Sophora seed chalcid

The Sophora seed chalcid (Bruchophagus sophorae) is a specialized insect pest belonging to the order Hymenoptera and the family Eurytomidae. This species is highly host-specific, primarily targeting the seeds of the Japanese pagoda tree (Styphnolobium japonicum). As a gall-forming wasp relative, it poses a specific threat to nurseries and landscape plantings.

The life cycle of this pest is synchronized with the plant's development. Adult wasps emerge during the pod-setting phase. Females use their ovipositors to penetrate the developing pods and lay eggs directly into the seeds. The larva feeds entirely within the seed, consuming the internal tissues until it pupates and eventually emerges as an adult, leaving a distinctive exit hole.

Damage caused by Bruchophagus sophorae is primarily internal and hidden until the final stages of the pest's lifecycle. Infected pods may look normal from the outside, but their weight is significantly reduced, and the interior of the seeds is hollowed out. This makes the seeds non-viable, which is a major concern for silviculture and propagation efforts.

The pest's economic importance is tied to the degradation of high-quality seed stocks. When infestations are severe, seed production can be almost completely lost. Because the larvae are protected by the seed coat, contact insecticides are ineffective once the larvae have entered the seed, making management timing critical.

Recommended management practices include:

• Strict sanitation by collecting and disposing of all fallen pods to remove overwintering larvae.
• Timing insecticide applications to coincide with the period of adult emergence and egg-laying.
• Maintaining healthy tree vigor to help the plant withstand minor losses.
• Monitoring adult wasp activity using yellow sticky traps during the flowering and fruit formation periods.