Azalea: Lime-induced chlorosis categories: Azalea Azalea Diseases Ornamentals Shrubs revision date: 2022-11-30 12:00 Lime-induced chlorosis on rhododendronPhoto by: R.S. Byther Biology Lime-induced chlorosis, or leaf yellowing, is caused by alkaline soil conditions. High alkalinity of soils can make iron or manganese unavailable to plants, causing leaf chlorosis. Pale to bright yellow leaves, particularly on the […]
Azalea: Marginal leaf necrosis categories: Azalea Azalea Diseases Ornamentals Shrubs revision date: 2022-11-30 12:00 Rhododendron marginal leaf necrosisPhoto by: R.S. Byther Biology Leaf burn on azalea is a response to stress. Leaves turn brown, especially at the tips and along the edges. Water stress (too much or too little), root or stem damage, excess fertilization, […]
Azalea: Nematode (stunt) categories: Azalea Azalea Diseases Ornamentals Shrubs revision date: 2022-11-30 12:00 Biology Nematode problems are most common in nursery plantings. Nematodes are tiny, worm-like parasites found only in the soil that feed on the roots. The root damage causes an overall stunting of affected plants, and plants may also show signs of drought […]
Azalea: Ovulinia petal blight categories: Azalea Azalea Diseases Ornamentals Shrubs revision date: 2022-11-30 12:00 Azalea Ovulinia petal blightPhoto by: R.C. Linderman Biology Ovulinia petal blight affects the flowers only (not leaves or shoots) of azaleas and rhododendrons. Infected flowers first display small, water-soaked spots which enlarge quickly. The petals quickly become slimy and turn brown, […]
Azalea: Powdery mildew categories: Azalea Azalea Diseases Ornamentals Shrubs revision date: 2022-11-30 12:00 Azalea powdery mildewPhoto by: R.S. Byther Biology Powdery mildew on azalea forms a characteristic fuzzy white growth on upper or lower leaf surfaces. Entire leaves can be covered. In late summer and fall, small black specks may be found in the white […]
Azalea: Root rot (Phytophthora) categories: Azalea Azalea Diseases Ornamentals Shrubs revision date: 2022-11-30 12:00 Phytophthora root rot damage to trunkPhoto by: R.S. Byther Biology The symptoms produced by Phytophthora root rot are often confused with those caused by environmental or cultural problems. Above ground, infected plants may show stunting, yellowish-green leaves, branch dieback, wilt, and […]