The powdery white sediment covering the aerial part of the roses indicates the development of a dangerous fungal infection on the plants. Powdery mildew can quickly spread to neighboring plants. If treatment is not started, the affected rose bushes will begin to fade and may die.
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Symptoms and Dangers
Ectoparasitic fungi from the order Erysiphales cause the development on the stems, leaves, buds of an infection called linen, ash, as well as powdery mildew.
The main feature is a sediment formed by a powdery white mycelium. After the end of the ripening period of the spores, droplets of liquid appear on it. Gradually, plaque captures the entire aerial part of the plant, making photosynthesis difficult.
Affected buds and foliage turn yellow prematurely, wither, and then fall off. The plant weakens, stops developing. Without treatment, it dies over time.
The reason for the trouble is the lack of lighting, dense planting of rose bushes, insufficient aeration of the soil, sudden changes in humidity and temperature, excessive application of nitrogen nutrients, lack of soil calcium.
Preventive measures
The appearance of powdery mildew on roses can be prevented if a number of measures are taken in a timely manner:
- Cultivars are selected that show high resistance to fungal infection. It could be Aphrodite, Halle, Cadillac. Gloria Day, Crocus Rose, Rosoman Zhanon are developing well. Recommended by Summerson, Pearl Tiger, Westminster Abby, etc.
- For planting, select a place with sufficient lighting and well-drained soil.
- Do not allow excessive density when placing pink seedlings.
- Collect plant residues in a timely manner. It is recommended to burn them.
- Observe the norms and order of fertilization.
- Powder roses three times during the entire growing season with sifted ash.
- Watering is practiced in the morning. Do not allow waterlogging of the soil.
- For the purpose of prevention, the rose garden is irrigated with "Fitosporin-M".
Ways to fight
Having noticed the characteristic mealy bloom, you need to cut and burn the stems with signs of infection.
Several activities are performed:
- Tear off old leaves at the bottom of the stems.
- Regulate watering, excluding excessive soil moisture.
- The top soil layer is carefully removed and fresh substrate is poured in instead.
- The plantings are irrigated with Bordeaux (1%) liquid. It is possible, with the initial signs of powdery mildew, to use a solution (0.4%) of copper oxychloride.
- If the fungal infection has invaded a large area, more effective fungicides will be required, for example, Skor, Chistotsvet, Topaz. Also used by Previkur Energy, Tiovit Jet, Rakus.
They practice medicinal spraying not only of the aboveground part of the roses, but also of the soil under them. On average, 2-3 procedures are required, between which an interval of 7-10 days is maintained.
Folk remedies
It will be possible to do without chemical varieties at the stage of preventing the development of powdery mildew or at the first minor signs of a dangerous fungal infection. Folk remedies will not show the expected effectiveness if the disease is already running and covers almost the entire plant.
Several options are used:
- Soda infusion
The heated water (4 l) is poured into a suitable container. Dissolve with vigorous stirring 1 tbsp. l. soda (use a soda ash or drinking variety) and 0.5 tsp. l. liquid soap. The cooled solution is sprayed with the rose garden 2-3 times at weekly intervals.
- Ash infusion
1 kg of sifted ash is poured into a 10-liter container with warm water. With systematic stirring, incubate for 3-5 days. Liquid soap is dissolved in the expressed infusion (0.5 tsp. l.). Used for spraying. You can water the affected bushes, but in this case add another 10 liters of settled water to the prepared liquid.
- Mustard infusion
You will need hot water (10 l), in which 2 tbsp is thoroughly stirred. l. powdered mustard. The cooled infusion is used for watering or irrigation of roses affected by the fungus.
- Garlic infusion
The cloves of garlic need to be finely chopped or grinded. Measure 30 g of the resulting slurry, transfer to a bottle or jar with 1 liter of water. A day later, the infusion is filtered and a spraying operation is carried out.
- Potassium permanganate solution
Pharmaceutical potassium permanganate will be required - 3 g. The powder must be diluted without residue in 50 ml of water. Then the concentrate is poured with constant stirring into a 10-liter bucket of water. With this solution, roses can be watered or watered.
- Serum
Serves not only the prevention of powdery mildew, but also has a beneficial effect on the development of plants solution, for which the serum is combined 1:10 with water. Spraying roses is practiced immediately.
- Manure
It is necessary to use well-rotted manure, which is diluted 1: 3 in water. After 3 days, the same volume of water is added to the expressed infusion. Used for spraying.
- Horsetail decoction
Fresh horsetail grass (100 g) is crushed and left for a day in a liter of water. Then the mixture should be boiled at a low temperature for 55-60 minutes. The cooled broth is filtered. Before spraying, dilute 1: 5 with settled water. The concentrate can be kept cool for about a week.
Peronosporosis
The rosary can be affected by downy mildew. Known as peronospora, this infection is caused by pseudo-fungi mainly from the Peronosporaceae family.
The main feature is yellowish or reddish-brown markings on the upper plane of the leaves. On the seamy side, brownish-gray influxes with a characteristic mealy bloom appear. The leaves wilt and then die off. The growth of plants slows down. With extensive infection, they die.
The reasons for the development of infection, as well as prevention and control methods, are identical to the measures practiced when powdery mildew appears.
When growing roses, it is important not only to follow agricultural techniques. It is necessary to carry out preventive treatment of plantings in order to prevent the development of a dangerous fungal infection. At the first symptoms of powdery mildew, you should immediately use a suitable plant treatment.
Do you know how to protect roses from dangerous powdery mildew?
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