Sainfoin blossom midge

Systematic position: The sainfoin blossom midge (Contarinia onobrychidis) belongs to the order Diptera and the family Cecidomyiidae. It is a specific pest that targets forage legumes, particularly sainfoin.

Host crops: This pest exclusively infests sainfoin (Onobrychis species). It primarily affects the reproductive parts of the plant, specifically targeting the flower buds, which makes it a major concern for seed production fields rather than hay production.

Biology and life cycle: The midge typically completes one generation per year. It overwinters as mature larvae within cocoons located in the soil. Adults emerge in late spring, coinciding with the early budding stage of the sainfoin crop. Females lay their eggs into the developing flower buds, where the larvae feed once they hatch.

Nature of damage: Larval feeding inside the buds causes the tissue to deform and swell, preventing the flower from blooming. These damaged buds eventually turn brown and fall off the plant. Severe infestations can result in the loss of a significant percentage of the seed yield, as the midge prevents the development of the seed-bearing organs.

Control measures: Integrated pest management is essential for controlling Contarinia onobrychidis. Key practices include spatial isolation from older infested fields and deep plowing after harvest to destroy the overwintering larvae in the soil. Chemical control with appropriate insecticides is recommended only during the adult flight period before egg-laying occurs.