This article discusses three common roundheaded borers. Larvae are little, white, cylindrical grubs with no legs.
The wood mining and exit holes are often visible, and the exact borer species that destroyed the tree cannot be identified.
The juniper borer and black-horned juniper borer in trunks and branches and the juniper twig pruner in twigs and tiny branches have been confirmed to occur in the Rocky Mountain Region.
Damage might be severe before symptoms appear. Frequently, a considerable area of the tree, or the entire tree, dies before the insects’ escape holes are discovered.
Host plants: Junipers
Damage caused by Blackhorned Juniper Borer:
Damage might be severe before symptoms appear. Frequently, a considerable area of the tree, or the entire tree, dies before the insects’ escape holes are discovered. Girdling wounds caused by larval feeding damage branches or whole trees. Before evident signs appear, damage may accumulate gradually over several years.
Life history and Habits:
The life cycles of different animals differ. The larvae of the black-horned juniper borer (Callidium texanum) dig beneath the bark, creating broad, wavy tunnels that score the exterior sapwood. Older larvae dig oval tunnels deep into the wood and spend the winter inside afflicted branches or boles. Adults emerge throughout the year during the warm months. Each year, one generation is born. Adult beetles have small horns for cerambycids, are dark blue or black, and are less than 1/2 inch (1 cm) long. Larvae of the black-horned juniper borer (Callidium texanum) burrow beneath the bark, leaving broad, wavy galleries that score the exterior sapwood. Older larvae dig oval tunnels deep into the wood and spend the winter inside afflicted branches or boles. Adults emerge throughout the hotter months of the year.
