ForesTree - A Guide to Tree Health

Pest and Disease Information

Canyon Live Oak
  • Quercus chrysolepis - Resistant to Verticillium. Susceptible to Invasive Shot Hole Borer, Goldspotted Oak Borer, Aphids, Caterpillars, Coddling Moths, Insect Galls, California Oak Moth, Pacific Oak Teig Girdler and White Fly, Sudden Oak Death, Crown Rot, Mistletoe, Armillaria and Root Rot. Additional and expanded information listed below.

  • For further tree information:
       SelecTree (1232) | Silvics of North America
9 Records Found
Disease or Pest NameDescription of Disease or Pest

Oak root fungus
Armillaria mellea

Armillaria_melleaArmillaria cases reduced terminal growth and general decline in affected plants, As the Armillaria advances dieback of twigs and branches (most apparent in hardwoods) can occur. Crown symptoms include chl...

Powdery Mildew
Microsphaera alni

Powdery mildew may occur on any green plant tissue or on flowers and fruits. Light colored mats of fungal growth often appear on infected leaves. Infected leaves may drop prematurely and leaves and shoot...

Sudden Oak Death
Phytophthora ramorum

AerialPhytophthora ramorum causes two types of symptoms on affected plants. In some it causes bleeding cankers on the mainstem with red-brown exudate. Zone lines are present around diseased tissue when bark is ...

True Mistletoe
Phoradendron villosum

phoradendron_villosumTrue mistletoe is an evergreen parasitic plant with developed stems and leaves. The infection causes swollen branches and brooming. Most infections start in the upper crown of the tree, since the plant i...

California oakworm
Phryganidia californica

phryganidia_californicaCalifornia oakworm is an important defoliating pest of ornamental coast live oak. Most years it is of little concern, but some years the damage is extensive. California oakworm seldom kills trees, but it...

Fruittree leafroller
Archips argyrospila

moth"Fruittree leafroller can be a serious pest throughout California. It occurs on a very large number of ornamental trees and is particularly damaging to deciduous and live oaks. Even if completely defoliate...

Gall wasp

Cynipidae_gallHundreds of species of gall wasps occur in the oaks in California. The female wasp deposits her egg in the plant tissue and the plant produces the gall around the developing wasp. They generally do not d...

Gold-spotted Oak Borer
Agrilus auroguttatus

Agrilus_auroguttatusAgrilus auroguttatus (formerly called Agrilus coxalis) is killing oak trees by the thousands in Southern California, according to a report by the U.S. Forest Service. Forest Service entomologists previousl...

Pacific oak twig girdler
Agrilus angelicus

Pacific oak twig girdler is rated the number one pest of ornamental oaks in Southern California, especially live oaks. Trees weakened by drought are most affected. Adult beetles are brownish copper and l...