Radish gall midge

The radish gall midge (Gephyraulus raphanistri) is a small dipteran insect belonging to the family Cecidomyiidae. It is a highly specialized pest that primarily targets crops within the Brassicaceae family, often causing significant economic losses in seed production fields.

This pest affects various cultivated and wild crucifers, including radish, rapeseed, and mustard. The larvae are the primary damaging stage, as they feed internally on the floral buds, preventing the formation of pods and destroying the potential seed yield of the host plants.

The life cycle of the midge is synchronized with the phenology of its host plants. The insect typically overwinters as a larva in the soil. Upon the arrival of warmer temperatures, the pupation phase occurs, followed by the emergence of adults, which lay their eggs directly into the developing buds of the host plant.

Signs of infestation include the abnormal swelling and deformation of flower buds, which fail to open properly. These distorted buds, often referred to as galls, contain the larvae. The primary damage is the complete abortion of the flowers and subsequent loss of seeds, which can severely impact the profitability of the crop.

Effective management requires a combination of cultural and chemical strategies to reduce population pressure:

• Implementing strict crop rotation to break the pest's life cycle.
• Removal and destruction of wild cruciferous weeds surrounding the fields.
• Deep plowing in autumn to disturb and destroy overwintering larvae in the soil.
• Monitoring adult flight activity using yellow sticky traps to time insecticide applications correctly.
• Choosing resistant varieties where available and maintaining optimal plant health.