Poplar pigmy moth

The poplar pigmy moth (Nepticula turbidella, syn. Stigmella turbidella) is a small insect belonging to the family Nepticulidae, order Lepidoptera. These moths are well-known leaf miners that specialize in attacking the foliage of aspen trees (Populus tremula) and occasionally other poplar species.

The damage is caused entirely by the larvae, which burrow into the leaf tissues. By feeding on the mesophyll, the larvae create tunnels known as mines. These mines interfere with the tree's photosynthesis process, which can lead to reduced growth vigor and premature senescence of the foliage in heavily infested trees.

The life cycle begins with the adult moth laying eggs on the leaves during the spring. Upon hatching, the larvae immediately tunnel into the leaf lamina. The larvae remain within the leaf for their entire feeding stage, eventually emerging to pupate, which typically occurs in the soil or within the leaf litter found around the base of the host tree.

Symptoms of an infestation are clearly visible as winding or spiral-shaped mines on the leaves, which often turn brown as they age. High populations of this moth can cause significant aesthetic damage in parks and nurseries, and chronic infestation may contribute to the overall decline of individual trees within a stand.

Management strategies focus on breaking the insect's life cycle. Practical measures include:

• Removal and destruction of fallen leaves to eliminate overwintering pupae.
• Monitoring of adult moth flights in early spring.
• Application of systemic insecticides at the time of larval emergence, if the economic threshold is exceeded.
• Maintaining tree vigor through proper silvicultural practices to help trees resist secondary infestations.