Kinnikinnick: Leaf spot categories: Kinnikinnick Kinnikinnick Diseases Ornamentals Shrubs revision date: 2022-12-03 12:00 Kinnikinnick leaf spotPhoto by: R.S. Byther Biology Leaf spot is a fungal disease. Symptoms include development of brown, necrotic spots on leaves. The fungus most likely overwinters on infected leaves and possibly on twigs. The disease is favored by cool, wet conditions […]
Kinnikinnick: Rust categories: Kinnikinnick Kinnikinnick Diseases Ornamentals Shrubs revision date: 2022-12-03 12:00 Rust pustules on underside of serviceberry leaf and on petiolePhoto by: R.S. Byther Biology Kinnikinnick rust is a fungal disease of the leaves which requires an alternate host (spruce) to complete its life cycle. Symptoms of rust on kinnikinnick are seen in late […]
Kinnikinnick: Aphid (Manzanita leafgall aphid) categories: Kinnikinnick Kinnikinnick Insects Ornamentals Shrubs revision date: 2024-06-05 02:05 Kinnikinnick leafgall aphidPhoto by: R.S. Byther Biology The manzanita leafgall aphid feeds on the leaves of kinnikinnick and other manzanita species (Arctostaphylos spp.). The aphids are grayish or greenish in color and prefer new growth. Aphid feeding causes the leaves […]
Hypericum: Rust categories: Hypericum Hypericum Diseases Ornamentals Shrubs revision date: 2022-12-03 12:00 Hypericum rust: upper leaf surfacePhoto by: R.S. Byther Biology Hypericum rust in Washington is caused by a rust fungus that does not have an alternate host. Yellow, red, or brown spots are observed on leaf surfaces. In spring and early summer, powdery orange […]
Hydrangea: Failure to bloom categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Biology Improper pruning is the most common reason hydrangeas fail to bloom. Both bigleaf (Hydrangea macrophylla) and oakleaf (H. quercifolia) hydrangeas produce their flowers on the previous year’s growth. If these stems are removed, new growth may fail to produce flowers […]
Hydrangea: Fungal leaf spots categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Mycosphaerella leaf spot, www.forestryimages.orgPhoto by: B.J. Jacobsen, NCSU Biology Several fungal diseases cause spotting of leaves on hydrangeas. Symptoms may include brown, black, or gray spots or angular blotches. These may be surrounded by a reddish or purple halo. Spotting may […]
Hydrangea: Hail damage categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Hail damage to hydrangea leafPhoto by: J. Glass Biology Damage to plants depends on size of the hailstones and intensity of the storm. Minor damage may not show immediately, but may appear days or weeks later as small whitish scars or spots […]
Hydrangea: Herbicide damage categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Biology Symptoms of herbicide damage may be confused with damage from insects, disease, or cultural problems. Specific injury symptoms vary depending on degree of exposure, product used, and plant species. Damage may not appear immediately, and plants may exhibit symptoms for more […]
Hydrangea: Leaf scorch categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Leaf scorch on hydrangeaPhoto by: J. Glass Biology Leaf scorch on hydrangea is a common physiological problem. Typical symptoms include yellowing leaves, or irregular dry, brown blotches. Leaf tips and margins may turn brown, as well. Severely damaged leaves may drop from […]
Hydrangea: Marginal leaf necrosis categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 drought damage to H. macrophyllaPhoto by: R. Maleike Biology Browning and dieback of leaf margins and tips can be a symptom of several problems that restrict water flow to the leaves. Drought, excess heat, excess sunlight, overfertilization, and herbicide injury are […]
Vertebrate: Sapsucker damage categories: Vertebrates revision date: 2022-12-28 12:00 Sapsucker damage on birchPhoto by: C.R. Foss Biology Rows of horizontally oriented holes in trunks and branches of various types of trees are typical feeding sites for sapsuckers (woodpeckers). Mild to moderate damage usually has little long-term impact on the health of the tree. Severe damage […]
Hydrangea: Powdery mildew categories: Hydrangea Hydrangea Diseases Ornamentals Shrubs revision date: 2024-06-05 10:24 Powdery mildew on hydrangeaPhoto by: Dept. of Plant Pathology, NCSU Biology Powdery mildew is a fungal disease affecting leaves, young shoots, and flowers. White to grayish, powdery fungal growth develops on the top of the leaf and may also appear on tender […]
Holly: Boron deficiency categories: Holly Holly Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Necrotic spotting on leaves from boron deficiency Photo by: R.S. Byther Biology Boron deficiency in holly is characterized by the appearance of spots on the leaves. The spots initially are red to purple and irregularly shaped on the upper surface. They appear […]
Holly: Green algae categories: Holly Holly Diseases Ornamentals Shrubs revision date: 2022-12-05 12:00 Green algae on hollyPhoto by: B.M. Johnson Biology Green algae grows on the surface only of leaves, twigs, and trunks. Wet, humid weather favors development of these microscopic, moisture-loving, primitive plants. The colonized holly is not harmed unless sufficient algal growth develops […]
Holly: Phytophthora leaf & twig blight categories: Holly Holly Diseases Ornamentals Shrubs revision date: 2024-06-05 02:07 Holly Phytophthora leaf and twig blightPhoto by: J.W. Pscheidt Biology Leaf and twig blight of holly is caused by a different Phytophthora species than is associated with root rots. Symptoms first appear in the fall and winter during wet, […]
Holly: Red leaf spotting categories: Holly Holly Diseases Ornamentals Shrubs revision date: 2022-12-02 12:00 Holly red leaf spottingPhoto by: J.W. Pscheidt Biology Red leaf spotting of holly is a general category which includes physical or pesticide damage, nutritional deficiency, and disease symptoms. Damage from the holly’s own spines can cause leaves to develop red or […]
Holly: Brown soft scale categories: Holly Holly Insects Ornamentals Shrubs revision date: 2024-06-05 08:28 Brown soft scalesPhoto by: R.S. Byther Biology Brown soft scales are yellowish to dark brown insects (adults are usually darker) up to approximately 1/8″ in diameter. They are found mainly on the underside of leaves or on green twigs. Soft scales […]
Holly: Cottony camellia scale categories: Holly Holly Insects Ornamentals Shrubs revision date: 2024-06-05 08:28 Cottony camellia scale on holly leavesPhoto by: A.L. Antonelli Biology The cottony camellia scale is a flat brownish or yellowish insect about 1/8″ in diameter. The scales overwinter on twigs or evergreen leaves. In the spring, the adult females lay cottony […]
Holly: Holly bud moth categories: Holly Holly Insects Ornamentals Shrubs revision date: 2024-06-05 02:07 Holly bud moth larvae damagePhoto by: Unknown Biology The adult holly bud moth is a mottled brown and black insect with a wingspan of approximately 1/2″. Overwintering eggs hatch in the spring. The larvae begin feeding on buds but soon move […]
Holly: Holly leafminer categories: Holly Holly Insects Ornamentals Shrubs revision date: 2022-12-05 12:00 Holly leafminer trailsPhoto by: R.S. Byther Biology The holly leafminer feeds on English (Ilex aquifolium), American (I. opaca) and Japanese (I. crenata) hollies, tiny green blisters on the lower leaf surface often indicate sites where the females deposited eggs. Characteristic damage by […]