Cottonwood borer

Taxonomic position: Plectrodera scalator is a member of the order Coleoptera and the family Cerambycidae, commonly known as long-horned beetles. This species is a significant wood-boring pest that primarily targets specific deciduous trees in North American landscapes and commercial forest plantations.

Host plants: The pest is highly specialized, feeding exclusively on trees within the Salicaceae family. The primary hosts include cottonwood (Populus deltoides) and various species of willow (Salix). These insects are particularly devastating to young plantations where they can compromise the entire root system of the trees.

Biology and life cycle: The life cycle typically ranges from one to two years. Adult beetles emerge during the summer months, feeding on the bark and foliage of succulent shoots. Females deposit eggs into slits made in the bark near the soil line. Upon hatching, the larvae bore into the roots and the base of the trunk, constructing large galleries that significantly weaken the tree structure.

• Destruction of cambium and wood tissue at the tree base.
• Increased risk of tree blow-over or mechanical failure in high winds.
• Stunted growth and yellowing of foliage due to interrupted vascular flow.
• Potential mortality of saplings due to complete girdling of the stem.

Control measures: Management of the cottonwood borer is challenging due to the internal feeding habit of the larvae. Cultural control, such as removing and destroying infested trees, is a primary strategy. Chemical control is limited to applying insecticides on the trunks during the adult emergence period. Maintaining tree vigor through proper irrigation and fertilization is essential for integrated pest management.