Tree bumblebee

Systematic position: The tree bumblebee (Bombus hypnorum) is a member of the Hymenoptera order and the Apidae family. While commonly regarded as a beneficial pollinator, in high-intensity greenhouse environments, it can become a structural pest due to its tendency to nest in buildings and equipment.

Crops affected: The species does not feed on crops in the traditional sense of a pest, but its presence causes significant damage to tomatoes and other high-value greenhouse crops. In their search for nectar, these bees may pierce the skin of developing fruits, causing localized tissue death and making the products unsuitable for commercial sale.

Biology and development cycle: The colony cycle is annual. A queen that has overwintered emerges in early spring to establish a nest, often preferring cavities in trees or human-made structures. The colony progresses through larvae and pupae stages, peaking in mid-summer. By late summer, new queens are produced, and the original colony eventually dies out, leaving the new queens to hibernate.

Nature of damage and economic impact: The primary nuisance is the destruction of infrastructure. Tree bumblebees frequently nest in wall cavities, loft insulation, and greenhouse structures, damaging building materials. Their defensive behavior around nests makes it difficult for farm laborers to manage plants safely, potentially leading to productivity losses during peak harvest times.

Management measures: Controlling tree bumblebee activity requires proactive structural maintenance to exclude them from growing areas:

• Sealing cracks in building foundations and greenhouse walls;
• Installing high-quality mesh screens on all ventilation systems;
• Removing debris and potential nesting sites from the perimeter of agricultural buildings;
• Regular monitoring during early spring to prevent queens from establishing nests in sensitive zones.