Black spot on roses treatment. Black spot on roses

Black spotting of roses. How to identify a disease and cure a plant. How to prevent infection. How to protect yourself from infection (10+)

Black spot of roses

The material is an explanation and addition to the article:
Plant diseases - overview
The plant is sick. How to determine the disease? Types, types, classification of plant diseases and pests. Treatment tips

Black spot- the same common disease of roses as a cold for a person. It is very common; few varieties of roses are immune to this disease. The disease becomes obvious around July, but some species can become ill even in the spring.

Black spotting is caused by spores of a fungus from the genus Septoria, Marssonina rosae; plants can even become infected with contaminated pruning shears. When spores get on a plant, they colonize the leaf and are visible as dark brown spots, then the fungus quickly multiplies, the leaf turns yellow and dies.

Leaves and shoots must be destroyed by burning, because the spores can easily overwinter in the soil and infect the plant again in the spring. Everyone who has planted roses on their property should take care and be kind to them, because this plant is very delicate.

Try to select the most resistant varieties of roses, because some varieties are genetically predisposed to this disease, and it will be difficult for you to fight it. The location of planting your roses also matters - in dense, shaded places where moisture will evaporate longer, you should not plant bushes, the disease will spread faster there.

• An effective method of combating fungal and bacterial diseases, including spotting of various natures

Trimming

Each of us knows that prevention is better treatment. Let's start with the fact that the first prophylactic– pruning. A properly pruned rose will be stronger and more resistant to disease than a rose with depleted and damaged shoots. Non-adapted varieties should also be treated according to the following scheme: the first time - as soon as the leaves bloom and after about a week, before flowering, with a solution of Oxychoma or copper sulfate.

In rainy and cool weather, you should find time to trim the bushes, remove weeds and fill the soil around the rose, as well as treat with biological products such as Alirin B, Gamair, mancocerb-, penconazole- and triazole-containing preparations in order to preserve your delicate garden decoration. A bush affected by black spot almost completely loses its leaves. Most roses cannot survive the attack of this enemy, grow new hair, and die.

After the end of winter, with the onset of warm spring, we often assure ourselves that the rose is simply still in “hibernation”, a little more, and it will delight us with its leaves, and later – flowers. But, in fact, the bush was most likely sick. This fungus destroys many more roses in winter than in summer.

Treatment methods

Treatment for black spot infection is to remove all infected shoots, leaves and other parts of the bush, spraying with copper-containing fungicides, preferably alternating them. There are 3 types of drugs: systemic, contact and contact-systemic. Contact and systemic-contact - copper sulfate, hom, active copper, that is, all copper-containing “medicines”, they destroy fungal spores, but these drugs do not always help in the fight against black spotting.

Systemic and contact-systemic “medicines” - Acrobat, MC, Ordan, Profit Gold, Fundazol, Skor, have the ability to treat the plant from the inside, penetrating through the tissues. But you cannot use the same fungicide, because... mushrooms tend to get used to it. It is for this reason that you should alternate medications and not overdo it, use them no more, no less, but as indicated in the instructions.

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If there are black spots on the leaves of a rose, what should you do? The process of growing roses is impossible without obstacles. The most frequent illness plants are spotty. The disease is very dangerous for the flower, as it leads to its death. When spotting appears on roses, you should immediately begin to combat it. How to avoid spotting on roses? Black spots on roses not only spoil the aesthetic appearance flower, but also cause a lot of harm to the plant. Gradually, the disease spreads throughout the bush and can affect nearby ones. The disease is insidious and difficult to cure. The best remedy- this is the prevention of black spotting on roses. How to prevent the disease from appearing: regularly correct pruning plant stems, since “clipping” increases the resistance of roses; remove damaged leaves, buds, flower stems and be sure to burn them in an area away from the bush; constant weeding of the root area; during the rainy season, sprinkling the soil around the bush with ash has a beneficial effect; treatment of the plant by special means protection for roses; spraying bushes with infusion of mullein or horsetail; correct selection of a site for planting roses: do not plant in darkened and dense areas; frequent treatment of tools with disinfectants. It is also important to know that there are varieties of roses that are more resistant to black spot. Some, on the contrary, are genetically predisposed to it. Therefore, purchasing planting material this needs to be taken into account. How and with what to treat spots on rose leaves? Currently, specialized stores have a huge selection of drugs that can cure spotting. The main thing is to buy not one product, but several. Special drugs should contain: triazole; mancozeb. They will need to be used alternately to be effective. For the first seven days, rose bushes are sprayed with preparations that include mancozeb. For example: “Gold” or “Profit”. A week later, they begin to use products containing triazole, such as Topaz or Skor. Bushes need to be processed in evening time so that there is no presence of dew. Before disinfection, it is worth watering the plant under root system. After the spots on the leaves of the rose disappear, you need to carefully inspect the flower. If the symptoms of the disease recur, it is worth removing the damaged areas of the plant and burning them. Preventative agents Black spots on rose leaves begin to appear only at the end of summer, and damage to the plant occurs at the beginning. Often, a disease attacks a flower if it is weakened or does not receive the required dose of nutrients. Therefore, it is important to fertilize roses. How to determine black spot: firstly, the plant stops growing; secondly, dark spots (like pads) appear on the greenery; thirdly, yellowness is visible around the leaves. Some experienced gardeners use environmentally friendly methods to combat the disease. The area where roses are grown is surrounded by garlic plantings. This vegetable has the ability to prevent fungal diseases(black spot belongs to the genus of fungus Marssonina rosae). Also, for prevention purposes, you can spray the bushes with decoctions of garlic or tobacco. Infusions are not addictive to the infectious agent and do not harm the plant. Proper care It is very important to regularly prune roses. This process will strengthen the plant’s immune system to fungal diseases, which include black spot. Also, if black spots have already appeared on the leaves of the rose, then it is worth cutting off the shoots at the level of 2-3 buds from the base. Then spray the bushes with chemicals (“Copper Oxychloride”, “Vectra”, “Cumulus”). It is better to remove all weak, old and dry branches, because they will be the target of black spot. In autumn and spring, you need to treat the stems with copper sulfate and Bordeaux liquid. All damaged leaves dry quickly and then fall off. They must be collected and burned. Otherwise, the fungus will overwinter and spread to healthy rose bushes in the spring. During the growing season, the plant requires free access fresh air, do not plant other crops too close. Do not allow moisture to remain on rose leaves for a long time. To do this, you need to trim the shoots and weed the weeds. It is better to dig up the surrounding area regularly and add a fungicide (disinfectant) to the soil. The spread of the disease is facilitated by temperature changes and high humidity. But not only environmental conditions can lead to black spot damage to the rose, as well as improper agricultural practices. Therefore, before you grow these flowers, you need to ask how to properly care for them.

This time we invite you to find out about unconventional methods protection against well-known diseases typical of many diseases, as well as highly specialized diseases of roses.

The occurrence of diseases in roses is facilitated by unfavorable weather(for example, wet summer or a long dry and hot period), low lighting, dense plantings and poor ventilation of the rose garden, mechanical damage to plants, etc.

Generally infectious diseases in roses can be caused by pathogenic fungi, viruses and bacteria.

Infectious burn, or stem cancer of roses.

In spring, brown spots with a depressed surface and thickening edges may appear on last year's rose shoots. The spots dry out, the shoot bark cracks, the rose shoots die above the affected area - these are signs of an infectious rose burn. An indispensable condition To avoid infectious burns, cover roses for the winter in dry weather. In the fall, before covering the rose, you need to cut out unripe shoots and burn them, and tear off the leaves from the bush.

To prevent stem cancer of roses it is necessary:

• Avoid excessive application of nitrogen fertilizers to plants;
• fertilize roses potash fertilizers to strengthen shoot tissue;
• cover roses in a timely manner and ventilate bushes during winter thaws;
• remove rose covers in a timely manner in spring;
• trim and destroy shoots affected by cancer.

Powdery mildew on roses

This is one of the most dangerous and common infectious diseases of roses. First, a white cobweb or powdery coating appears on roses affected by powdery mildew. Then the mycelium thickens, the coating becomes brownish-gray. Fungal spores form throughout the summer and are carried by the wind over long distances. The leaves of roses with powdery mildew curl, and the affected areas of the shoots die. Such roses weaken and may die during wintering.

The development of the disease is facilitated by excessive fertilization of roses with nitrogen, calcium deficiency in the soil, lack or excess of moisture, and dense plantings. Roses with leathery or glossy leaves are resistant to powdery mildew.

In the fight against powdery mildew you need to combine correct agricultural technology(strictly monitor the diet of roses, avoid excess nitrogen fertilizers before budding, feed roses during this period with phosphorus-potassium fertilizers; to increase the size of flowers, it is advisable to feed with Baikal EM1 and Gumistar) using fungicides (antifungal drugs) at the first signs of the disease.

Folk remedies for prevention. To prevent infection from being introduced into the garden, purchased roses should be dipped headlong (for 15-20 minutes) into a solution of Copper sulfate (1%) and then regularly carried out preventive maintenance by spraying with one of the following preparations:

Infusion of mullein (1:10);

Five-day infusion of ash (1 glass per 10 liters of water);

Potassium permanganate solution (2.5 g per 10 liters of water);

A solution of soda ash and soap (40-50 g of soda and 40 g of soap per 10 liters of water).

Modern means of prevention. Increased resistance is facilitated by the application of microfertilizers, for example, Aquadon-micro, and the use of immunomodulators, such as immunocytophyte, Narcissus. The destruction of cells of harmful fungi is facilitated by enzymes contained in Gumistar. Fertilizing plants with Baikal EM1 and organic fertilizers based on it.

When appearing on roses powdery mildew it is necessary to immediately treat the affected plants with one of the fungicides such as Fitosporin (biol.), Alirin-B (biol.), Bordeaux mixture (1%) (chemical), or a solution of copper oxychloride (0.4%), or copper soap solution (20-30 g of copper sulfate and 200-300 g of soap per 10 liters of water). If possible, for environmental reasons and to preserve your own health, try to use biological products. Long-term use of copper-containing fungicides can lead to its excessive accumulation in the soil, that is, in quantities harmful to plants.

Rose leaf spots.

At the beginning of summer, especially when it is cool and rainy, brown spots may appear on the leaves of roses, which gradually merge and turn black. Round or oblong swellings appear on the black spots. The affected rose leaves turn yellow and fall off, the bushes become bare - the immunity of the roses decreases, the plants weaken and subsequently grow and bloom poorly.

Except black spot leaves, brown spotting (brown spots with a black border) and white spotting (white spots with a dark red rim) may occur on the leaves of roses - these diseases are provoked by heat and air humidity.

Affected by spots, fallen leaves of roses should be collected and burned, and then the same measures should be taken as against powdery mildew.

Mulching the soil in the rose garden with mowed chopped grass inhibits the spread of leaf spot on roses. Roses with glossy leaves are less susceptible to spotting

Dark spots on rose leaves indicate fungal diseases.

The photo shows a rose leaf affected by black spot. Similar symptoms are observed with purple spot, septoria, and cercospora.

Treatment will be the same in all cases. Its main component is the proper preparation of roses for winter, due to which the infestation of plantings is reduced, the resistance of roses is increased and it is not necessary to apply too often chemicals protection.

- In September, be sure to feed the roses with potassium-phosphorus fertilizers. Potassium reduces the susceptibility of roses to fungi.

- In mid-autumn, preparing roses for shelter, cut off all unfallen leaves and severely affected parts of shoots, carefully collect all debris and burn, dig up trunk circle, then spray the roses with a solution of iron sulfate (3%).

-In the summer, when dark spots first appear on the leaves of roses, spray them with preparations containing mancozeb (Profit, Ridomil Gold) or triazole (Skor, Topaz). For most varieties, if autumn hygiene measures are carried out well, such treatments are rarely required.

Roses have rust.

Dry and hot weather contributes to the occurrence and spread of rust in roses. On the underside of the leaves, on the petioles, sepals and fruits of a diseased rose, orange-rusty pads of summer fungal spores appear. By early autumn, the rust fungus produces winter black spores on the undersides of the leaves. Rose leaves affected by rust turn yellow, die and fall off; shoots are stunted in growth.

At the first signs of rust, diseased roses are sprayed with Bordeaux mixture (1%), if necessary, repeating the spraying after 10 days. Also, when rust pads appear on roses, you can periodically spray the plants with copper oxychloride or a copper-soap solution (after 10 days).

Fallen leaves affected by the fungus are collected and burned. In autumn and spring, diseased shoots of roses are cut off and destroyed, and the soil in the rose garden is dug up. In spring, bushes and soil around roses are sprayed with a solution of Iron sulfate (3-5%).

Downy mildew (caused by fungi of the genus Peronospora, Plasmoparma, etc.) is easily confused with the previous disease. The difference is that with downy mildew, mainly the underside of the leaf is covered with a white fluffy coating of fungal spores. And on the upper side of the leaves you can see light or yellowish spots. Downy mildew spreads primarily through wet leaves.

Control measures. In diseased plants, the affected shoots, leaves, and buds are removed, and the plant is treated with a fungicide, for example, Planriz, Fitosporin, Alirin-B.

Gray mold or botrytis in roses.

The causative agent of gray mold is the fungus Botrytis cinerea, which affects about 200 various types plants. In roses, botrytis mainly affects buds with pedicels, the ends of young stems and leaves; in wet weather they become covered with a gray fluffy coating. First of all, this rot attacks weakened roses, and most often those with white and light pink flowers. The buds on roses affected by botrytis do not open, rot and fall off. Small brown spots (ulcers) appear on the petals, the leaves turn yellow and also fall off. Gray rot also affects young roots of cuttings.

Foci of infection are preserved in plant debris in the form of mycelium (mycelium), which forms spores in the spring. The fungal spores are then spread by insects and wind. Therefore, an undesirable “neighbor” for roses is, for example, garden strawberries, often suffering from botrytis.

Control measures. Preventive measures are the same as for other diseases. As a therapeutic measure, treatment with one of the fungicides will be required. At the initial stage of the disease, the biological product Alirin-B will help.

The appearance of black spots on rose leaves is an alarming signal. If the plant is not treated, it may completely lose its decorative properties, and in severe cases, die.

Causes of black spots on roses

Rose is very whimsical. If there are errors in care, its leaves, and sometimes shoots, are affected by the fungus Marssonina rosae, the causative agent of black spot (BL). After powdery mildew, this is the most common problem with roses. It is easy to determine the emergency: first, brown round spots with a yellow border form on the lower leaves, then they turn black, their shape spreads out like a blot on a blotter.

Black spotting is a dangerous disease that requires immediate treatment.

The disease most often develops after the end of the first wave of flowering against the background of:

• damp, windless weather;
• unsuccessful planting of a rose in the shade;
• the presence of last year's foliage on the soil;
• the density of the bush itself and the plantings around it;
• excessive watering;
• overfeeding with nitrogen fertilizers.

Over time, the disease takes hold and upper tier, the affected leaves turn yellow and fall off. A rose that is sick with an emergency becomes so weakened that it can freeze out in winter.

With heavy rainfall and lower night temperatures, roses are affected by a variety of fungal diseases

Black spot treatment

Urgent measures will help save the plant. First, diseased, drying leaves are removed from the rose, green ones are left, they are necessary for photosynthesis. Fallen leaves are removed, the ground under the bush is sprinkled with ash. Plant residues are burned, they cannot be put into compost, as fungal spores remain on them.

In case of severe damage, when the emergency affected half the bush, chemical preparations containing copper are used: Bordeaux mixture, HOM or Oxychom. Treatments are carried out in the evening every 14 days in the absence of precipitation and once every 7 days in rainy weather until the plant is healthy. The top and bottom sides of the leaf are sprayed.

Many experienced rose growers use the drug HOM for the treatment and prevention of any rose diseases

On early stages Drugs containing triazole are effective in emergency situations:

• Byleton;
• Speed;
• Topaz;
• Tilt.

Fungicides penetrate fungi and disrupt their growth, but they are powerless against germinating spores. Therefore, the listed drugs are alternated with chemicals containing mancozeb, which inhibits the maturation of spores:

• Ridomil Gold;
• Metaxyl;
• Ordan;
• Profit.

Spray the plants with the above products alternately once a week. Usually 3-4 treatments are enough to suppress the emergency.

Fungicide Ridomil Gold is often used for diseases of roses, grapes, fruit trees and tomatoes

At mild form In an emergency, when only 2–4 leaves are affected, you can limit yourself to Fitosporin: 4 treatments every 5 days.

If at least one rose in the flowerbed is sick, you need to spray all the other bushes too.

How specialists treat emergencies - video

Prevention of fungal diseases

Victory over a state of emergency is a temporary phenomenon. The fungal spores are carried by the wind and will again try to settle on the roses. It is realistic to only reduce the likelihood of disease by increasing the immunity of plants with the help of proper care.

• plant varieties of roses that are immune to emergency situations, for example, modern hybrids from Kordes;
• treat new seedlings before planting with beneficial bacteria, for example, the biological product Fitosporin-M;
• add three-year-old humus or compost to the soil to improve the microflora around the bush;
• lime if necessary, too acidic soils promote the development of fungal diseases;
• maintain sufficient distance between bushes for good ventilation;
• promptly prune weak shoots that thicken the bush;
• in the spring, spray with copper or iron sulfate before the buds open, and in the fall - before covering the roses for the winter;
• for prevention, treat roses with biological products or fungicides against spotting during the summer;
• feed the bushes with potassium in early June and potassium-phosphorus fertilizers in August;
• Trim and burn rose foliage completely before winter covering.

Gradually, rose growers are moving away from mono-plantings of roses and planting plants in the neighborhood that are resistant to fungal diseases: lavender, sage, marigolds.

In the second year after planting the rose garden, many of my bushes became infected with black spot. As it turned out, there is no need to feed roses with nitrogen fertilizers in the spring if they were introduced into the planting hole at autumn planting. Overfed roses will always develop fungus.

Very good results This year I got it by hilling roses with old compost for the winter. This procedure significantly increased their immunity. In May and June I carried out preventive maintenance: I sprayed the roses with the fungicide HOM, and in July with Skor. There are almost no diseases, despite the rains. I remove all the leaves from both sick and healthy roses in the fall.

Varieties of roses resistant to black spot - photo gallery

Variety Sympathie - winter-hardy rose, often grown as climbing variety Augusta Louise - profusely blooming hybrid tea rose Westerland variety is the best bush rose Yankee Doodle variety - hybrid tea rose with flowers that change shade

Rose, like a real queen of the garden, requires constant attention. Except proper watering, timely fertilizing, summer, spring and autumn pruning, they must be protected from various diseases and prevent pest invasions.

Among many problems, black spotting of rose leaves comes first. It is impossible to get rid of this disease; it appears on rose bushes every year to varying degrees.

What kind of disease is black spotting?

The cause of this disease is Marssonina rosae, a fungus that can be found anywhere and everywhere where roses grow. For the time being, it can be in a state of rest until certain conditions occur - high humidity ambient air, accompanied by low temperature. In this situation, fungal spores begin to become active and infect the leaves of roses. At the same time, they are spread to other bushes with drops of water from rain, when watering or with dew.

The disease is promoted by:

• Dense planting of rose bushes when the wind cannot dry the leaves after watering, dew or rain.
• High doses of nitrogen in the soil, which are applied in the form of fertilizing. This reduces the plant’s immunity, since nutrition for any plant must be balanced. A deficiency or overdose weakens roses. If a lot of nitrogen has been added to the soil, then it is necessary to add phosphorus and potassium.
• Wrong in the spring.

The first signs of the disease appear as dark, uneven spots on the leaves of the rose, which quickly cover the entire leaf blade, after which it curls, dries out and falls off.

Dormant spores of the fungus also enter the soil along with the leaves.

If in spring and early summer black spot of roses does not manifest itself in any way, then in the middle of summer it can affect all rose bushes and, believe me, this is not a very beautiful sight. The plants stand completely naked. It gets to the point where there is not a single leaf on the bushes. Of course, roses will grow leaves again, but at the same time they spend their energy growing new leaves when they need to prepare for winter. Therefore, not all plants emerge from hibernation, and the cause here may be just such a disease, and not freezing of the rose.

Prevention of black spotting in roses

It is easier to prevent any disease than to treat it for a long time. Everyone knows this, but not every rose lover uses prevention methods in their flower garden. First of all, it is necessary to focus on the fact that not all roses are equally susceptible to this disease. When purchasing, you need to choose those varieties of roses that are most resistant to this disease.

All fallen leaves should be immediately removed from under the rose bushes so that as little fungal spores remain in the soil as possible.

Before covering for the winter, roses should be treated against black spot in the fall with preparations containing copper.

At autumn pruning All excess roses must be burned. You should not take risks and place waste from diseased plants in compost heap so as not to breed infection on the site.

Do we do without chemicals?

Periodic spraying of plants with copper preparations or natural infusions will help reduce the risk of rose diseases such as black spot.

When damp and cool weather sets in, it is necessary to prepare the roses by cutting out all the small shoots going inside the bush. Remove weeds and cultivate the soil under roses wood ash, and sprinkle the leaves with a solution of Fitosporin, Gamair, or Alirin B.

Good results are obtained when spraying rose bushes with compositions made from natural products:

• mullein infusion;
• garlic or onion peels;
• horsetail infusion;
• dry wood ash;
• infusion of nettle with dandelion.

Treatment of roses against black spot with a concentrated infusion of mullein is carried out in early spring, there are no leaves yet. After the earthen hill has been moved away from the rose bushes and the cover has been removed. While there are no leaves, there is nothing to burn, but the shoots will survive. They just pour water on all the shoots from a watering can. For prevention purposes, it is recommended to carry out such treatment several times during the summer. But in summer the infusion is diluted with water 1:10. The procedure is not entirely pleasant, given the emanating aromas, but effective, according to many rose growers.

Infusions or decoctions of onion or garlic peels are used undiluted, when the color of the liquid resembles weakly brewed tea. Spraying is carried out at any time, whether in spring or summer.

Black spot of roses preparations

after processing Hom

If natural infusions and decoctions do not bring any benefit, heavy artillery enters the battle in the form chemicals containing mainly copper and fungicides. As a preventive measure, when the weather worsens, supporting plant immunity can be used. To do this, roses are treated with such agents as Tsiovit, Epin, or Epin-Extra.

If black spotting appears on roses, treatment is carried out until it disappears, every 10-12 days. And in order for the plant not to get used to one drug, they need to be changed or alternated. Large selection:

• Oksikhom;
• Profit;
• Ridomil Gold;
• Fitosporin;
• Abiga Peak;
• Thiovit-Jack;
• Topaz or Skor and many others.

Naturally, before using this or that drug, you must carefully read the attached instructions.

Treatment of roses with preparations is carried out until complete wetting sheet plate early in the morning or in the evening, when the rays of the sun can no longer burn the leaves.

After all, each drop acts like a lens, increasing the risk of burns hundreds of times. If the weather is cloudy, you need to count on at least 3-4 hours before it rains. If there are few bushes, you can make a shelter over each one in the form of an umbrella so that the drug does not wash away with the rain.

Usage preventive measures may well protect plants from such a disease, and you will not be faced with the question of black spotting of roses and how to deal with it.