There is no practical chemical treatment for either disease, although fungicides may prevent the disease from spreading to other plants. Most are evergreen but some are deciduous. The most common diseases reported on azaleas include petal blight, leaf and flower gall, and various azalea declines. Size 1.2m+ after 10-20 years. If planted in shade, they will become open branched, flower less profusely, and be prone to powdery mildew and fungus. The Azalea Chapter of the American Rhododendron Society offers information and resources on rhododendrons for members and the public. Dieback, a fungal disease triggered by stress, causes foliage to … Azalea pests and diseases. If azalea foliage or flowers are being spoiled by lace bug or petal blight, preventative action – taken at the right time of year – can ease the problem. Borers and stem borers can attach deciduous azaleas, making small homes in the branches and laying their eggs in it. However, they are subject to a number of problems caused by infectious agents, insect pests, weather and nutrition deficiencies. Azaleas are beautiful flowers that are easy to plant and maintain, and they bloom in many different colors. Root rot is a serious, but common disease that is caused by excessive moisture in the soil. Click here for deciduous azalea webshop. Rhododendron usually refers to evergreen plants with large, leathery leaves. Affected leaves eventually turn brown and should be removed and destroyed. Young plants grown in heavy shade are the most seriously affected by this disease. Deciduous Azaleas prefer full sun but will tolerate light shade. And . Azalea arborescens, Azalea viscosum, and Azalea vaseyi, however, will tolerate more shade than others. Hardiness very tough: mostly H5-6. Foliage – Azalea foliage tends to be elliptical shaped, thin, small and pliable. A fungus named phytophithora is a common disease problem for rhododendrons and azaleas. Asexual conidia are most frequent; they spread by wind and produce new colonies that produce more spores. The name Azalea is used to refer to evergreen Oriental species and hybrids, as well as deciduous native plants. It is only sporadically severe. They originate mostly from the Northern Hemisphere with high concentrations in western China, the … It is a watery mold that thrives in wet conditions. Please note: This content may be out of date and is currently under review. They are tough and fast growing plants typically reaching 125-150cm (4'-5') in 10 years. Disease pests include blights, canker, crown rot, leaf gall, root rot, leaf spot, rust and powdery mildew. Hand picking infected leaves is the recommended method of control. Types Certain hybrids and azalea cultivars are more susceptible to rust than others. Plants that exhibit stunting, chlorosis, and die-back symptoms should first be examined for problems with planting depth, soil pH or drainage. Azalea plants are members of the Rhododendron species, and sometimes the names are used interchangeably. Petal blight is most severe during cool, wet spring weather. Problem only in azaleas; rhododendrons are resistant ; Leaves on one to several branches turn red to yellow, wilt, die and fall off; Dark olive to gray streaks are often visible in the sapwood if the bark is peeled back; The entire canopy may show symptoms in a single season or take several years Wonderful flowers but sick looking foliage is not the best look, so what causes Azalea foliage to look so untidy? Rhododendron foliage is large, paddle shaped, thick, and evergreen. One of the most common problems with azaleas is the ‘black spots’ that appear on the foliage. . They are very small and barely visible to the naked eye. Exbury Deciduous Azaleas are obviously not an evergreen, they do lose their leaves during the winter, but they are striking when in bloom! Infection first appears as small, white spots on colored petals or rust-colored spots on white-flowered varieties. Leaf rust is a common azalea fungal disease that, though rarely serious, causes unattractive foliage spots. Plants that are set too deep are frequently affected by the diseas… Many pests can damage azaleas. Azalea and Rhododendron Diseases – Penn State Extension The most common azalea diseases affecting these shrubs include: Azalea Gall This azalea disease commonly occurs in early spring on new leaf growth. Insect pests include aphids, borers, lacebugs, caterpillars, leafhoppers, mealybugs, nematodes, scale, thrips and whitefly. It is a dense, bushy, suckering shrub that typically grows 2-6’ (less frequently to 10’) tall. Azalea Dieback Diseases Two fungal diseases can cause azalea branch dieback: Botryosphaeria and Phytophthora. From then on, all you have to do is worry about the many bugs and diseases that can attack your azaleas and rhododendrons, such as lace bugs, … Pest infestations in azaleas rarely occur, but … Rhododendron periclymenoides, commonly called pinxterbloom azalea, is a deciduous shrub that is native to moist woods, swamp margins and open areas from Massachusetts to South Carolina and Tennessee. Read on to learn about the causes, effects and treatments of a few diseases that affect azaleas. Mites, such as azalea mite (Eotetranychus clitus) and southern red mite (Oligonychus ilicis), are a common problem on azaleas and may also attack rhododendrons. The flower color range includes yellows, oranges and fiery reds. Symptoms include leaf curling and droop. Lacebugs are a common insect that dine on leaf chlorophyll, leaving behind yellow speckles. Insects, Diseases, and Other Plant Problems: Rhododendrons are susceptible to insect and disease problems. 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