Oak: California gallfly categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:34 “Oak apples” caused by California gallflyPhoto by: R.S. Byther Biology The gall of this cynipid wasp larvae is the largest and most conspicuous of the galls on oak, achieving a diameter of one to four inches. It is a twig […]
Oak: Jumping oak gall categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:35 Jumping oak galls on leaves caused by an insectPhoto by: A.L. Antonelli Biology Jumping oak galls cause small yellow spots on the upper surface of infested leaves. On the underside of the leaves are tiny seedlike galls. These appear […]
Oak: Leaf galls categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:36 Jumping oak galls on leaves caused by an insectPhoto by: A.L. Antonelli Biology Leaf galls are caused by the feeding of several species of oak gall wasp larvae. Typical galls are enlarged or swollen plant tissues. These may assume several […]
Oak: Oak leaf phylloxera categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:40 Oak leaf phylloxera damagePhoto by: A.L. Antonelli Biology The oak leaf phylloxera is a pest of growing importance in the Pacific Northwest. It’s believed to have come from Europe in the early 1960’s. It is a yellowish orange homopteran […]
Oak: Oak ribbed casemaker categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:41 Oak ribbed casemakerPhoto by: A.L. Antonelli Biology Oak ribbed casemaker larvae mine and skeletonize leaf tissues. Young larvae feed inside leaves, chewing away tissues and leaving a linear mine. Older larvae feed on the underside of leaves, leaving only […]
Oak: Oak treehoppers categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:42 Oak treehoppersPhoto by: A.L. Antonelli Biology The oak treehopper belongs to a family of plant lice distantly related to aphids. However, they are fairly hard-bodied, and the adults bear a pointed hood on the back behind the head. They are […]
Oak: Pit scale categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:43 Oak pit scalePhoto by: A.L. Antonelli Biology Pit scales of oak may be brown, gold, or greenish in color. They feed on twigs and small branches, with young wood most commonly infested. Pit scale feeding causes the tissue of the […]
Oak: Stem galls categories: Oak Oak Insects Ornamental trees Ornamentals last review date: 2025-06-30 10:44 Oak stem gallsPhoto by: A.L. Antonelli Biology Stem galls are caused by the feeding of several species of oak gall wasp larvae. Typical galls are enlarged or swollen. Galls associated with oak stems are often smooth and round, but may […]
Oak: Anthracnose categories: Oak Oak Diseases Ornamental trees Ornamentals last review date: 2025-06-30 10:51 Biology Oak anthracnose is a fungal disease of leaves and twigs of many species of oak. Typical symptoms include the presence of small to large brown lesions on the leaves, usually along the midrib or main veins. Half or more of […]
Oak: Armillaria root rot categories: Oak Oak Diseases Ornamental trees Ornamentals last review date: 2025-06-30 10:55 White fungal mat of Armillaria root rot infecting trunkPhoto by: C.R. Foss Biology Armillaria root rot is a fungal disease often found in newly cleared soils or soils which have been flooded. Above ground symptoms typically include production of […]