Pine gall midge

Systematic position. The Pine gall midge (Inostemma matsutama) belongs to the order Hymenoptera, within the family Platygastridae. It is a specialized insect known for inducing gall formation on pine tissues, which significantly impacts the health and development of the host tree.

Host plants. The primary hosts are various species of the genus Pinus. The insect typically attacks the buds and young shoots of developing pine trees. While it can occur in mature stands, the economic impact is most severe in nurseries and young plantations where tree architecture can be permanently compromised.

Biology and life cycle. The life cycle is strictly synchronized with the phenology of the pine tree. Adults emerge during the spring to lay eggs directly into the bud primordia. Upon hatching, the larvae secrete substances that induce the host plant to form a gall, which serves as both food and a protective environment throughout the larval stages.

Nature of damage and pest status. The presence of larvae causes severe morphological changes. The formed galls disrupt the nutrient flow to the shoot, leading to stunted growth, distorted branching, and reduced photosynthetic surface area. Severe infestations can lead to the necrosis of the terminal leader, forcing the tree to develop multiple secondary leaders.

Protection and control measures. Effective management relies on a combination of silvicultural practices and chemical interventions. Early detection is critical for managing the population before it spreads.

• Sanitary pruning of infested shoots and their destruction.
• Use of registered systemic insecticides in nursery settings.
• Promoting natural predators and parasitoids.
• Regular forest monitoring during the adult flight period.