How to Manage Pests

Pests in Gardens and Landscapes

Roundheaded (Longhorned) borers

Adult roundheaded borers are medium to large, elongate, cylindrical beetles that are often brightly colored. They have long antennae, so are sometimes called longhorned borers or beetles. One common species, the poplar borer (Saperda calcarata) attacks aspen, cottonwood, poplar, and willow. Information about the eucalyptus longhorned borer, shown at right, is detailed in the eucalyptus longhorned borer Pest Note.

Life cycle


Holes in bark and stains or oozing liquid on limbs or trunks are common symptoms of damage by roundheaded borers. Foliage may discolor and wilt, limbs may die back, and branches or entire plants may be killed. However, roundheaded borers attack mostly damaged or dying plants; vigorous trees are rarely attacked.


Plant species that are well adapted to each location and provide them with proper cultural care. Protect trees from injuries. Remove dead limbs or trees promptly and do not store freshly cut wood near trees; beetles may emerge and attack nearby plants. Pesticide applications to bark have not been found to be effective.

Eucalyptus longhorned borer
Adult eucalyptus longhorned borer
Eucalyptus longhorned borer tunnels
Eucalyptus longhorned borer tunnels under bark

Bleeding branch borer and old gall
Bleeding branch and old gall caused by popular borer

Statewide IPM Program, Agriculture and Natural Resources, University of California
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