Flax seed midge

The flax seed midge (Dasineura semenivora) is a small dipteran insect belonging to the family Cecidomyiidae. It is recognized as a significant agricultural pest that specifically targets flax plants (Linum usitatissimum). Because of its specialized feeding habits, it can cause severe economic damage to seed production in flax-growing regions.

This pest primarily attacks the developing seeds within the flax capsules. The damage occurs when the adult females lay eggs into the buds or flowers. Upon hatching, the larvae penetrate the ovary and consume the developing seeds. As a result, the seeds fail to mature properly, becoming hollow or destroyed, which leads to substantial losses in seed yield and germination rates.

The life cycle of the flax seed midge is closely linked to the phenology of the flax plant. The midge overwinters in the soil as larvae or pupae within cocoons. As temperatures rise and flax enters the budding and flowering stages, the adults emerge to mate and oviposit. This specific timing makes the crop highly vulnerable during the period of capsule formation.

In terms of damage assessment, infested capsules often exhibit signs of premature browning, distortion, or stunted development. Upon examination, farmers will find larvae inside the capsules, and the internal tissues of the seeds will be entirely or partially consumed. The economic impact is determined by the percentage of damaged capsules and the resulting reduction in the quality of the harvested grain.

Integrated management practices to control the flax seed midge include:

• Implementation of crop rotation to break the pest's life cycle.
• Deep autumn tillage to bury overwintering larvae and prevent adult emergence.
• Maintaining proper isolation distances from the previous year's flax fields.
• Monitoring adult population levels during the bud stage and applying insecticides if economic thresholds are exceeded.