Oak: Oak treehoppers categories: Oak Oak Insects Ornamental trees Ornamentals revision date: 2022-11-25 12:53 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 quite […]
Oak: Pit scale categories: Oak Oak Insects Ornamental trees Ornamentals revision date: 2024-06-05 02:04 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 twig […]
Oak: Stem galls categories: Oak Oak Insects Ornamental trees Ornamentals revision date: 2022-11-25 12:39 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 be […]
Oak: Anthracnose categories: Oak Oak Diseases Ornamental trees Ornamentals revision date: 2024-06-05 02:07 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 a […]
Oak: Armillaria root rot categories: Oak Oak Diseases Ornamental trees Ornamentals revision date: 2022-11-25 12:24 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 smaller-than-normal leaves, […]
Oak: Leaf scorch categories: Oak Oak Diseases Ornamental trees Ornamentals revision date: 2022-11-25 12:20 Oak leaf with leaf scorch symptomsPhoto by: B.M. Johnson Biology Leaf scorch has many possible causes. Plants that are under stress (such as from drought or heat) may not provide sufficient water to leaves, causing the edges to turn bronze, then […]
Oak: Mistletoe categories: Oak Oak Diseases Ornamental trees Ornamentals revision date: 2022-11-25 12:16 Oak mistletoe (a true mistletoe)Photo by: J.W. Pscheidt Biology Mistletoe is a parasitic plant which grows on the branches of a host tree. True mistletoe, found on oaks and a few other hardwood species, does not grow on conifers. It is spread […]
Oak: Western oak looper categories: Oak Oak Insects Ornamental trees Ornamentals revision date: 2023-04-12 12:00 Looper crawling on edge of rhododendron leafPhoto by: S.J. Collman Biology The Western oak looper feeds mainly on the foliage of the Oregon white (or Garry) oak (Quercus garryana). Mature larvae of the Western oak looper are about 1″ long […]
Oak: Sudden oak death categories: Oak Oak Diseases Ornamental trees Ornamentals revision date: 2022-11-25 12:00 P. ramorum symptoms on tanoak leavesPhoto by: M. Elliott Biology Sudden oak death (SOD) is the common name for a disease of oaks (Quercus spp.) and tanoak (Lithocarpus densiflorus) caused by Phytophthora ramorum, a previously unknown and exotic plant pathogen. […]
Mountain Ash: Fire blight categories: Mountain Ash Mountain Ash Diseases Ornamental trees Ornamentals revision date: 2022-11-25 11:52 Cotoneaster fire blightPhoto by: R. Maleike Biology Fire blight is a bacterial infection of shoots which enters the plant through blossoms, vigorously growing shoot tips, young leaves, and wounds. Blossom clusters appear blighted. Shoots suddenly wilt, turn black […]
Mountain Ash: Nectria canker categories: Mountain Ash Mountain Ash Diseases Ornamental trees Ornamentals revision date: 2022-11-25 11:47 Nectria canker fruiting bodiesPhoto by: R.S. Byther Biology Nectria canker is a fungal disease often found on twigs and branches that have been weakened by drought, frost damage, insect damage, or other diseases. Cankers are initially distinguished by […]
Mountain Ash: Aphids categories: Mountain Ash Mountain Ash Insects Ornamental trees Ornamentals revision date: 2024-06-05 08:29 Aphid colonyPhoto by: Unknown Biology Aphids are small, soft-bodied insects that typically feed near the tip of growing shoots. Their feeding may deform leaves (curling, distortion) and stunt terminal growth. Aphids range in size up to 1/8″ long and […]
Mountain Ash: Ash borer categories: Mountain Ash Mountain Ash Insects Ornamental trees Ornamentals revision date: 2022-11-25 11:41 ash borer pupal ‘skeleton’Photo by: A.L. Antonelli Biology The ash borer, also known as the lilac borer, is a member of the clearwing moth family. The adults of many clearwing moths mimic yellowjackets or paper wasps. The larvae […]
Mountain Ash: Leaf blister mite categories: Mountain Ash Mountain Ash Insects Ornamental trees Ornamentals revision date: 2022-11-25 11:37 Pear leaf blister mite damage on mountain ashPhoto by: R.S. Byther Biology The leaf blister mite is a very tiny white, sausage-shaped eriophyid mite. They are seldom visible to the unaided eye. Eriophyid mite feeding on the […]
Mountain Ash: Mountain ash sawfly categories: Mountain Ash Insects Ornamental trees Ornamentals revision date: 2024-06-05 10:25 Mountain ash sawfly larvae feeding on leafPhoto by: S. Katovich, USDA Forest Service, bugwood.org Biology Mountain ash sawfly is a relatively new pest to western Washington. First reported in 2009, the larval stage of this insect feeds on leaves […]
Maple: Anthracnose categories: Maple Maple Diseases Ornamental trees Ornamentals revision date: 2022-11-25 10:14 Maple anthracnosePhoto by: R.S. Byther Biology Maple anthracnose is a fungal disease affecting leaves and sometimes twigs. Infected leaves develop discrete brown spots and/or blotches, often at leaf tips and often associated with the main or secondary veins. Japanese maples tend to […]
Maple: Bacterial leaf spot and dieback categories: Maple Maple Diseases Ornamental trees Ornamentals revision date: 2022-12-05 12:00 Pseudomonas leaf spot on maplePhoto by: R.S. Byther Biology Bacterial leaf spot and dieback is caused by the same bacterium which causes bacterial blight of lilacs and many other woody ornamentals. Symptoms include leaf spots, blackening of leaf […]
Maple: Fasciation categories: Maple Maple Diseases Ornamental trees Ornamentals revision date: 2022-11-25 10:01 Fasciation showing a flattened, twisted, ribbed stemPhoto by: R.S. Byther Biology Fasciation is a plant deformity which results in abnormally flattened stems. It is the result of a mutation in the growing point of the stem and is not a disease. Instead […]
Maple: Leaf scorch categories: Maple Maple Diseases Ornamental trees Ornamentals revision date: 2022-11-25 09:57 Leaf scorch on maplePhoto by: R.S. Byther Biology Leaf scorch on maple has many possible causes. Plants that are under stress, such as drought or heat stress, may not provide sufficient water to the leaf margins, causing the edges of the […]
Maple: Nectria canker categories: Maple Maple Diseases Ornamental trees Ornamentals revision date: 2022-11-25 09:54 Tubercularia canker fruiting bodiesPhoto by: R.S. Byther Biology Nectria is a fungal infection which often attacks via wounds and forms cankers on twigs, branches, and trunks. The cankers are often sunken areas that develop conspicuous yellow to orange-red fungal fruiting bodies […]