Nematus tibialis

Locust sawfly

Description

Nematus tibialis, known as the locust sawfly, is a sawfly species native to North America that has spread across Europe, particularly in countries such as Austria, Germany, Slovakia, Hungary etc. Its larvae primarily feed on Robinia pseudoacacia, creating characteristic feeding damage on leaves. The larvae consume the central parts of leaflets, leaving irregular holes that can negatively impact the tree’s aesthetic appearance. Although infestations do not usually pose a serious threat to tree health, severe defoliation may reduce photosynthetic capacity, leading to a temporary decline in vitality. The species has been recorded in urban and natural habitats, where it spreads naturally without the need for human-driven dispersal.

Symptom

The larvae feed on Robinia pseudoacacia leaves, creating irregularly shaped holes, particularly in the center of leaflets. In cases of severe infestation, entire leaflets may be completelly missing.

Tree Species: Black Locust

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: Yes

Present in EU: Yes