Wheat stem sawfly

The wheat stem sawfly (genus Cephus) is a member of the order Hymenoptera, family Cephidae. It is a notorious pest of cereal crops, capable of causing significant yield losses by targeting wheat, rye, and barley across various temperate climatic zones worldwide.

This pest exclusively attacks grass species, with wheat being the most economically impacted host. The primary damage is caused by the larvae, which bore into the stems of the plants, creating galleries that compromise the structural integrity of the crop and disrupt the nutrient flow to the maturing heads.

The life cycle of the sawfly consists of one generation per year. Larvae overwinter in a diapause state within the base of the stubble inside a silk cocoon. Pupation occurs in the spring, followed by the emergence of adults around the time the host plants begin to head. Females insert eggs into the hollow interior of the wheat stems.

Damage symptoms often remain hidden until late in the season. As the larvae tunnel downwards, they consume the internal parenchyma, weakening the stem base. This results in premature ripening of the heads, щуплість (shriveled grain), and the most critical economic impact: lodging of the stems, which makes mechanical harvesting extremely difficult.

Integrated Pest Management (IPM) is the most effective approach for control. Key strategies include:

• tillage operations that bury infested stubble to prevent adult emergence;
• crop rotation using non-host crops to break the life cycle;
• planting resistant cultivars with stronger or pith-filled stems;
• timely application of systemic insecticides if pest pressure thresholds are exceeded.