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Problem
(factsheet)
Plant NameTypeDescription 
Cold injuryCamelliaDiseaseCamellia leaves are sensitive to direct sunlight, which kills leaf tissue. Sunburn occurs when the shrub is planted in full sun or against a south- or west-facing wall. Winter sunlight can induce sunburn when low soil temperatures induce slower metabolism in root systems. Excessive daytime transpiration rates coupled with reduced soil water uptake creates moisture stress in leaves. This causes brown areas to spread along leaf margins, weakening the plant. Damage is most severe on the side of the plant exposed to sun and/or air flow. Buds and stems may also die as a result of unusually cold conditions. Drooping and rolling leaves may occur as a protective reaction to reduce the surface area exposed to the cold. These leaves usually return to normal in spring.
Flower and petal blightCamelliaDiseaseFlower and petal blight is a fungal disease of camellia flowers. Leaves, stems, and roots are not attacked. Symptoms begin with development of brown spots on the petals. These spots quickly enlarge until the entire flower is brown and dry or leathery and drops from the plant. Dark brown veins in lighter brown petals are a characteristic symptom. Olive-brown or black fungus bodies, up to an inch in diameter, can develop in the bases of infected flowers. These fungal structures persist in the soil, causing reinfection. This disease may be confused with injury caused by weather, which is usually only found on the outer margin of flowers. Disease development is favored by cool, wet conditions. All species and varieties of camellia appear equally susceptible to this blight.
Leaf gallCamelliaDiseaseLeaf gall is caused by a fungus, and results in the formation of off-colored, thick, fleshy leaves in early spring, shortly after bud break. Through April and May, the galls are obvious and range from greenish pink to rose in color. During the growing season, the galls shrivel and turn black, and eventually fall off. Although the symptoms appear dramatic, the damage is usually economically insignificant. In the nursery, however, it can cause tremendous damage if left unchecked. Young plants with few shoots can become severely malformed.
OedemaCamelliaDiseaseOedema, or edema, is a condition which may result from excess water in the soil or high humidity. Usually found on the lower leaf surface, oedemas initially resemble protruding watery blisters or galls. Later the blisters may become brown or yellowish in color and appear corky or roughened. Some chlorosis (leaf yellowing) may also be associated with oedema as a result of decreased nutrient uptake.
Ramorum leaf and shoot blight (Sudden oak death)CamelliaDiseaseRamorum leaf blight is caused by Phytophthora ramorum, the same organism that causes sudden oak death (SOD). In Washington, most cases have been found in nurseries on rhododendrons and camellias, which are highly susceptible to this disease. Some oak species, viburnum, kalmia, and Pieris are also considered highly susceptible, along with native plants such as salal and evergreen huckleberry. On camellia, damage consists of brown, irregular, water-soaked lesions with diffuse margins. These lesions typically begin at the leaf tip and spread up the midrib. Occasionally, lesions form at the edge of the leaf, as well. Lower leaves usually drop before the damage reaches the stem. Canker and shoot dieback symptoms have not been seen on camellias. Symptoms of this disease may strongly resemble those caused by sunscald, chemical damage, or cold injury, but these common problems typically have clearly defined margins. Also, P. ramorum has a wide and varied host range, so camellia is seldom the only species affected. IT IS NOT POSSIBLE TO CONCLUSIVELY DIAGNOSE THIS PROBLEM BASED ON VISIBLE SYMPTOMS ONLY. In Washington, Ramorum leaf blight has so far been found only in association with infected nursery plants and water runoff from infected nursery sites. While this disease has the potential to become a serious and economically significant problem, it is not yet considered to be widespread in Washington in either cultivated or native landscapes. P. ramorum infection is NOT LIKELY in the landscape UNLESS the plant (1) is a highly susceptible species AND (2) was purchased since 2002 AND (3) is showing symptoms associated with P. ramorum infection (or is located near another plant that meets all these criteria). Currently, the only way to confirm a SOD diagnosis is with laboratory tests.
Sooty mold (Black mold)CamelliaDiseaseSooty mold is a fungal growth often found on plants infested with honeydew-producing insects, such as aphids and scales. The fungus does not attack the plant but simply grows on the honeydew. Sooty mold typically causes little damage to plants, though it may become an aesthetic problem. Very heavy mold coverings on leaves can interfere with photosynthesis and cause some plant decline.
SunburnCamelliaDiseaseCamellia leaves are sensitive to direct sunlight, which kills leaf tissue. Sunburn occurs when the shrub is planted in full sun or against a south- or west-facing wall. It only takes one hot summer day for damage to develop. In excessive heat and sunlight, transpiration rates exceed water uptake from the soil, causing leaves to experience moisture stress. Leaves develop irregular brown areas along the edges which eventually spread inward along the ribs. Another type of sunburn occurs with new growth in spring during cloudy weather. Before the leaf tissue can harden or mature, a bright sunny day occurs. Tissue damage appears in the center of the leaf (not the edges). Damaged leaves are seen mostly on south and southwest exposures. Although undesirable aesthetically, sunburn does not significantly damage the plant. Weakened leaves are, however, in greater danger of fungal or bacterial infection.
VirusCamelliaDiseaseThe camellia yellow mottle leaf virus is transmitted by propagating from an infected plant or by grafting from an infected plant to a healthy one. Sometimes the virus is purposefully transmitted to foster variegated leaves and flowers. Irregular yellow splotches appear on leaves, while unaffected portions remain dark green. Colored flowers might display white blotches. The disease is mostly harmless unless there is extensive leaf yellowing, which results from the suppression of chlorophyll development. Leaves produce less food, and the plant becomes weakened.
AphidsCamelliaInsectCamellias are infested by black citrus aphids and other aphids. The black citrus aphid is a small reddish-brown to black insect typically found on new growth and flower buds. These aphids may be found at any time of year, particularly on plants in protected sites. Other aphid species may be brownish or green, and are also often found on new growth. Aphid feeding typically causes distortion, twisting, or cupping of developing leaves. Aphids often produce large amounts of honeydew, a sweet, sticky material which may become covered with a dark growth of sooty mold.
Brown soft scaleCamelliaInsectBrown soft scales are yellowish to dark brown insects (adults are usually darker). They are found mainly on twigs, although young scales may also be found on the foliage, typically on the underside of leaves. Soft scales produce large amounts of honeydew, a sweet, sticky material which may become covered with a growth of dark sooty mold. Heavy scale infestations can cause plants to become yellowish and wilted in appearance.
Cottony camellia scaleCamelliaInsectThe cottony camellia scale is a flat brownish or yellowish insect. The scales overwinter on twigs or evergreen leaves. In the spring, adult females lay cottony egg masses on the underside of leaves. Crawlers (young scales) feed on the underside of leaves. Cottony camellia scales produce large amounts of honeydew, a sweet sticky material which is often covered with a growth of black sooty mold. Foliage with scale infestations may turn yellowish or pale in color. The cottony camellia scale is also found on yew and holly.
Root weevilsCamelliaInsectRoot weevils are small flightless beetles with a snout. The adults are black or mottled and approximately 1/4" long, depending on species. They feed on the leaves by crawling up the stems and chewing semicircular or irregular notches on the leaf margins. Adults begin feeding around June to August, depending on the species, but adult feeding does little damage. Larvae are white, legless grubs about 1/4"-3/8" long and are found in the soil around the roots of affected plants. They feed on the roots and can girdle and destroy roots, causing decline or death of plants.