Conifer Beetle.

Several species of bark beetle including Southern Pine Beetle, Black Turpentine Beetle, Mountain Pine Beetle, Western Pine Beetle, and Spruce Beetle (all Dendroctonus species), and Ips Engraver Beetle, are known to attack and kill conifers such as pines and/or spruce.

These beetles bore into the tree in large numbers and construct egg galleries in the cambium layer. This disrupts nutrient and water movement, thus killing the tree. Several of these species also introduce a fungus, known as blue stain, which aids in killing a tree by clogging its vascular system.

Emerald Ash Borer.

The Emerald Ash Borer (EAB) is an invasive pest introduced from Asia that attacks ash trees.

This metallic wood boring beetle was found in Detroit, Michigan and Ontario, Canada in 2002, and has continued to spread into neighboring states and eventually across the U.S. and Canada. The adult is a small, metallic green beetle only 10-15 mm in length and about 3 mm in width. The larvae live under the bark of the tree and feed in the vascular cambium. The adults typically emerge around June, leaving D-shaped exit holes in the bark. This ash tree insect briefly feeds in the canopy before reproducing and laying eggs in the twigs and branches.

Red Gum Lerp Psylid

The red gum lerp psyllid (RGLP) (Glycaspis brimblecombei) is a foliar pest on red gum eucalyptus trees (Eucalyptus camaldulensis).

Like Eucalyptus trees, the RGLP is native to Australia. RGLP is a plant-juice sucking homopteran in the family Psyllidae. The nymphs form a protective covering of crystallized honeydew called a lerp, which protects the insects from both predators and insecticidal foliar sprays. Excess honey dew results in the growth of sooty mold. The RGLP is responsible for extensive defoliation of Red Gum Eucalyptus trees. Heavy infestations result in reduced tree health, decline and ultimately, tree loss.

Oak Worms

There are several caterpillars that feed on oaks including the California oak worm and tussock moth.

Each of these caterpillars feed on oak leaves. Oak worms are smooth, small, yellow-green caterpillars with brown heads and dark stripes down their sides. They can range from 1/10 to 1 inch in length throughout their development. Tussock moth larvae are very distinctly hairy with three prominent creamcolored dots towards the head capsule.

In California, Oak Worm is most commonly found on coastal live oak in San Francisco, Monterey Bay, Santa Barbara, and other areas close to water sources. Tussock moth is common in San Francisco but can also be found along the Central Coast

Bronze Birch Borer

The Bronze Birch Borer is a wood boring beetle, common across the northern half of the United States, which attacks all birch species.

The adult is a copper/bronze colored slender beetle. The larvae, which does the damage, are unseen, feeding on the vascular tissue under the bark. The Bronze Birch Borer typically attacks trees which are already stressed or in decline. A birch infested with Bronze Birch Borer will start showing dieback in the crown, increasing in severity as the infestation continues, often leading to death of the tree. In later stages of infestation, the trunk will show D-shaped, rust-stained exit holes and may also have swollen extrusions under the bark where the tree tried to grow over larval galleries