Laurel: Carnation tortrix categories: Laurel Laurel Insects Ornamental trees Ornamentals revision date: 2023-04-12 12:00 Carnation tortrix, yellow-green caterpillarPhoto by: A.L. Antonelli Biology Portuguese laurel (Prunus lusitanica) is sometimes infested with the larvae of the carnation tortrix, a small bell-shaped brown moth with reddish underwings and dark bands on the upper wings. The larvae feed by […]
Laurel: Physiological shothole categories: Laurel Laurel Diseases Ornamental trees Ornamentals revision date: 2022-11-23 01:29 Laurel physiological shotholePhoto by: R.S. Byther Biology Shothole symptoms resulting from cultural or environmental stress are commonly observed on laurels. Research has failed to identify what specific stress is responsible. Symptoms are first observed as necrotic leaf spots with circular to […]
Horsechestnut: Leaf scorch categories: Horsechestnut Horsechestnut Diseases Ornamental trees Ornamentals revision date: 2022-11-23 01:15 Leaf scorch on horsechestnutPhoto by: R.S. Byther Biology Leaf scorch often occurs on a variety of trees (including horse-chestnut) in central and eastern Washington, and sometimes western Washington during the summer. It usually arises after periods of unfavorable weather or stress, […]
Honey locust: Honeylocust pod gall midge categories: Honey Locust Insects Ornamental trees Ornamentals revision date: 2024-06-05 10:25 Honey locust pod gall midgePhoto by: R.S. Byther Biology The honey locust pod gall midge is a tiny orange gnat that lays its eggs on new foliage in the spring. The small pinkish or yellow-white maggots feed on […]
Honey locust: Honeylocust canker categories: Honey Locust Honey Locust Diseases Ornamental trees Ornamentals revision date: 2022-11-23 12:58 Large canker on honey locustPhoto by: R.S. Byther Biology Several fungi are responsible for cankers on honey locust in the Pacific Northwest. One problem, coral spot or Nectria canker, can result in sudden wilting or failure of infected […]
Honey locust: Powdery mildew categories: Honey Locust Honey Locust Diseases Ornamental trees Ornamentals revision date: 2022-11-23 12:53 Biology Powdery mildew on honey locust (Gleditsia triacanthos) produces typical symptoms of powdery mildew infections. Leaves and sometimes young shoots are covered with a powdery, gray-white growth. This most often appears in summer and gradually increases throughout the […]
Honey locust: Locust borer categories: Honey Locust Honey Locust Insects Ornamental trees Ornamentals revision date: 2022-11-23 12:51 Honey Locust borer adultPhoto by: Unknown Biology Black locust (Robinia pseudoacacia) may be infested by the larvae of a boring beetle. Eggs laid in the fall on the bark hatch into larvae which burrow beneath the bark and […]
Hawthorn: Apple-and-thorn skeletonizer categories: Hawthorn Hawthorn Insects Ornamental trees Ornamentals revision date: 2024-06-07 06:33 Apple-and-thorn skeletonizer caterpillar feeding on leafPhoto by: A.L. Antonelli Biology The adult of the apple-and-thorn skeletonizer is a small dark-brown moth. It overwinters as an adult, laying eggs in the spring. The caterpillars are yellow-green in color with black spots and […]
Hawthorn: Hawthorn aphid categories: Hawthorn Hawthorn Insects Ornamental trees Ornamentals revision date: 2024-06-05 02:04 Green peach aphid closeupPhoto by: Unknown Biology Hawthorn aphids are yellow-green to pinkish, soft-bodied insects typically found on the leaves in the spring. Aphid feeding causes young leaves to curl tightly and turn purplish. Older leaves are crinkled and deformed. Feeding […]
Hawthorn: Pear slug categories: Hawthorn Hawthorn Insects Ornamental trees Ornamentals revision date: 2024-06-05 08:28 Pear slug and damaged leaf from feedingPhoto by: R.D. Akre Biology Pear slugs, or pear sawflies, are insect larvae which resemble a small greenish or black slug. They are typically 1/4″ to 1/2″ long, tadpole-shaped. and produce large amounts of slime. […]
Hawthorn: Scale insects categories: Hawthorn Insects Ornamental trees Ornamentals revision date: 2024-06-05 02:04 Lecanium scales on twigPhoto by: R.S. Byther Biology Several species of scales may be found on hawthorn. In general, scales are approximately 1/16″ to 1/8″ in diameter, dull or shiny, and grayish to dark in color. They are typically found on the […]
Hawthorn: Fire blight categories: Hawthorn Hawthorn Diseases Ornamental trees Ornamentals revision date: 2022-11-22 03:22 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 and die back, presenting a “scorched” appearance. Purplish cankers […]
Hawthorn: Leaf spot categories: Hawthorn Hawthorn Diseases Ornamental trees Ornamentals revision date: 2024-06-05 02:07 Hawthorn leaf spotPhoto by: R.S. Byther Biology Leaf spot is a fungal disease which can infect hawthorn, photinia, pear, pyracantha, crabapple, and related species. Initial infections are small reddish-brown to grayish spots on the upper or lower leaf surface. The spots […]
Hawthorn: Rust categories: Hawthorn Hawthorn Diseases Ornamental trees Ornamentals revision date: 2024-06-05 02:07 Rust pustules on underside of serviceberry leaf and on petiolePhoto by: R.S. Byther Biology Rust is a fungal disease typically infecting leaves of hawthorn (occasionally also apple and crabapple). It may also be found on green stems and fruit. Initial symptoms are […]
Hawthorn: Scab categories: Hawthorn Hawthorn Diseases Ornamental trees Ornamentals revision date: 2024-06-05 02:07 Apple scab on leaves and young fruitPhoto by: R.S. Byther Biology Scab of hawthorn is caused by the same fungus that causes scab on apple and crabapple. The disease infects during wet weather in the spring and initially causes small pale, watersoaked […]
Hawthorn: Spider mites categories: Hawthorn Hawthorn Insects Ornamental trees Ornamentals revision date: 2024-06-05 08:28 Spider mites under microscopePhoto by: L.K. Tanigoshi Biology Spider mites are tiny, eight-legged and variably colored from yellow or green to red or brown. When viewed through a hand lens, they appear as tiny moving dots. Spider mites typically feed on […]
Elm: Aphids categories: Elm Elm Insects Ornamental trees Ornamentals revision date: 2024-06-05 02:04 Elm woolly aphidPhoto by: A.L. Antonelli Biology Aphids are soft-bodied, pear-shaped insects that feed on the leaves. They are yellowish to green in color and approximately 1/16″ long. Aphids often produce honeydew, a sweet, sticky substance which can develop a dark growth […]
Elm: Bark beetles categories: Elm Elm Insects Ornamentals revision date: 2022-11-22 02:27 Bark beetle larval galleriesPhoto by: A.L. Antonelli Biology Elm bark beetles are about 1/8″ long and may be shiny brown or black. Adults, larvae, or pupae overwinter under bark. Adult beetles emerge in the spring (around May), leaving tiny “shotholes” in the bark. […]
Elm: Carpenterworm categories: Elm Elm Insects Ornamental trees Ornamentals revision date: 2022-11-22 02:15 Carpenterworm larval minePhoto by: Unknown Biology Carpenterworms are the larvae of a mottled gray and black moth. The caterpillars are white to pinkish-red with a dark head and 1″ to 3″ long when mature. They bore in the trunk and main branches […]
Elm: Elm leaf beetle categories: Elm Elm Insects Ornamental trees Ornamentals revision date: 2023-04-04 12:00 Elm leaf beetlesPhoto by: Unknown Biology Elm leaf beetles feed on the leaves both as larvae and as adults. The larvae appear in late spring (typically May-June) from eggs laid by overwintering adults. The 1/4″ larvae are greenish or yellow […]