larvae begin to feed, often mining inside the leaves. Pupation typically occurs in the soil, where the larva creates a protected cocoon made of soil particles to undergo metamorphosis.

Damage and economic impact. The larvae cause damage by mining and skeletonizing the leaves. Initially, the injury appears as irregular mines, but heavy infestations result in the total consumption of the leaf lamina. This significantly impairs the plant's photosynthetic ability, leading to stunted growth or death of the host plant if the population density is high.

Control measures. In agricultural contexts, Schizocerella pilicornis is often considered beneficial due to its role in suppressing purslane weeds. For home gardeners protecting ornamental portulaca, the following methods are recommended:

• Hand-picking and destroying infested leaves.
• Applying contact or systemic insecticides during the early larval stage.
• Cultivating the soil around the plants to disrupt the pupation cycle of the larvae.