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Plant NameTypeDescription 
AnthracnoseDogwoodDiseaseDogwood anthracnose is a fungal disease of leaves and twigs. It is found mainly on the native dogwoods, especially Pacific dogwood, but can also infect some ornamental dogwoods. The leaves display small to large irregular brown blotches or occasionally purple-edged spots. The blotches are often at the tip of the leaf, triangular, and centered on the main vein. Infected leaves may drop before normal leaf fall. Twigs have sunken spots which are brown with purple edges. Dieback of infected twigs is common, with dead leaves remaining on the twig. Vigorous plants can tolerate some damage from this disease.
Armillaria root rotDogwoodDiseaseArmillaria root rot is a fungal disease transmitted between plants by root contact. Armillaria is often found in newly cleared soils or ones which have been flooded. Symptoms typically include production of smaller-than-normal leaves, leaf yellowing, leaf drop, and dieback of branches. Symptoms may appear on part or all of the plant. White thread-like masses of the fungus may be found beneath the bark near the crown of infected trees, and/or as shoestring-like rhizomorphs, which are dark strands of the fungus growing on or just beneath the soil surface. Honey-colored mushrooms often grow near the base of infected trees in the fall. Infected trees may also exhibit a dark black line in the infected area encircling the base of the plant.
Collar rotDogwoodDiseaseCollar rot is caused by a soilborne fungus which usually infects the plant through wounds on the trunk. It can also infect roots. A canker develops on the trunk near the soil surface or on the roots just below ground. This later becomes sunken and the bark falls off. The tree dies if the trunk is girdled. The first symptom of infection is general poor health, followed by death of twigs and branches. The same fungus causes root or collar rots in several different plant species.
Leaf scorch and leaf rollDogwoodDiseaseLeaf scorch and leaf roll are results of stress. Leaf scorch is characterized by browning of the tips and margins of the leaves. Leaf roll is a puckering and upward rolling of the leaf along the midvein. The undersides of rolled leaves are often pinkish or purplish. Drought, heat stress, overwatering, and construction damage are possible causes of both problems. Leaf scorch can also be caused by over-fertilization. Similar symptoms can be caused by herbicide damage.
Powdery mildewDogwoodDiseaseDogwood powdery mildew is caused by a fungus. It infects leaves, current-year twigs, blossoms, fruit, and buds. The first symptom is often yellow patchy areas on a leaf that become necrotic. White, thin, dry fungal growth may be seen on the lower leaf surface directly below the leaf spots. All plant parts can become covered with mycelia and spores. Infected new growth that is expanding may be distorted. Small, black, pepperlike fungal structures may be seen in the white fungal growth on leaves during late summer and early fall. The fungus overwinters on the leaves.
Brown soft scaleDogwoodInsectBrown soft scales are yellowish to dark brown (adults are usually darker). They are found mainly on twigs, although young scales may also be found on foliage. They overwinter as immatures on host.
Lecanium scaleDogwoodInsectLecanium scales are rounded brown (or mottled) insects. Adults are from 1/8" to 1/4" in diameter. Lecanium scales produce large amounts of sticky honeydew, which may have sooty mold growing on it. They overwinter on the bark, but the crawlers feed on the underside of leaves from May to August (approximately). Scales may be spread from infested plants by people, other insects, wind, and birds.
Oystershell scaleDogwoodInsectOystershell scale insects are usually found on trunks, branches, and twigs. They occur less frequently on the leaves and other plant parts. The mature scale is approximately 1/8" long, brownish or gray in color, and usually elongated like an oyster or mussel shell. Infested plants may show off-color foliage. Scales are spread from plant to plant by birds, people, wind, or insects.