ForesTree - A Guide to Tree Health

Pest and Disease Information

California Black Oak
  • Quercus kelloggii - Resistant to Verticillium. Susceptible to Goldspotted Oak Borer, Insect Galls, Carpenterworm, California Oak Moth, Pacific Oak Teig Girdler, Oak Pit Scales, Gall Wasp and Scales, Sudden Oak Death, Anthracnose, Oak Root Rot, Brown Rot, Annosus Root Disease, Mistletoe, Powdery Mildew and Root Rot. Additional and expanded information listed below.

  • For further tree information:
       SelecTree (1244) | Silvics of North America
8 Records Found
Disease or Pest NameDescription of Disease or Pest

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...

Prionoxystus robiniae

Prionoxystus_robiniaeThe carpenterworm attacks small and large trees in the trunk or limbs. It prefers open grown trees. The adult is a large grayish moth, which appears in the early summer. Eggs are deposited in bark crev...

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...

Oak pit scales
Asterolecanium minus

Asterolecanium_minusOak pit scales feed on oak twigs causing ring-shaped depressions on the bark. Death of twigs and distorted terminal growth may result from heavy infestations. Mature scales appear as brown, gold, or gree...