Recognize, treat and prevent

the essentials in brief

• Rose rust is initially identified by orange pustules on the underside of the leaves. These only turn black later.
• The spores overwinter on leaves, shoots and on the ground. Unless countermeasures are taken, a new infection is likely in the following year.
• Remove infected parts of the plant and put them over the house or Organic waste dispose.
• Spray with horsetail broth for treatment and prevention.

What is rose rust?

Rose rust is a typical rose disease caused by fungi of the species Phragmidium mucronatum or Phragmidium tuberculatum. These fungi remain permanently on a plant that has been colonized and overwinter on it. This means that if you don't control an infestation, it can come back every year.

Like all rust fungi, rose rust is stubborn. Towards the end of summer, numerous permanent spores form in the now black pustules, which are mainly located on the leaves and on woody shoots and spend the winter there. Here they rest until around the end of March, when the new leaves sprout, and they also infect them. In addition, the fungal spores are so fine that the wind spreads them and thus ensures the further spread of the disease. With the fall foliage in autumn, they also hit the ground. Rose rust begins to germinate in rather damp weather and very quickly forms many spore beds.

Recognize rose rust in good time

Rose rust begins on the underside of the leaf

In the early stages, rose rust can only be seen if you look very closely and, above all, examine the undersides of the leaves. For a long time nothing can be seen from above and the rose looks completely healthy, while numerous tiny orange bumps have long since formed on the underside of the leaves. Only in the further course and when the summer camps turn black in late summer, light to blackish leaf discolorations can also be seen from above.

Damage and symptoms

You can recognize an infestation with rose rust by these symptoms:

• orange to orange-brownish, about the size of a pin, mostly on the underside of the leaves
• can occasionally appear on the tops of the leaves as well as on the shoots
• often (usually only later) orange-colored spots on the upper side of the leaves
• Elevations and leaf colors turn blackish-brown in late summer

Heavily infested leaves can turn yellow and fall off.

How to distinguish between soot and rose rust

Rose rust and star soot are both fungal plant diseases that often occur in roses and are sometimes confused with one another. In contrast to the rust disease, however, star soot is a dangerous infection that can quickly lead to the death of the rose. You distinguish the disease from rose rust by these features:

• Leaf spots are yellowish, brownish or black
• isolated and very small spots at the beginning
• typically have irregular and fringed edges
• grow very quickly in damp weather
• Morning dew also favors growth
• Spots get bigger quickly
• Leaf yellows and falls off

To prevent star soot (and other fungal diseases), you should regularly spray freshly made horsetail broth when the leaves begin to shoot. A cycle of 14 days is ideal. Diluted whole milk or sodium hydrogen carbonate are also very suitable for prevention. For this purpose, you can find products on the market on the basis of copper or sulfur.

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Rose rust is relatively harmless

Compared to other fungal diseases, rose rust is a harmless infection that initially only has negative effects on the appearance. It only becomes problematic in the event of a very severe infestation or if it recurs over the years. In this case, the leaves can be completely lost and the rose is weakened. This weakening, in turn, manifests itself in reduced growth and less flowering - the rose produces fewer flowers or even no flowers at all. The rose bush very rarely dies as a result of the severe infestation.

Digression

What other reasons are there for the roses not blooming?

Fighting rose rust successfully - methods and means

When the weather is favorable, the fungal spores spread very quickly and infect other roses in the garden. In order to avoid further spread and infection, you should take countermeasures quickly. Especially in the early stages you can do without fungicides with rose rust, as various home remedies can be used against them just as well. In this section we will explain which these are and which treatment options you still have.

Proven home remedies

Spraying with horsetail broth is very effective against rose rust and other fungal diseases (such as powdery mildew). You can spray these preventively every 14 days from the beginning of budding in mid-March to the end of March or in the event of a specific infection. For preventive treatment, dilute the brew in a ratio of 1: 5 with soft water, for fungus treatment, on the other hand, spray it undiluted.

Recipe for horsetail broth:

• fresh Field horsetail collect
• Chop 500 grams very finely, then the ingredients are better flushed out
• alternatively, use 150 grams of dried herb
• Let it steep in five liters of soft water for 24 hours
• then simmer for half an hour at a low temperature
• Let cool and strain

Fill the fresh brew into a spray container and spray your roses with it. In particular, treat the undersides of the leaves, they must be dripping wet. It is best to spray in the early morning on a warm day so that the moisture can dry quickly.

You can also make fern or garlic broth in the same way, which are also great for combating or controlling. Prevention of rose rust is suitable. For the fern broth, you should use eagle or Worm fern collect, both often grow like carpets in damp mixed forests. For the garlic broth, use whole cloves of garlic, including the skin and leaves, not just individual cloves.

Biological and chemical sprays

The use of fungicides is generally not advisable

Various fungicides are commercially available that can be used in the event of an acute attack with rose rust. But be careful: Do not use these agents repeatedly and over and over for weeks, otherwise the fungi will become resistant to them. You should therefore change the active ingredient group regularly. These sprays, for example, are approved for the hobby garden:

• Compo Ortiva (contains azoxystrobin)
• Fungisan rose and vegetable mushroom free (contains azoxystrobin)
• Compo Duaxo (contains difenoconazole)
• Celaflor Rose Mushroom Free Saprol (contains triticonazole)

You must not inject the first two and the last two products one after the other, as they each belong to the same group of active substances. Also, you should only carry out the treatment with fungicides until the beginning of flowering, as the ingredients affect bees and other beneficial insects.

In any case, you should carefully consider the use of fungicides and only use them when there are no alternatives. These agents have significant side effects not only on the ecological balance - they are simply highly toxic and should therefore be avoided if possible. However, it is better (if not optimal) to use sprays such as copper or sulfur. These are also approved against a large number of fungal plant diseases in organic farming.

Further measures

If you discover the characteristic pustules on the rose petals, act immediately. The first thing to do is to do these tasks:

• Remove any infected leaves.
• Cut back the infected shoots and twigs.
• Pick up fallen leaves from the ground.
• If the infestation is severe, remove the top layer of soil.
• Fungal spores can also hide here.

All parts of the plant and the soil removed belong in the household or organic waste. Under no circumstances should you leave them in the garden, as the fungal spores will spread further from here. Further treatment only takes place afterwards.

Effective prevention against rose rust

In any case, careful prevention is better than applying toxic pesticides in the home and hobby garden so that rose rust does not appear in the first place. These measures will help you to prevent infection in the first place:

• Location: Roses feel comfortable in sunny, airy locations with humus-rich, loose soils.
• Plant spacing: When planting, make sure that there is sufficient spacing between the plants, as fungal diseases can spread more easily in overly narrow plantations.
• Regular pruning: Regular pruning makes sense for the same reason, because moisture dries faster in loose, airy crowns and bushes. This will reduce the risk of infection.
• Spring cut: Roses are generally cut when forsythia blooms. Take this opportunity to remove infected shoots and twigs so that the new leaves do not even come into contact with the spores.
• fertilization: Fertilization with a strong emphasis on nitrogen makes the plant material soft and thus susceptible to the penetration of fungal and other pathogens. Fertilize You are therefore balanced and save with nitrogen. Potassium, on the other hand, is good because this nutrient strengthens the cell walls.
• to water: In dry seasons - especially in spring and summer - you should keep the soil evenly moist, as drought weakens the rose. Always water directly on the ground and never over the leaves - damp leaves are a source of infection!
• Mulching: Mulching Cut the root slice with chopped wood in autumn Horn shavings(€ 32.93 at Amazon *) or humus-rich potting soil. This will prevent fungal spores on the ground from reaching the plant after all.
• leaves: Remove the autumn leaves and dispose of them.

Infected clippings and fallen leaves do not belong on the compost, as the temperatures here are usually not high enough to reliably kill the fungal spores.

Plant resistant rose varieties

If you want to be on the safe side and avoid fungal diseases, you can plant so-called ADR roses in the garden. These are modern breeds that have been tested for resistance to the common ones over the years Rose diseases Rose rust, mildew and soot rope have been tested and have proven to be particularly resistant. But be careful: Resistant does not mean that these roses are completely free from fungal diseases can get sick - of course they can anyway, even if an infection is less likely is.

So, in addition to the ADR varieties, you should take preventive measures. An optimal location as well as a balanced fertilization and water supply help to avoid a fungal infection. In wet summers, of course, an outbreak can still occur: avoid using Fungicides, as the fungi become resistant to them, change their genetic makeup and therefore the ADR varieties are no longer resistant to their attacks are safe. Their genetic makeup does not adapt to the changed fungal pathogens.

frequently asked Questions

Are there any other plants that are attacked by rose rust?

Rose rust only affects real roses

The fungal disease rose rust only affects real roses, no other plant species. However, there are a number of other rust fungi, each of which specializes in certain host plants. They all have the typical pustules in common, and the different varieties are similar in terms of the further damage and the measures to be taken to control them.

Which diseases are still common in roses?

Roses are generally prone to various fungal diseases. In addition to rose rust, they are often attacked by powdery mildew and star soot, although some varieties are less sensitive to the infections mentioned than others. Those who plant ADR roses choose proven and resistant varieties.

Why do roses get rose rust at all?

Like so many fungal diseases, rose rust is also transmitted through the air. The microscopic spores reach the plants with the wind and distribute themselves on the roses within a very short time. Sometimes the disease is transmitted through newly purchased roses and planted in the borders if they were sick when they were bought. An infestation cannot always be determined in the early stages of the disease.

Is rose rust also dangerous for humans?

The rose rust is annoying for humans, but completely harmless. It is a pure plant disease that affects neither humans nor animals. However, you should refrain from eating roses that have been infected with mushrooms - the mushroom poisons they contain could at least in allergy sufferers corresponding symptoms such as a rash cause.