Raspberry cane midge

Resseliella theobaldi

1. Identification

• Common name: Raspberry cane midge
• Scientific name: Resseliella theobaldi Barnes
• Order: Diptera
• Family: Cecidomyiidae

2. Pest description

• Very small adults (2–3 mm), resembling small mosquitoes.
• Fragile body, transparent wings and long legs.
• Whitish to orange larvae, apodous, develop inside the canes.
• Pupation in the soil, in shallow chambers.
• Eggs deposited in cracks or wounds in young canes.

3. Main hosts

• Raspberry (main host).
• May affect other Rubus. species
• Most frequent damage in intensive orchards and in vigorous shoots.

4. Symptoms and damage

• Longitudinal cracks in young canes.
• Wilting and easy breakage of the shoots.
• Internal necrosis caused by larval feeding.
• Reduced plant vigor and decreased production.
• Greater susceptibility to secondary infections (opportunistic fungi).

5. Biological cycle

• Several generations per year, depending on temperature.
• Adults emerge from the soil and lay eggs in damaged young canes.
• Larvae feed in the internal tissues for 2–3 weeks.
• Pupation in the soil, a few centimeters deep.
• Cycle favored by tender shoots and high soil moisture.

6. Monitoring

• Observation of cracks and necrosis in young canes.
• Checking for wilted or brittle shoots.
• Sampling of canes to detect internal larvae.
• Regular monitoring during the active growth period.
• Recording of favorable conditions (high humidity and vigorous shoots).

7. Management measures

• Cultural: removal and destruction of attacked canes, improvement of air circulation, reduction of excessive humidity and avoiding wounds on shoots during cultural operations.
• Biological: conservation of natural enemies present in the soil and use of entomopathogens when authorized.
• Integrated protection: continuous monitoring, interventions targeted only when necessary, adequate management of plant density and integration of cultural practices to reduce oviposition sites.

Bibliographic references

• EPPO Global Database – Resseliella theobaldi.
• CABI Invasive Species Compendium – R. theobaldi.
• Cross, J. V. et al. (2001). Pests of cane fruit crops.
• Moore, J. et al. (2010). Biology and control of gall midges in Rubus crops.