Berry gall midge

The berry gall midge (Resseliella yagoi) is a small insect belonging to the order Diptera and the family Cecidomyiidae. It is recognized as a significant pest in berry production, often causing severe damage that remains hidden until the symptoms of stunted growth or branch dieback appear.

This pest primarily infests berry crops, with a strong preference for red and black currants as well as gooseberries. The adults are tiny midges that specifically target young shoots, utilizing cracks or wounds in the bark to initiate the colonization of the host plant.

The life cycle of the berry gall midge is synchronized with the phenology of the host plant. Adult midges emerge during the flowering period to lay eggs in crevices of the bark. Upon hatching, the larvae bore into the tissues, feeding on the cambium and living cells, which interferes with nutrient transport within the shoot.

Damage symptoms include the localized death of the bark, which becomes necrotic and sunken. As the larvae feed, the structural integrity of the shoot is compromised, making it brittle and prone to breaking during heavy winds or under the weight of the fruit. This process eventually leads to the death of the entire branch.

• Regular pruning and destruction of infested shoots.
• Protecting bark wounds with grafting wax to prevent oviposition sites.
• Monitoring the emergence of adults using traps during spring.
• Applying systemic insecticides if infestation thresholds are reached.
• Encouraging natural predators such as parasitic wasps in the orchard.

Effective management requires a combination of sanitation and monitoring. Since the larvae live protected under the bark, direct chemical control is often difficult, making preventive horticultural practices, such as maintaining healthy bark and removing infested wood, the most crucial strategies for long-term control.