Cambium gall midge

Systematic position: The cambium gall midge Resseliella silvana belongs to the order Diptera and the family Cecidomyiidae. It is a specialized insect pest that targets the cambium layer of coniferous trees, significantly affecting tree health.

Crops damaged: This pest primarily affects coniferous species, with a notable preference for Fir (Abies). It is attracted to trees with compromised bark integrity or those stressed by environmental factors, where it easily gains access to the nutrient-rich cambium.

Biology and life cycle: The life cycle comprises egg, larval, pupal, and adult stages. Adult midges lay eggs into bark crevices. The resulting orange-red larvae feed underneath the bark, creating complex galleries. Once fully developed, the larvae descend to the soil or leaf litter to pupate, emerging as adults in the following season.

Nature of damage: The larvae disrupt the tree's vascular system by feeding on the cambium and phloem. This causes localized bark necrosis and resin exudation. Severe infestations restrict nutrient flow, leading to branch dieback, crown thinning, and, in extreme cases, the death of the tree due to secondary fungal or bark beetle invasions.

Protection measures: Effective management involves integrated forest pest control. Recommended strategies are:

• Sanitary forest management: removing infested trees and slash to reduce the population.
• Silvicultural practices: thinning and maintaining healthy forest stands to enhance natural resistance.
• Chemical control: applying insecticides during the peak adult flight period when necessary.
• Biological control: monitoring and encouraging native predators and parasitoids that target midge larvae.