Ceratina cyanea

Ceratina cyanea, often referred to as the small blue carpenter bee, belongs to the Apidae family within the order Hymenoptera. While many bees are beneficial pollinators, this specific species is known to cause damage to various garden crops by nesting inside the pithy stems of plants.

The primary hosts for this insect include plants with soft or hollow stems, such as raspberries, blackberries, roses, and various herbaceous perennials. The bees are particularly attracted to exposed stems after pruning or those damaged by environmental factors, as these provide easy access to the internal tissue.

The biological lifecycle of the species begins in the spring. A female bee clears a tunnel in the plant's stem, constructs individual brood cells divided by partitions made of sawdust and saliva, and deposits an egg in each. The larvae develop within these chambers, often weakening the structural integrity of the stem.

Damage caused by Ceratina cyanea is characterized by hollowed-out stems, leading to wilting, stunted growth, and a significant reduction in fruit yield. Furthermore, the nesting activity compromises the plant's vascular system and creates entry points for fungal pathogens that can lead to systemic stem diseases.

Effective management strategies focus on sanitation and preventative physical barriers. Gardeners should implement the following measures:

• Regularly prune and remove all dead, diseased, or damaged stems from the garden.
• Seal larger pruning cuts with pruning paste or horticultural wax to prevent bees from entering.
• Dispose of prunings immediately rather than leaving them in piles near host plants.
• Monitor for entry holes in stems during early spring to catch infestations early.