Black-horned sawfly

The black-horned sawfly (lat. Pteronidea nigricornis) is a destructive insect belonging to the order Hymenoptera and the family Tenthredinidae. This pest is primarily known for infesting various berry shrubs, particularly gooseberries and currants, where it can cause severe defoliation if left unmanaged.

Systematically, this species is classified as a leaf-feeding sawfly. The adult insects are small, wasp-like creatures, while the larval stage, known as false caterpillars, is the primary destructive agent responsible for the rapid consumption of leaf tissue.

The lifecycle of this pest is synchronized with the growth stages of its host plants. Overwintering occurs in the soil as prepupae protected within cocoons. As spring temperatures rise, adults emerge, mate, and lay eggs on the undersides of leaves, starting the cycle of damage for the new growing season.

The damage caused by larvae is significant. They feed voraciously, often consuming leaf tissue until only the main veins remain, a process known as skeletonization. This heavy feeding pressure weakens the host plant, significantly reduces fruit quality and size, and can lead to the overall decline of the shrub vitality.

Integrated Pest Management (IPM) strategies are essential for control:

• Cultivating the soil around the base of bushes in autumn to expose overwintering cocoons.
• Manual removal of young larvae during the early stages of infestation.
• Application of targeted insecticides during the larval hatching phase if thresholds are exceeded.
• Encouraging natural predators, such as parasitic wasps and predatory beetles, to help suppress population levels.