Powdery mildew on roses: what it looks like, treatment, control measures, what to spray with

Powdery mildew on roses is the most common fungal disease of this crop. It causes serious damage to the plant and can cause death if not treated in a timely manner. But not all gardeners know how to recognize the first signs of damage and what to do in this case. Therefore, you should familiarize yourself with the characteristics of the fungal disease, find out what drugs will help save roses from powdery mildew, and also what preventive measures reduce the likelihood of occurrence on roses.

Fungal disease prevents full flowering and development of the bush

What does powdery mildew look like on roses?

The disease can be recognized by a white coating, which is the sporulation of the fungus. When erased, it remains on the fingers, and at the same time there is an unpleasant herring smell. Initially, powdery mildew appears on the upper side of the leaves in separate spots. Subsequently, they grow and merge into a single whole.

Under favorable conditions, the disease actively progresses and eventually spreads. In addition to leaves, it affects shoots and buds of roses. After the spores mature, small drops appear on top of the plaque, which fully justifies the name of the disease.

Important! Powdery mildew begins to progress in late spring or the first half of summer.

Subsequently, the white coating becomes dirty gray and then brown. And on the affected areas of the leaves and shoots of the rose, small dark brown spore balls appear.

What is the difference between powdery mildew and downy mildew?

Another common fungal disease of roses is downy mildew (pictured below). At the initial stage of development, it can be recognized by yellow-green round or angular oily spots, which are limited by leaf veins. On the reverse side of the plates, a purple-gray coating appears in this place.

As a result, the lesions grow and merge into a single whole. Downy mildew is characterized by a rapid development process. And if yesterday the rose bush looked quite healthy, today it may already have a depressing appearance.

Important! The difference between downy mildew is that the disease begins to develop from the top of the bush, and not from the lower leaves located towards the ground, as in a real infection.

Without treatment, the rose may die from downy mildew.

Reasons for appearance

The causative agent of the disease is the powdery mildew fungus Sphaerotheca pannosa, as a result of which active sporulation causes the leaves, buds and shoots of the rose to become covered with mycelium. It appears in the form of a white thick coating, which fully justifies the name. The pathogen overwinters in microcracks on the stems and under the scales of dormant buds. With the arrival of spring warmth, the fungus begins to actively develop. This is facilitated by a temperature of + 25 ° C and above in combination with humidity in the range of 70-90%.

Important! Powdery mildew most often affects hybrid tea and climbing repeat-blooming roses.

However, the disease can also develop in the event of prolonged drought. During this period, rose leaves lose turgor, which facilitates the penetration of fungal haustoria into plant tissue. Therefore, watering and a constantly slightly moist substrate are the main conditions for the prevention of this disease.

Provoking factors for the development of powdery mildew on roses:

Long rains followed by warm weather. These conditions contribute to the active evaporation of moisture from the soil.
Sudden changes in day and night temperatures.
Closely planted rose bushes. Insufficient ventilation contributes to the active growth of fungus.
Failure to comply with the feeding schedule. Excess nitrogen in the soil leads to excessive growth of green mass, which weakens the immune system.
Heavy ground. This leads to disruption of air access to the roots of the rose. Against this background, the plant is not able to fully absorb nutrients.

Purchasing an infected seedling can also cause the development of powdery mildew in a rose garden. Therefore, before planting a new bush, it is necessary to initially treat it with fungicides that are effective against this disease.This will minimize risks.

Why is powdery mildew dangerous?

Powdery mildew is a disease of roses that not only leads to a lack of flowering, but can also cause the death of the bush. The development of the fungus disrupts photosynthesis in the leaves. Against this background, metabolic processes in tissues initially slow down and then stop completely. This leads to deformation of leaf plates, shoots, buds, and roses.

As a result of further progression, drying out of the affected areas and premature leaf fall are noted. This leads to a deterioration in the decorativeness of the rose. In addition, powdery mildew significantly weakens the bush’s immunity, which negatively affects its frost resistance.

Not all bushes weakened by powdery mildew are able to survive the winter

How to treat and how to get rid of powdery mildew on roses

The white coating that appears on the leaves only initially looks harmless. But powdery mildew on roses must be combated immediately at the first signs of damage, so as not to waste time and prevent mass spread to all bushes. To do this, you can use professional and folk remedies that can successfully complement each other. But it should be understood that the treatment of powdery mildew on roses must be comprehensive, since one treatment cannot solve the problem.

The best remedies and preparations for powdery mildew on roses

There are a number of chemical and biological preparations that can effectively combat the disease on shrubs. They act upon direct contact with the pathogen, and can also penetrate plant tissue, spreading throughout the entire part.

Important! The disadvantage of professional products is that they can be addictive, so it is recommended to alternate them periodically.

Colloidal sulfur

This drug has proven its effectiveness against powdery mildew on roses for many years. It is characterized by a contact action, and therefore requires uniform spraying of all parts of the bush.

Treatment of roses against powdery mildew with colloidal sulfur should be carried out at a temperature not lower than + 20 ° C, but not higher than + 35 ° C. In the first case, its effectiveness decreases, and in the second, the active component can cause burns on the leaves. To prepare a working solution, add 30 g of powder to 10 liters of water.

Colloidal sulfur cannot be combined with other drugs in the same tank mixture

Tiovit Jet

A sulfur-containing drug in which the mass fraction of the active component is about 80%. The product is effective at the initial stage of the lesion, as it has a contact effect. To get rid of powdery mildew, you need to spray the roses with a working solution of the drug, evenly wetting the parts of the bush. To prepare it, you need to add 30 g of the product per 10 liters of water.

The temperature range for use of Tiovit Jet is +20-35 °C

Score

A chemical preparation of contact-systemic action, the active substance of which penetrates the plant tissue and provides comprehensive protection. It can be used to control powdery mildew on house and garden roses. To prepare a working solution, add 1.6 ml of product to 8 liters of water.

The drug Skor begins to work 2 hours after treatment

Topaz

A chemical preparation of systemic action, which ensures high effectiveness of its use against fungus.The active component initially inhibits sporulation and then causes the death of the pathogen. The duration of fungicide protection against powdery mildew on roses is 10-14 days. To treat rose bushes, you need to dissolve 2 ml of the drug in 5 liters of water.

When treating with Topaz there is no need to wet all leaves and shoots

Fitosporin-M

A biological preparation that can cure a rose from powdery mildew at the initial stage of damage. Its basis is a culture whose waste products suppress sporulation of the fungus. The drug has a systemic effect, so it penetrates into all parts of the plant. Fitosporin-M is a safe drug that can be used without fear even in an apartment. To prepare the working fluid, you need to dissolve 1.5 g of powder in 1 liter of water.

The biological product Fitosporin-M must be diluted 2 hours before use.

Folk remedies for powdery mildew on roses

This method of combating fungal disease can be used at the initial stage of infection. To prepare effective remedies, you can use ingredients that are present in every home. Folk measures to combat powdery mildew on roses can also be used as a preventive measure.

But it is worth understanding that when the disease spreads massively, this treatment method is not able to stop the disease, so in such cases it is necessary to use chemicals.

Baking soda

To prepare an effective product, you need to pour 50 g of this component into 5 liters of warm water. Then grate 30 g of laundry soap and also add to the mixture. After this, mix until a homogeneous composition is obtained. Use the product to evenly spray the bushes.Repeat the treatment of powdery mildew on roses with soda every 10 days until the bush is completely restored.

Milk serum

To prepare the working solution, you need to collect 5 liters of water in a separate container. Add 1 liter of whey and 10 drops of iodine. Mix everything thoroughly. And to improve adhesion, you need to add an additional 30 ml of dishwashing detergent. Use the mixture to spray the bushes immediately after preparation. Repeat therapy every 10-12 days if necessary.

Wood ash

An extract based on this component has a healing effect. To do this, you will need 20 g of wood ash, pour 1 liter of boiling water, cover with a lid and leave for 12 hours. At the end of the waiting period, clean the mixture. Apply the resulting concentrate in a ratio of 1:10 with water. If the rose is sick with powdery mildew, then treatment should be done every 7 days until the signs of the disease completely disappear.

Important! Folk remedies not only treat the disease, but also additionally nourish the bushes.

What to do if there is powdery mildew on rose buds

If signs of the disease appear at the stage of preparing the bush for flowering, then it is necessary to act quickly. However, given that chemicals during this period can cause deformation of the buds and lead to burns, preference should be given to biological products.

In this case, it is recommended to use Fitosporin-M against powdery mildew on roses. It has a gentle effect, so you can use it without fear.

To treat indoor roses, you should use safe drugs

How to treat powdery mildew on roses in summer

During this period of the year, the fungus begins to progress and can spread to all the rose bushes in the garden.Therefore, chemical control agents should be used. It is advisable to carry out treatment every 10 days, alternating medications. The most effective of them: Skor, Topaz. And between the main treatments, you can use folk remedies.

How to treat roses against powdery mildew in the fall

During this period of the year, the bush is already preparing for the winter. Therefore, it is recommended to use sulfur-containing products in the fall. They help fight the pathogen of powdery mildew on plant shoots. Roses should be sprayed against powdery mildew in the fall with colloidal sulfur and Tiovit Jet.

How to treat indoor roses against powdery mildew

To treat a plant at home, preference should be given to safe control measures. Therefore, first of all, you need to use folk remedies. If the disease continues to progress, then it is necessary to use Fitosporin-M. In case of mass destruction, it is worth using Skor, but only in a well-ventilated area.

Measures to combat downy mildew

For treatment to be effective, you must follow some recommendations. Otherwise, therapy may not bring the desired result and cause harm to the plant.

Basic Rules:

Before treatment, you must initially remove all affected leaves and shoots, since they will not be able to recover, but will only be a source of infection.
Do not spray roses after watering or rain. In this case, the leaves are not able to absorb the solution fully, so the treatment will not be effective.
When using folk remedies and contact preparations, it is necessary to spray the shoots and leaves evenly on both sides, otherwise it will not be possible to completely get rid of the fungus.
To save an indoor rose, you need not only to spray the above-ground part, but also to replace the top layer of soil in the pot. After all, this is where the colonies of mushroom mycelium are concentrated.
You need to fight the disease regularly. Therefore, treatment of the bushes should be repeated every 7-14 days until the signs completely disappear. For prevention, you need to spray roses once a month.
The working solution should be prepared immediately before use, since it loses its effectiveness during storage.

It is important to treat bushes in dry, windless weather.

Prevention of diseases

Following simple rules for caring for roses can reduce the likelihood of developing powdery mildew. They are very effective and do not require complex actions.

Prevention measures:

periodically inspect the bushes;
carry out feeding taking into account the stage of development of the rose;
spray plants with fungicides and folk remedies once every 2-4 weeks;
do not allow the root system to dry out;
loosen the soil after watering and rain;
remove weeds in a timely manner.

Rose varieties resistant to disease

Some types of shrubs are more susceptible to powdery mildew. Therefore, in regions with difficult climatic conditions, varieties that are resistant to this disease should be grown.

These include the following types of roses: Lady of Shalott, Aphrodite, Galaxy, Aspirin Rose, Cadillac, Westerland and Gold Spice.

Conclusion

Powdery mildew on roses is a dangerous disease that must be constantly combated. Therefore, increased attention should be paid to prevention, and if signs of damage appear, do not delay treatment.In the absence of timely protective measures, the disease can spread to the entire rose garden and nearby crops. Then it will be much more difficult to deal with it.

How to treat and how to get rid of powdery mildew on roses: preparations, photos