Rust on azalea. No … Common Diseases. Repeat application every 10 days until control is obtained. Should I treat the others before they go too? Like any plant in the garden, azaleas are susceptible to a range of specific diseases which may mar the beauty of the plant. Indian and kurume azaleas are especially susceptible. Rust is caused by a group of fungi from the Pucciniales order. Leaf galls, rust, petal blight and leaf spot are caused by fungus and should be treated with fungicide. I do not find any bugs. Symptoms Shamrock plants that develop powdery mildew exhibit symptoms such as white patches of powdery fungus on stems, leaves, flowers and buds. Rhododendrons bloom in late spring and provide a burst of color before summer flowers set in. The rust of cultivated rhododendrons is C. reticulata, a native North American rust that spread to nurseries from Ledum. RUST is usually noticed when a cloud of orange powder shoots out from a lawnmower. They … Azalea Diseases. Bleach can be helpful for disinfecting pruning tools. Rhododendrons are quite easy to grow as long as you have well drained but moist acidic soil. Petal blight appears as tiny white spots on flowers. Also do not plant rhododendrons near Hemlock trees. It has been observed that the inner parts of the bark of the dying branches develop a reddish brown discoloration. Leaf rust is a common azalea fungal disease that, though. Wet surfaces are also needed to cause infections. Healthy azaleas add vibrant color to any landscape. Here is a summary of pests, disesases and problems you may find while growing rhododendrons and recommended solutions from various sources. Rust diseases are unsightly and often (but not always) reduce plant vigour. My George Tabor azaleas have tiny rusty spots on old growth and new growth. It is likely to be more severe in shady areas. Rust is spread by spores that are transferred from infected plants to healthy plants. If rust appears good circulation may help. The leaves will also have orange gelatinous spots and can become distorted or stunted. Brown spots on Azalea leaves are common yet treatable. By: Susan Patterson, Master Gardener Printer Friendly Version. When Rhododendron occurs, there will be small brown … These spores can be transferred either by the wind or by water, which is why rust disease often spreads after watering. The disease is most often in plantings along the coast. I just became aware of this in last couple of months (it may have been existence long before), and seems to be spreading. Azalea Rust. Two diseases… Deciduous azaleas are the primary group of broadleaved shrubs damaged by rust. Leaves off-color with white, powdery coating: Powdery mildew: 2. Rust diseases occur most often in mild, moist conditions. This is a fungal disease and occurs because of excess humid conditions. Symptoms are easily recognized by the brightly colored yellow-brown spores present in disease pustules on the lower or upper surfaces of leaves. I have a dozen large, mature, beautiful azaleas in my yard. This is second year, first year also had spots. Root rot/Water mold . Brown areas turning white with small black dots: Pestalotia leaf spot: B. Black spores are visible on leaves and stems in fall and overwinter inside infected stems which are distinguished by dark, corky blotches at points of infection. Some plants are 8 ft high. How To Guides; Myrtle Rust; Community. Leaves with definite brown areas: 1. I have scores of azaleas (different colors) - perhaps 60+ years old - and have noticed many, many of them have some kind of fungus on them which appears to be killing the branches, and sometimes the entire plant. Disease or Pathogen: I. Rust diseases. This fungal disease, caused by Ovulinia azaleae, primarily affects the flowers of azalea, but mountain laurel and rhododendron flowers can also be infected. Caused by the fungus Microsphaera penicillata, this disease causes azalea and rhododendron leaves to discolour and become coated with a white powdery fungal growth.Control of the disease is difficult, especially in certain weather conditions that favour the disease, i.e. Diseases Powdery mildew. As a whole, these organisms attack plants of every description, but each rust subtype can typically attack only a very narrow range of plants. … Localized brown or red-brown spots: Leaf spots : 2. They wont tolerate deep and dry shade and poor drainage/heavy clay soil. The main diseases of Rhododendron are root rot, brown spot and iron deficiency chlorosis. When rhododendrons and azaleas are properly planted and maintained, insects and diseases are less of a problem. There are a number of different Rhododendron diseases, with the most serious being root rot and dieback of the branches. The disease depends on the cool, moist conditions of late fall. Rust Disease On Plants. Rhododendron usually refers to evergreen plants with large, leathery leaves. The following is a brief introduction to the disease control methods of Rhododendron. This article is a list of diseases of azalea (Rhododendron spp.). The leaves have turned brown or rust colored. Here is a quick guide to pests and diseases that Rhododendrons can be prone to. Identify symptoms of the disease on the azalea to make sure the infection is present. Browning of leaves at edges and near tips: Winter injury: 3. This rust is only sporadically severe and typically infects deciduous azaleas. 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. Rhododendron are evergreen, flowering from late autumn to early summer. Rust Rust appears as orange-red spots on the lower surface of the leaf. EXPERT ADVICE. Is this treatment something a registered hortaculturist should do? Page last updated: Monday, 9 June 2014 - 9:36am. Rhododendron bushes are similar to azaleas and members of the genus Rhododendron. An azalea plant with wilted, drooping foliage may be suffering from root rot (also known as the fungus Phytophthora). Avoid rhododendron varieties susceptible to rust. Their size varies but is typically less than a ½ inch in diameter. Azalea pests and diseases. Rhododendron grows weak, leaves wilt, dry and die directly when it is seriously ill. How can a flower lover bear to see such a situation? Excess watering and stagnant water causes root rot disease and causes your azalea to drop diseases. Azaleas Good Azalea Care: Azaleas, Noteworthy Shrubs For Any Garden Azaleas Azalea Problems: Azalea Diseases & Pests This condition is caused by a fungus called Botryosphaeria dothidea. Image by NinaMalyna. I'm heartbroken. when planted. Look for tiny, round, yellow spots on the upper surfaces of leaves, and orange coloured pustules on the undersides. Avoid treating the azalea for rust without making sure it is infected. Other diseases of Rhododendron include petal blight, leaf gall, and leaf spots. Rust disease is caused by a fungal parasite that needs living plants to survive. Rhododendron Pests and Diseases. Typically fungal in nature, these diseases steal the vibrance of your Azaleas. Azalea petal blight.jpg . Rust fungus grows within the leaf so there is usually a copy of the spores on the underside of the leaf as well.