Emerald thuja borer

Systematic position: Lamprodila mirifica belongs to the order Coleoptera and the family Buprestidae. These metallic wood-boring beetles are significant pests known for their ability to colonize and destroy healthy or stressed woody plants through their larval activities within the vascular tissues.

Host plants: The pest primarily targets members of the Cupressaceae family, specifically focusing on Thuja (arborvitae), Juniperus (juniper), and Chamaecyparis (false cypress). It has become a significant problem in nursery production and residential landscapes across its range.

Biology and life cycle: The life cycle involves egg-laying on the bark, followed by larval development under the bark layers. Larvae tunnel into the phloem and cambium layers, feeding throughout the growing season. The insect typically completes its life cycle within one to two years, depending on regional temperature and host tree condition.

Nature of damage: Larval feeding disrupts the transport of water and nutrients, leading to yellowing, dieback of branches, and eventually tree death. Typical signs include D-shaped exit holes on the trunk and the presence of frass within galleries under the bark, which can often be detected only after the tree starts to decline.

Protection measures: Management includes the removal and destruction of infested wood to reduce population levels. Systemic insecticides can be used preventively during the adult emergence window. Maintaining healthy tree vigor through proper watering and fertilization is essential to discourage adult females from selecting trees for oviposition.