Willow gall midge

Systematic position. The willow gall midge (Rabdophaga rigidae) belongs to the order Diptera and the family Cecidomyiidae. This insect is a specialized phytophage that targets various willow species (Salix), causing significant physiological changes in the host plant.

Host plants. The primary hosts are shrub and tree forms of willows. The pest is particularly problematic in nurseries producing willow rods or in ornamental gardens, where the aesthetic value of the trees is essential.

Biology and life cycle. Adult midges lay their eggs in the buds or young stems of the willow. Upon hatching, the larvae stimulate the plant to grow abnormal tissues, creating structural formations known as galls. The larvae overwinter inside these galls, protected from harsh weather, and pupate in the spring before emerging as adults.

Damage and economic impact. The presence of galls disrupts the normal development of the shoots, leading to stunted growth, twisting, or branch dieback. For commercial willow producers, this damage significantly reduces the yield and quality of the raw material, making the rods unusable for basketry or construction purposes.

Control measures. Integrated pest management strategies include:

• Pruning and destroying infested twigs containing galls before the adult insects emerge.
• Application of systemic insecticides during the peak egg-laying and larval emergence period.
• Maintaining healthy planting stock and ensuring adequate spacing between nursery rows.
• Regular monitoring of the trees during the early growth season to detect and remove galls promptly.