Rhododendron diseases – veiled dangers
Twisted, dry leaves or spotting of various types can spoil any ornamental plant. Diseases of rhododendrons are so dangerous that they attack neighboring flower crops with lightning speed. A detailed acquaintance with some of them will help the gardener to take the necessary measures in a timely manner. Knowing the causes of fungal infections, it will be easier for the farmer to prevent the occurrence of dangerous ailments.
Common diseases of rhododendrons
Improper agricultural techniques for growing flowers leads to the development of pathogenic microorganisms. In alkaline soil, the plant is quickly depleted, and in wet (clay, sand) it begins to get wet, wither and rot. Moreover, in open sunny areas, the foliage of the culture is covered with burns. Incorrect composition and dosage of fertilizers, as well as sudden changes in temperature, provoke the appearance of debilitating diseases and pests of rhododendrons. Treatment and feeding in such cases should be strictly regulated. In addition, it is necessary to regularly carry out preventive measures in order to increase the plant’s resistance to infections..
Tracheomycotic wilting or when leaves curl
Fungal microorganisms infect the root system of the bush, and the underground part begins to rot at an accelerated rate. In this state, it is not able to deliver nutrients to the culture..
The first signs of this rhododendron disease are:
- white bloom on the stems;
- brown spots;
- fast drying of green mass;
- leaf fall (together with petioles);
- wilting shoots.
The rhizome is covered with a gray-white mycelium. The process of dying off of living tissues occurs quickly enough. The main reason why the leaves of rhododendrons curl is the blockage of blood vessels by fungal spores..
The infected parts of the bush are removed and disposed of. The remaining stems are treated with a Bordeaux mixture. Prevention – watering and spraying the plant with Fundazole solution (0.2%).
Yellow leaf mosaic
Alpine flower varieties are especially affected by this virus. Dangerous infection is carried by insects such as aphids or bedbugs.
A photo of this rhododendron disease clearly demonstrates its manifestation:
- yellow-green tint of foliage;
- swollen, dark-colored calluses;
- thin leaf plate.
In a short period of time, the bush turns into a terrible sight. If not disposed of, the disease will quickly spread to neighboring crops..
What if the leaves of rhododendrons turn yellow? It is worth knowing that such a bush cannot be treated. It is uprooted and burned. The flowerbed is treated with Confidor or another strong insecticide.
Spotting is not Variegata
Sometimes the plant sheds its foliage prematurely. However, before that, it begins to turn yellow and becomes covered with brown spots of irregular shape. Massive colonies of spores in the form of gray pads form in the dead areas.
There are several types of spotting:
Damaged parts of the flower must be cut off. The remaining greens are sprayed with a solution of copper sulfate, Camulos or Bordeaux liquid.
Most of the leaves are dry brown spots with a red border. As the virus progresses, black sporangia appear on the surface. Having familiarized yourself with the photo of rhododendron diseases and their treatment, it will be much easier to cope with a dangerous enemy.
In order not to harm the culture, all therapeutic measures are carried out at low air humidity. Otherwise, terrible burns will appear on the bush..
Rot in all its forms
The cause of the onset and development of fungal diseases of rhododendrons is the high moisture content of the soil..
As a result, brown spots or necrosis appear on:
- young shoots;
- flower petals.
With advanced forms of fungal infections, a fluffy coating of a smoky shade forms on the deciduous plates. Sometimes it takes on a filamentous structure, which resembles a web of a spider’s web..
The parts of the culture damaged by the fungus are completely destroyed. Then they carefully observe the condition of the bush..
The best way to combat rot is through prevention. For this, the plantings are sprayed and watered with a 0.2% Fundazol solution or other copper-containing preparations. Events are held every 2 weeks.
Wax disease is a collective responsibility
In some cases, the occurrence of infectious diseases can be triggered by several types of fungal spores at once..
The main symptoms of rhododendron wax disease are:
- deformation of foliage;
- thickening of deciduous plates;
- the appearance of yellowness;
- reddish brown spotting;
- the formation of white growths.
At the first signs of damage, the evergreen shrub is cut off. Then the crown is sprayed with a solution of the drug Cumulus. Gardeners recommend carrying out the procedure in the spring to improve the effect..
While these are just some of the rhododendron diseases and their treatments, it is also worth mentioning:
- late blight;
- bacterial cancer;
If the tips of the leaves begin to turn yellow, it means that the plant suffers from high acidity of the soil. The bush is sprayed with two types of sulfate: magnesium and iron. The drug is diluted in a ratio of 7 g / l.
According to many growers, rhododendron diseases are the result of improper care of the shrub. All he needs is planting in the right place and monitoring the condition of the plant.