Mandibular carpenter bee

The mandibular carpenter bee (Ceratina mandibularis) belongs to the family Apidae, order Hymenoptera. While many species within the genus Ceratina are known for their pollination activities, certain species can cause agricultural damage by boring into the stems of living or dry plants to construct their nest galleries.

The primary hosts for this insect include plants with pithy stems, such as raspberry, blackberry, sunflower, and various woody ornamental shrubs. The adult females excavate tunnels through the center of these stems, which compromises the structural integrity of the plant and interrupts the normal flow of nutrients.

The life cycle is characterized by solitary nesting habits. The female selects a stem, drills a tunnel, and partitions it into individual brood cells using plant fibers. Each cell contains a pollen ball and an egg. The development process, including the larval and pupal stages, takes place entirely within the protection of the stem's central pith.

The economic impact of this pest involves mechanical damage to the host plant and the creation of entry points for opportunistic pathogens. Stems weakened by larval activity are prone to breaking under wind pressure or heavy foliage, and the open tunnels can harbor fungi and bacteria, leading to tissue decay and plant wilting.

Effective management strategies focus on sanitation and cultural practices. Growers should prune and remove infested or dead stalks in the autumn or early spring to eliminate overwintering populations. Additionally, maintaining healthy plant vigor through balanced fertilization can sometimes help plants better withstand or recover from minor infestation pressures.