Content
Hydrangea diseases are relatively rare. The plant has sufficient immunity to resist various external weakening factors under normal conditions and subject to the rules of care. However, violations of the terms and conditions of maintenance can from time to time cause diseases of the hydrangea large-leaved. Most of them are reversible and relatively easy to cure.
What are hydrangeas sick
Hydrangea diseases are divided into three groups:
- metabolic disorders
- fungal;
- viral.
There are several dozen types of hydrangea, differing in the shape of the trunk (or bush), plant size, foliage, etc., but diseases, their pathogens and carriers will be common to all species.
It can be argued that the diseases of the hydrangea tree, as well as paniculate, will almost completely repeat each other, both in symptomatology and along the course. Various types of diseases for garden and indoor plant varieties will be considered below.
Diseases of garden hydrangea
Garden species are exposed to harsher environmental conditions than indoor species. In addition, the diagnosis of diseases in these plants can be complicated by a large number of analyzed parameters (after all, it is easier to observe a plant in a pot than in an open field).
Chlorosis
Externally manifests itself in the form of yellowing and drying of the foliage. Usually, the disease initially captures the entire lower leaves, and after 1-2 days the entire hydrangea bush begins to turn yellow.
With chlorosis, the veins may remain green.
The yellowing of the hydrangea is due to a deficiency of iron in the plant. The cause of the disease is either its lack in the soil, or its excessively high alkalinity. It prevents the hydrangea from absorbing this trace element normally.
Treatment of the disease: adding iron salts to the soil, acidifying the soil, changing the plant care regimen.
White rot
One of the most common fungal diseases of hydrangea. The fungus rapidly infects the leaves, stems and roots of the flower. Consuming important substances, it completely deprives the plant of nutrition, from which it can die. Predominantly infects hydrangea in greenhouses. Garden or indoor crops suffer from it less often.
Symptoms: a white bloom like cotton wool and darkening hydrangea shoots, rotting near the ground.
The fungus spreads very quickly and is able to completely cover the surface of the leaves.
Complex treatment is necessary: the affected areas should be removed and burned, treating the sections with a solution of potassium permanganate. Partially damaged and adjacent healthy bushes should be sprayed with copper-containing preparations.
Powdery mildew
It mainly affects young hydrangeas with a lack of root nutrition. In some cases, the disease provokes excessive nitrogen fertilization of the bush.Symptoms: Numerous faded yellow-green spots.
At a later stage, the disease is characterized by purple spots on the leaves.
This type of fungus affects only hydrangea (each culture has its own powdery mildew pathogen), so it is safe for neighbors of other species.
Treatment of the disease consists in the destruction of damaged areas and treatment of the foliage with Fitosporin or Topaz.
Septoria
Fungal disease that manifests itself at low temperatures and high humidity. Symptoms: spots up to 0.5 cm in diameter, light in the center and dark at the edges.
After the appearance of white spots in the center, they are covered with small holes, from which the spores of the fungus are sown
Treatment: removal of damaged areas, treatment of the cut with potassium permanganate, spraying with copper-containing preparations and special agents, for example, Rodomit Gold.
Ring spot
It is mainly a disease of hydrangea paniculata. A viral disease that does not depend on weather or care to spread. Symptoms: ring-shaped spots appear on the hydrangea.
In the later stages, the spots darken and the leaves shrivel
There is no cure for the disease, since there are no effective drugs. The hydrangea is likely to die, so to avoid spreading the infection, the bush should be destroyed.
Hydrangea cancer
Oncology is characteristic not only of animal organisms, but also of plants. Symptoms of the disease: numerous brown spots, ulcers appear on the back of the leaf under the spots.
With the development of the disease, the spots merge into larger ones, and the leaves dry out
The causes of hydrangea cancer are unambiguously unknown; it is believed that it is provoked by mechanical damage to the bush. Treatment consists of removing the affected areas. The disease is currently considered non-contagious.
Lack of flowering
Hydrangea may not bloom for several reasons:
- erroneous pruning of last year's shoots, on which buds are formed;
- freezing of buds;
- too much direct sunlight;
- irregular watering and feeding.
The solution to the problem is aimed at overcoming the indicated factors: the use of scattered light, the shelter of the plant for the winter, etc.
Diseases of room hydrangea
In general, room hydrangea leaf diseases are repeated garden ones. The only difference is that plants in the open field are more susceptible to fungal diseases, since the humidity in the garden will always be higher than at home.
Peronosporosis
Like all fungi, this disease occurs in high humidity, but requires elevated temperatures for normal development. Symptoms are oily spots on stems and leaves, which eventually turn grayish-brown in color.
Leaves affected by peronosporosis lose their shape and curl
Treatment of the disease consists in removing damaged areas (up to the entire stems) and spraying the plant with a 1% solution of Bordeaux liquid or drugs similar in action (Kuproskat, Optimo, Kumir, etc.)
Gray rot
Mostly this fungus attacks young leaves, in rare cases - shoots. The reason is excessive waterlogging of the room, too frequent and abundant watering, room shade, overcrowding of plants.
At high humidity, gray rot quickly spreads throughout the plant
Treatment of the disease consists in the timely removal and destruction of the affected areas. Then the flower should be sprayed with a solution of potassium permanganate. If the lesion has become global, the best option would be to completely destroy the plant so that the disease does not spread to neighboring ones. It is also recommended that bushes with a lesion level of less than 30% are sprayed with Fundazol.
Dry blackening of foliage
In some cases, when the hydrangea is sick, it will develop brown spots on the leaves. Gradually, they cover the surface of the entire plant.
The middle stage of the disease partially affects all leaves
The reason is watering the hydrangea with hard water and sunburn. The treatment of the disease in this case is very simple - use settled water and place the flower in the shade.
Wet blackening of foliage
In the event of a sharp change in temperature or an increase in humidity, droplets of water appear on the leaves, after which they begin to turn black.
The plant loses its shape, its branches droop
Coping with the disease can be very simple - by placing the flower in conditions (temperature and humidity) that are appropriate for growing. At the same time, it is recommended to reduce the dose of watering for the next month by half.
Phyllostic spotting
The manifestation of the disease is observed in the form of merging dark red spots with a lightening center. Subsequently, the spots expand, and a crimson border stands out along their edges. Then there is the appearance of spores in the form of small black dots.
Phyllostic spotting in the late stage of the disease irrevocably destroys the leaves
Treatment is standard for fungal diseases - removal of damaged areas and prophylactic treatment of foliage with copper sulfate 1%.
Ascochitous spot
The symptomatology consists in the appearance of rounded spots, which, growing, acquire an irregular shape. Sometimes the spots are surrounded by a dark brown or crimson border. In the dead tissue in their centers, the fruiting bodies of mushrooms are formed, which overwinter in this form.
Ascochitous spot mainly affects the leaves in the upper part of the plant.
Treatment consists in removing the affected areas with their obligatory destruction. This is followed by preventive treatment with copper-containing preparations.
Rust
Fungal infection that occurs with excess water and nitrogen fertilizers. Symptoms: Small yellow or brownish-brown specks that later develop into brown growths. Rusty spores spill out of the growths.
Most often, rust is localized at the edges of the foliage.
Treatment consists in removing damaged leaves and treating the plant with copper chloride at a concentration of 40 g per 10 liters of water. You can use the drug Topaz.
Hydrangea pests and control
Most often, the plant is attacked by various types of insects. But the list of pests is not limited to arthropods alone. A weakened hydrangea can suffer from protozoa and slugs. The most common pests are listed below.
Aphid
It is a small parasitic insect that feeds on plant sap. Aphid colonies are always clearly visible on the leaves. Often a sign of its presence is ants eating the honeydew secreted by it (droplets of sweet liquid).
In large numbers, aphids can pose a serious threat to any crop
Treatment consists in treating the plant with insecticides: Fitoverm, Streda, Iskra. In the case of small colonies, you can do with folk remedies - soapy water or simply rinsing insects from the leaves with water from a hose under pressure.
There is also a biological way of fighting with the help of ladybirds, natural enemies of aphids. To attract them, you can plant marigolds near the hydrangea.
Spider mite
Small arthropods that also feed on plant sap. They appear mainly in the hot season or during drought. Symptoms: the presence of cobwebs on the leaves. With a large number of colonies, they are visible with the naked eye from the underside of the leaves.
Leaves affected by spider mites may curl
Treatment is the same as for aphids. If the colony is small, soapy water is sufficient. If it grows to a large size, chemical action is necessary.Conventional insecticides may not be enough, so special anti-tick agents are used - acaricides. These can be: Akrin, Akrophyte, Apollo, Vermitic.
Molluscs
Garden snails and slugs can be dangerous to hydrangeas, especially young plants. In adults, they eat fresh leaves, growth zones and newly opened buds. Mollusks acquire maximum activity during periods of high humidity.
The presence of slugs can be detected by characteristic damage to the leaves.
Another sign of their activity is footprints on the paths and stems of plants.
Mostly molluscs are harvested by hand, destroying their resting places and egg laying. Beer traps can be an effective remedy.
Sometimes they are used to exterminate slugs from their natural enemies - birds or toads. Treating hydrangeas from these pests using chemicals (for example, Molluscicide) has certain risks, since all such products are toxic.
Nematode
This pest is the simplest one that affects the roots of the plant. From there, the worm enters the trunks. The danger is represented by its waste products, which are poison for plants. External manifestations of the nematode are red galls on the leaves and characteristic root lesions.
Tuberous lesions of the root system are characteristic of nematodes
The fight against the pest is preventive in nature. For this, sugar is added to the soil, which is food for other types of microscopic worms that parasitize on nematodes. Preparations Aktofit and Fitoverm should be applied a few days before planting plants in the ground.
May beetles
The larvae of these insects feed on plant roots. Hydrangea may also be among the victims of these pests. Damage to the root system leads to a deterioration in plant nutrition, it can wither or even completely die.
If clutches of beetle beetle are found, they should be immediately destroyed.
Preventive treatment for larvae consists in watering the hydrangea with infusion or decoction of onion peel. Spraying the bushes with a solution of ammonia (20 ml per 10 liters of water) will also be effective.
Medvedka
The omnivorous nature of the bear is well known. This insect, in the absence of natural food sources, can damage the roots of ornamental plants, including hydrangeas.
A sign of the appearance of a bear will be numerous burrows of small diameter in the area
The fight against the bear is complex. The use of traps, poisonous baits, as well as the preventive treatment of hydrangeas with insecticides should be combined.
Night scoops
The larvae of these butterflies are capable of causing irreparable damage to the plant in a relatively short time, since the speed of eating leaves by them is very high. Sometimes the devastating effect of caterpillars can destroy an entire bush in less than one day. Therefore, it is necessary to regularly inspect hydrangea leaves to detect this pest.
The scoop caterpillars eat out large holes in the leaves
To combat scoops, contact insecticides are used, which are sprayed on the leaves monthly, starting in May. Birds attracted to the site will be an effective way of controlling the pest.
Prevention of diseases and pests
Practice shows that preventive measures carried out at the required frequency require much less effort than treating a plant in case of infection.
The main measures for the prevention of hydrangea include:
- maintaining the correct acidity and mineral composition of the soil;
- observance of the cut-off regime: hydrangeas need diffused light and partial shade;
- careful selection of seedlings for planting;
- regular soil mulching;
- disinfection of garden tools after each and destruction of all cut shoots or leaves;
- treatment of hydrangeas in early spring with antifungal drugs.
Spring treatment of hydrangea consists of antifungal copper-containing preparations, for example, a solution of copper sulfate 1%. In the summer, usually no preventive action is taken, but in the fall you can treat hydrangea from diseases and pests with a solution of 3% Bordeaux liquid.
Conclusion
Diseases of hydrangea, with proper plant care and appropriate weather, almost never appear. Both bush and standard forms have strong immunity and, with the correct approach to agricultural technology, successfully fight against any pathogens. In those rare cases when the disease still attacks the hydrangea, its treatment does not present any particular problems and is reduced, mainly, to adjusting the conditions of keeping the plant and treating it with appropriate drugs.
