Lucerne flower midge

The Lucerne flower midge (Contarinia medicaginis) belongs to the order Diptera and the family Cecidomyiidae. It is a highly specialized agricultural pest that primarily targets alfalfa, leading to significant yield losses in seed production fields.

This pest exclusively infests alfalfa plants. The damage is strictly limited to the reproductive organs, specifically the flower buds, where the larvae feed during the most vulnerable stage of the plant's development, effectively halting the formation of seeds.

The life cycle begins with larvae overwintering in the soil within silken cocoons at a shallow depth. In the spring, they pupate and emerge as adults. The female midges lay eggs into the developing floral clusters, and the hatched larvae begin their feeding process immediately upon reaching the host tissue.

The signs of infestation are distinct: the flower buds become deformed, swollen, and exhibit a globular appearance, changing to a yellow or brownish color. These "galls" prevent the flower from opening. As the larvae consume the interior tissue, the bud withers and drops off prematurely, directly reducing the total seed yield.

To control this pest, integrated management strategies are required:

• Early mowing of the alfalfa crop to remove the infested buds before larvae drop to the soil.
• Application of systemic insecticides during the early bud formation stage if the infestation threshold is reached.
• Deep autumn plowing to bury the overwintering larvae and disrupt their life cycle for the following season.