This image was created by user Gerhard Koller (Gerhard) at Mushroom Observer, a source for mycological images.You can contact this user here. German | espanol | french | italiano | macedonian | മലയാളം | portugues | +/−, 2008-05-14 Puccinia malvacearum 60215, crop from Plantopedia, CC BY-SA 3.0
The colorful blossoms of the mallows (Malva), which grow up to three meters high, can set magical accents in the garden from late summer to autumn. These plants are particularly suitable for cottage gardens and wild gardens. Even if the mallows are largely easy to care for and robust, they are sometimes attacked by mallow rust, which must be combated.
Mallow rust widespread
Among hobby gardeners, mallow rust (Puccinia malvacearum), which is widespread worldwide, is a dreaded fungal disease. It can appear in early spring, after the first leaves have sprout. As soon as the first signs appear, immediate action must be taken to prevent the spread of this dangerous fungal disease. This includes
- warty formations on the underside of the leaves
- pustules reddish yellow in colour
- yellow-brownish spots on the upper side of the leaves
As a result of the disease, the leaf tissue eventually turns yellow, later brown. The leaves begin to wither and eventually fall off. If this has already happened, the affected leaves must be disposed of immediately, but not in the compost, but in the residual waste. These pustules on the underside of the leaves contain the spores of the fungi, which are used for reproduction. They can easily overwinter there and become active again next spring. Therefore, disposal is imperative to prevent the fungus from spreading to other plants or in the soil.
Notice: Mallow plants with double flowers are particularly at risk. However, the fungus does not stop at summer flowers, cup mallow, geraniums, silver linden or rose mallow.
recognize causes
The disease is a pillar fungus, which belongs to the order of the rust fungi (Puccinales). This fungus is extremely resistant. The protruding spore beds on the underside of the leaf appear nest-like there. The mycelium of the mallow rust grows into the storage tissue of the affected plants. There, the Puccinia malvacearum feeds on the available plant nutrients and thus extracts them from the plants.
Björn S… , Puccinia malvacearum on Marsh-Mallow - Althaea cf. officinalis (30709427647), crop from Plantopedia, CC BY-SA 2.0
When the spore nests break open, the individual spores are then released and can spread through the air. However, the disease can also be introduced when new young plants are purchased. It is therefore advisable to check them thoroughly before purchasing them. In addition, there are other causes for the development and promotion of mallow rust such as
- a warm, rainy and sheltered location
- too high humidity
- too little plant spacing
- no drying of the leaves after downpours
High humidity and warm weather create an excellent basis for the spread and reproduction of the fungus.
Notice: The mallow rust fungus can overwinter well in the plants and then break out in early spring under suitable weather conditions.
Combat mallow rust biologically
The treatment of affected plants does not always have to be resorted to with chemicals. Action should always be taken in favor of the environment. Fighting the Puccinia malvacearum biologically without any chemicals can be done with one or the other home remedy. Not only milk or baking soda do a good job here, various self-made manure plants can also be used not only to combat but also to strengthen the plants at the same time. Below is a small list of proven home remedies and their use.
Skimmed milk against pathogens
Every child knows that milk is healthy, but not only for people. Skimmed milk, buttermilk or whey can also be used successfully to combat various plant diseases. The lactic acid bacteria contained in the milk take up the fight against the mallow rust fungus. Not only that, at the same time the treated plant receives a small boost in its defenses from the lecithin and sodium phosphate contained in the milk.
However, only low-fat fresh milk, buttermilk or whey should be used for this measure. UHT milk is not really suitable here, since the microorganisms contained in the milk are no longer active and therefore no corresponding effect is achieved.
The application must always be diluted with water in a ratio of 1:8. In other words, 100 milliliters of milk are mixed with 800 milliliters of water. The period of application of the mixture depends on the prevailing weather:
- repeat every 10 days in wet weather
- in dry weather every 3 to 4 weeks
If you want to be on the safe side, you can also spray the milk-water mixture on the plant once a week as a preventive measure.
Tip: Raw milk directly from the farmer or from the health food store is best suited for this.
Soda from the supermarket
Another proven home remedy for biologically combating mallow rust is a lye made from baking soda (sodium bicarbonate). To produce this caustic soda are required
- 1/2 teaspoon baking soda and
- 1 liter of water
For better effectiveness and adhesion to the plant, the caustic soda can still
- 1/4 teaspoon grated curd soap and
- 1 teaspoon cooking oil, such as sunflower oil
be added. The mixture should be heated a little beforehand and then the grated curd soap should be stirred in until it has completely dissolved. Only then is the oil added. The application takes place every two weeks.
Notice: The caustic soda produced in this way is also effective against powdery mildew, blackspot and aphid infestation. In addition, baking soda can be used for numerous other purposes.
Vegetable broth made from ferns
Fresh or dried fronds from worm or bracken are particularly suitable here. The preparation of the brew is usually relatively simple. are needed
- 100 grams of fresh mature fronds
- alternatively 10 to 20 grams of dried leaves
- 1 liter of water
When all the ingredients are available, the preparation of the plant brew can begin:
- Roughly chop the leaves
- then start with stagnant rainwater, if possible
- cover and leave to stand for 24 hours
- then simmer gently for 15 to 30 minutes
- strain, squeezing out plant remains well
- Fill in syringe or spray bottle
With the amount of these ingredients, a 1/4 liter plant brew is created. This is used undiluted. It should be on warm, slightly overcast mornings. applied on windless and non-sunny days. After two to three weeks it is advisable to repeat this measure. The brew is also effective against a plague of snails.
Broth from compost
A spray made from compost is also excellent for combating mallow rust. It should be used especially when Puccinia malvacearum is still in its infancy. is required for crafting
- 0.5 liters of well matured compost
- 2.5 liters of water
Make a porridge from these ingredients. This must last at least a week. In between, the whole thing is stirred daily and roughly filtered after a week. Every three to four days, the prepared broth can then be sprayed directly on the leaves and also on the soil around the plants.
Plant manure made from field horsetail
The silicic acid contained in the plant is not only effective against mallow rust, but also strengthens the affected plant. The acid strengthens the plant cells, making them less susceptible to diseases and pests. However, the required parts of the plant should only be collected until the end of July, as the silicic acid content then decreases. It can be used fresh or dried. You need:
- 300 grams of fresh plant parts
- alternatively 30 grams dried
- 2 liters of water
To produce the liquid manure, the parts of the plant are cut up with secateurs or a sharp knife and soaked in water. Then everything has to
- draw 24 hours
- then simmer on a low flame for 30 minutes
- strain
The liquid manure must be diluted with water in a ratio of 1:5. If the infestation is severe, the plants should be treated daily for three days. A 14-day spray from spring to summer can also be helpful to prevent mallow rust.
Notice: A horsetail broth can also be used against scab, brown rot, gray mold and mite infestation.
Yarrow broth
Such a broth is also good for fighting mallow rust, but also for curling. It also contains a high proportion of silicic acid and potassium. In addition, the plant receives fertilizer and the cell tissue is strengthened. Mainly flowers should be used. These can be collected from June to September and used fresh or dried. are needed
- 200 grams of fresh or 20 grams of dried flowers
- 1 liter of water
The preparation of the broth is done in the same way as the liquid manure from field horsetail. However, the extract must be diluted with water in a ratio of 1:9. Application can be made as needed.
garlic tea
Garlic is not only healthy for humans, but can also be used to combat various plant diseases such as Puccinia malvacearum. this will
- 70 grams of crushed garlic
- poured with a liter of boiling water and
- Leave for 5 hours and strain
The first spraying can be done immediately after the first leaves have sprouted. Another treatment is given after a month.
onion broth
Not to be forgotten is the healing effect of the onion, which can also be used on plants. are required for crafting
- 150 grams of onions or peels
- 2 liters of water
The two ends of the onion are cut off and quartered with the peel. Then the individual slices are divided and placed in a pot together with the peel and the ends of the onions and poured over with boiling water. Everything has to steep for 30 minutes and is then strained. The broth is injected undiluted in the case of an existing disease. As a preventive measure, you can dilute the broth in a ratio of 1:10 with water and use it every 14 days after the budding has taken place. The leaves and the soil are sprayed carefully.
Tip: When fighting mallow rust, you must carefully spray all the leaves on the top and bottom with the respective home remedy. If possible, also the soil around the plant.