Locust bean weevil

Systematic position. The locust bean weevil (lat. Bruchidius anxius) belongs to the order Coleoptera and the family Bruchidae. It is a highly specialized insect pest that has evolved to feed exclusively on the seeds of certain leguminous trees.

Host plants. The primary host for this beetle is the Black Locust (Robinia pseudoacacia). The pest causes significant economic losses by damaging seeds while they are still developing in the pods on the trees, as well as during the storage of harvested seeds.

Biology and lifecycle. The lifecycle is entirely contained within the seed. Female beetles lay eggs on the surface of maturing pods. Once hatched, the larvae bore through the pod wall and into the seed. They consume the internal tissues, developing through larval stages into pupae, and eventually emerging as adults by creating a circular exit hole.

Damage and economic significance. The feeding activity of the larvae destroys the embryo and endosperm of the seeds, rendering them completely non-viable. In cases of severe infestation, Bruchidius anxius can compromise the entire seed supply for forestry nurseries, leading to serious reforestation and propagation challenges.

Control measures. Management of this pest relies on both preventive and curative strategies:

• Fumigation of seed stocks using approved chemical agents to kill internal larvae.
• Harvesting pods as early as possible to reduce the window of opportunity for egg-laying.
• Implementing strict sanitation protocols in storage facilities.
• Application of selective insecticides during the blooming phase to suppress adult populations.