Wheat stem braconid

The wheat stem braconid (Coelinius niger) is an insect belonging to the order Hymenoptera and the family Braconidae. Unlike most members of the Braconidae family, which are typically parasitic, this species is known as a phytophage, as its larvae develop inside the stems of cereal crops, causing damage to the plants.

This pest primarily attacks wheat (both winter and spring varieties), rye, and occasionally barley. It is distributed across many regions where small grains are cultivated, often becoming a significant issue in areas with intensive monoculture of cereals, which provides the pest with constant and abundant host plants.

The life cycle of the wheat stem braconid is univoltine, meaning one generation per year. Adults emerge in the spring, typically when the cereals are at the stem elongation stage. The females deposit eggs inside the plant stems. The larvae feed on the internal tissues, disrupting the growth of the stalk and eventually pupating inside the stem cavity, where they remain to overwinter.

Damage to the crop occurs when the larvae consume the internal vascular tissues. This interruption in nutrient flow prevents the proper development of the ear, leading to "shriveled" or underweight grains. In severe cases, the structural integrity of the stem is compromised, leading to premature lodging and a measurable loss of total grain yield.

Integrated pest management strategies are crucial for controlling this insect. These include:

• practicing crop rotation to break the pest's reproductive cycle;
• deep plowing of stubble fields immediately after harvest to destroy overwintering sites;
• thorough removal of wild grasses that can serve as alternative hosts;
• targeted insecticide applications during the adult emergence phase before egg-laying begins.