Powdery mildew on roses: description and control measures

Powdery mildew is an infectious disease caused by fungi. Its traces can be seen not only on flowers, but also on crops, fruit trees and berry bushes.

Spores of this pathogen are characterized by long viability. They can "sleep" in the soil for several decades.

Activation occurs when favorable conditions for reproduction occur.

There are several types of fungi. Powdery mildew on roses is caused by Sphaeroteca pannosa. Its activators are heat, high humidity, an excessive amount of nitrogen compounds in the soil. Most often, rose bushes, which are dense, become infected. Therefore, a musty odor floating around the plant can be considered an indirect sign of the disease.

How to identify powdery mildew and how dangerous it is

First of all, the stalks, petioles and young shoots that are lower than the rest are infected. A white coating forms on them, in which the mycelium can be recognized. After the spores mature, water droplets appear on it. In the absence of timely treatment, sores spread to the entire plant.

As a result, its appearance becomes unattractive, and the aroma emanating from roses changes for the worse. This can be explained by a lack of nutrients.

Leaves captured by powdery mildew, suffer from necrosis, turn yellow due to lack of photosynthesis. Flowers stop blooming, buds are very small.

The plant at the last stage of this ailment is a bare stem, on the surface of which you can see only felt plaque. Due to its structure and features of the latter, the rose does not develop. The resulting cracks become a haven for rot pathogens. Such a bush is unlikely to winter.

The disease has several names. In addition to the generally accepted, there are such popular designations as "linen", "ashtray" and "torment". Obvious symptoms make diagnosis easier.

Pathogens can be transferred from a diseased plant to a healthy one using insects, wind or pests.

The peak activity of fungi begins in June.

The causes of powdery mildew and the general principles of the fight against it on indoor roses

There are a lot of factors that can provoke a disease in plants grown at home:

• contact of healthy roses with patients;
• rains falling too often;
• a sharp change in temperature;
• high humidity;
• excess nitrogen and lack of minerals in the soil and other errors during agricultural activities.

To cure the disease, contact and systemic fungicides will be required. The list of the most effective include Fundazol, Amistar Extra, Topaz, Vitaros, Acrobat MC, Skor, Previkur.

Their action can be supplemented with spray formulations prepared according to folk recipes. Before processing, all damaged shoots, leaves and buds should be removed.

Powdery mildew treatment with folk remedies

The sooner an ailment is noticed, the better. Gentle methods will give a good effect if the fungus does not have time to germinate into the internal tissues. The main stage should be preceded by proper preparation, while the affected peduncles and leaves are removed (they differ in a painful appearance and yellow color).

If the disease has been progressing for a long time, pruning should be cardinal. It is not worth it to feel sorry for the removed parts of the plant.

Colonies of mycelium located in the soil are removed by removing the topsoil (if the rose grows in a pot).

The sprayed solution should cover the entire plant. Experienced gardeners recommend dipping the bushes completely. This is the only way to achieve maximum effect. One treatment is usually not enough, the duration of the course is determined based on the composition of the drug.

It should be noted that alternative methods can stop the disease, but not completely eliminate it. Most often you can’t do without special tools.

Processing should be carried out in dry weather. It is advisable that there is no strong wind and heat. Harvesting the composition for future use is not recommended. You need to do as much as you need at one time.

Powdery mildew treatment with fungicides

If alternative methods did not give the desired result, and the condition of the rosary constantly worsens, you will have to use special drugs. In their functions, the stopping of negative processes and the complete elimination of the pathogen. Additional bonuses include restorative action.

Fungicides can be biological and chemical.

The former are considered safer. Many use them as growth stimulants. Unfortunately, they do not differ in high efficiency in relation to a severely neglected ailment. Means from this category are most often used for prevention.

Fungicides of chemical origin can harm both humans and the environment. They should not be abused. The advantages of these drugs include fast and powerful therapeutic effect.

With prolonged use of the same drug, addiction is developed in pathogenic microorganisms.

Mr. Dachnik recommends: measures to prevent the disease

Powdery mildew is easier to prevent than to cure. To reduce the risk of infection of rose bushes, you must:

• timely remove the affected parts of the plant;
• regularly weed the rose garden;
• when planting, observe crop rotation;
• carefully select seed;
• feed garden crops, following the recommendations of specialists and taking into account the initial state of the soil;
• choose mildew resistant varieties of roses;
• sanitize tools.

Prevention does not take much time. In order for the rose garden to remain an adornment of the infield throughout the warm season, one must strictly follow the plan of agricultural measures. Otherwise, the appearance of powdery mildew, its false variety and parasites, for example, aphids, cannot be avoided.

Watch the video: How to: Treat Powdery White Mildew A Complete Step by Step Guide (April 2024).