WOOD BORING INSECTS ATTACKING ORNAMENTALS

Bark Beetles

Nearly all bark beetles (Family: Scolytidae) bore into bark or wood, both as larvae and as adults. The wood engravers form mines in the bark and the cambium. The ambrosia beetles burrow into the heartwood and feed on fungi in the galleries. Bark beetles are very common and usually attack weakened, dying, dead, or recently cut trees. Some attack healthy trees.

Long-horned Beetles

Most of the long-horned beetles (Family: Cerambycidae) are elongate and cylindrical with long antennae. The larvae are wood boring and are destructive to shade, forest, and fruit trees, and to freshly cut logs. The adults lay their eggs in crevices in the bark and the larvae bore into the wood. Different species attack different types of trees and shrubs. A few species attack living trees, but most prefer weakened and dying trees or branches.

Metallic Wood-boring Beetles

The metallic wood-boring beetles (Family: Buprestidae) attack either living trees in a state of decline, or newly cut logs. Eggs are usually laid in crevices in the bark. The emerging larvae tunnel under the bark and eventually bore into the wood. The galleries under the bark are often winding and filled with frass. The adult beetles are often metallic in colour.

Weevils

Poplar-and-willow borer

Some weevils (Family: Curculionidae) are known to infest the trunks and larger limbs of trees. Examples are the poplar-and-willow borer (Cryptorhynchus lapathi) and the white pine weevil (Pissodes strobi).

Clear-winged Moths

Clear-winged moths (Family: Sesiidae) resemble wasps. Many species are brightly coloured, and most of them are active during the day. The larvae bore in the roots, stems, canes, or trunks of plants or trees. The maple borer damages both the trunk and limbs of hard and soft maples.

Carpenter Moths

Carpenter moths (Family: Cossidae) are wood-boring in the larval stage. The young larvae mine in the cambium and later enter the heartwood. Complete development takes 3 years. The adults appear in May-June. Injury is usually confined to the heartwood of mature trees.

Horntail Wasps

Horntails (Family: Siricidae) are large insects, usually 25 mm or more in length. The larvae burrow in maple, elm, beech and other trees, but are seldom sufficiently numerous to do a great deal of damage.

Leaf-cutter Bees

The leaf-cutter bee (Family: Megachilidae) excavates tunnels in solid wood, in soil, or in protected places. The cells are thimble shaped and contain one egg. The common name of these bees is derived from the fact that in many species, the nest cells are lined with pieces cut from leaves.

Carpenter Ants

Carpenter ants (Family: Formicidae) often nest in decaying stumps, logs, or declining trees. Winged reproductives make their entrance through knotholes or abrasions in the bark near the base of mature trees. Their activities are often restricted to the heartwood.