Content
Currants, like any crop, can suffer from diseases and pests. Most often, the lesion is in the form of red or white spots. If you do not take measures in time, you can lose the crop and the bush itself. Before treating brown spots on currant leaves, determine the cause of the lesion. Next, choose the appropriate method: folk remedies, the use of chemical or biological preparations.
Why do currants have red leaves
Currant is a berry bush with green leaves. They have 3 to 5 lobes and large teeth. Their leaf plate is smooth and shiny, has a specific smell. When red spots appear, the integrity of the leaves is violated, the plant loses its decorative appearance.
Reasons for the spread of brown or red spots on currants:
- the initial stage of the disease is anthracnose;
- the spread of a fungus that causes rust;
- the appearance of a dangerous pest - red-gall aphid.
In autumn, the color of currant leaves becomes yellow or burgundy. Leaf fall ends in September or October, depending on weather conditions. Reddening of the leaves in autumn occurs due to the change of season. If they change color ahead of time, then this is already an alarming sign for the gardener.
Causes of brown spots on currant leaves
Depending on the cause of the lesion, a treatment method is selected. To accurately diagnose why the leaves of the red currant are covered with red spots, the entire shrub is examined.
Anthracnose
Anthracnose is a disease of trees and shrubs caused by the marsupial fungus. It is distributed in Western and Eastern Europe, America, Russia. The northern and western regions with a temperate climate and frequent rainfall are at risk.
The defeat applies to all types of culture: black, white and red. Brown spots appear on the petioles and leaves of currants. Their size is about 1 mm. Then they develop spores in the form of black tubercles. Black depressed spots are observed on the petioles.
A harmful fungus remains in the fallen leaves for the winter. Infection begins at the end of May. Diseases are most susceptible to leaves that have blossomed 25 - 30 days ago. Currant anthracnose develops at the end of flowering. If you do not take timely measures, then the peak of the defeat will be in July and August.
The fungus grows in moisture droplets. The optimum temperature for its development is from +15 to +20 ° C. Under these conditions, the incubation period lasts 8 - 12 days. On black currants, the disease appears at lower temperatures.
When red spots appear, the development of the bush slows down, which does not receive the necessary nutrition. If you do not start treatment, its frost resistance will significantly decrease. In the spring, the bush can lose half of the shoots.
Gall aphid
Gall aphids can cause spots on red currants. In early spring, its larvae appear, which spread over the plants. They have an ovoid body up to 2 mm long and pale green in color. During the season, up to 20 generations of gall aphids are formed.
As a result of the activity of the larvae, the leaves at the tops of the shoots change color and shape. On currants, red swellings are diagnosed - galls. These are neoplasms that arise as a plant's defense reaction to a pest.
Gall aphid is widespread in Eurasia. The insect is found in both southern and northern regions. After the appearance of red spots on the leaves, the plants give a small increase and yield. Young leaves suffer most from gall aphids. If the leaf plate has already formed, then red swellings do not appear on it. The lesion will take the form of small pinpoint spots.
Rust
Rust is a disease of currants and other crops, which belongs to the fungal group. The first symptoms appear after flowering on shoots and leaves. They look like large round spots of yellow or orange color. Often these spots have a red border. By mid-July, black dots appear on the leaves - fungal spores.
Over time, the red spots swell and become covered with gray growths filled with black spores. The disease is common in the southern regions: in Moldova and in the North Caucasus. Without treatment, red leaves fall off prematurely, the yield of the bush decreases, and the taste of berries deteriorates.
How to process red leaves on currants
For the treatment of currants from red spots, chemical or biological preparations are chosen. They are alternated with folk methods, which are also used to prevent red spots on currants.
Chemicals
Chemicals are most effective against red spots. Before using them, you need to read the instructions. Be sure to observe the dosage. It is best to carry out processing before the beginning of fruiting or after harvesting the berries.
For the treatment of currants, a solution is prepared. It is sprayed over the leaves with a spray bottle. The bush is processed on a cloudy day or in the evening when the sun disappears. Gloves, glasses or a special suit are worn to protect the skin and organs of vision.
If the red convex spots on the leaves on the currants are caused by diseases, then the following means are used:
- Bordeaux mixture... A solution based on lime and copper sulphate. It works against various fungi. The product adheres well to the leaves. For the treatment of red spots on currants, a solution of 1% concentration is obtained. Treatments are carried out no more than once every 14 days;
- Copper oxychloride... Alternative to Bordeaux liquid. Has the appearance of light green crystals. Copper compounds have a detrimental effect on microorganisms. When treating currants, the solution is valid for 10 - 12 days;
- Abiga Peak... Fungicide intended for the treatment of currant diseases. For 10 l of water add 40 ml of the suspension. The working solution evenly covers the leaves and is not washed off by rain. The product is effective at low temperatures, promotes the formation of chlorophyll, and improves plant immunity.
If red bubbles on currant leaves are caused by gall aphids, then they resort to insecticides:
- Aktara... An enteric preparation that is effective in low humidity and high temperatures. The solution is not washed off with water. Spraying is carried out before the buds appear or after the berries are removed. For 5 liters of water, 1 g of the drug is needed. 1 liter of solution is prepared for the bush. The waiting period is up to 2 months;
- Ditox... Systemic preparation for the control of aphids and other insects. Differs in high efficiency. The pest dies a few hours after the treatment of the bush;
- Spark... Effective against various insects. Works even in hot weather. Iskra is safe for humans, animals, birds and beneficial insects. 5 ml of the suspension are added to 10 l of water. Spraying is carried out with a massive appearance of the pest.
After processing the currants from pests, they begin to treat it. The bushes are fed with mineral complexes.In the spring, urea or other nitrogen-based fertilizer is applied. In summer and autumn, a solution is prepared containing superphosphate and potassium sulfate.
Biological preparations
Biological agents suppress the activity of the harmful fungus. Some of them are used at any stage of the growth of the bush. The active substances do not penetrate the plant tissues, do not accumulate in the fruits
The following biological preparations are used to treat red swollen spots on currant leaves:
- Tiovit Jet... Sulfur-based remedy for the treatment and protection of currants from fungal infections. To prepare the solution, 20 g of the substance is required per 5 liters of water. Currants are processed during the growing season;
- Agrohealer... Systemic fungicide to protect the garden from fungal diseases. Spraying is carried out before the formation of buds or after removing the berries. The consumption rate is 10 ml for a large bucket of water;
- Tsikhom... A new drug that provides treatment and protection of currants from fungus. Spraying requires 10 ml of fungicide per 10 liters of water. No more than 1 liter of solution is prepared per bush. Treatments are carried out in early spring or autumn.
Biological preparations against gall aphid:
- Akarin... Insecticide with fast action on insects. After 8 - 16 hours after treatment, the aphid loses its motor activity and dies. The bush is sprayed during the growing season. For 1 liter of water, 2 ml of suspension is required. Re-processing is possible after 2 weeks;
- Fitoverm... Does not penetrate into plant cells and is harmless to humans. For spraying one currant bush, a solution of 1 liter of water and 0.06 ml of suspension is required.
Traditional methods
Folk remedies are used in addition to the main methods of treatment. They are safe for plants and humans. In addition, they are chosen for the prevention of diseases and the spread of insects.
Alternative methods of treating brown spots on red currants:
- Soap... Add 50 g of soap base to 500 ml of water. It is best to use sulfuric or tar soap, which disinfect plants well. They can be added to any natural remedy to keep the solution on the leaves longer;
- Garlic... For 2 liters of water, take 1 cup of chopped garlic cloves. For treatment, the agent is used after 2 days, when it is well infused;
- Iodine... A large bucket of water requires 10 drops of iodine. Mix the solution well and start spraying.
Methods for treating currants from gall aphids:
- Tobacco dust... For 2 liters of water, take 1 glass of tobacco dust. Means are boiled for 30 minutes over low heat. Then add 2 liters of water and begin processing currant leaves;
- Mustard... 10 g of mustard powder is added to 1 liter of water. The infusion is left for a day. Before treating the shrub, it is filtered;
- Ash... 300 g of wood ash is poured into 2 liters of water. The container is placed on the stove and boiled for 20 minutes. When the product cools down, it is filtered and the currant is treated.
Agrotechnical measures
Agrotechnical techniques help to increase the effectiveness of treatment. If red leaves are found on the currants, then it is necessary to revise the care scheme. Be sure to remove the affected branches, weed weeds and throw out the fallen leaves. Then they examine the bush, cut off dry and broken shoots. The branches are cleared of lichen.
In the course of treatment, watering and feeding are normalized. Currants prefer moderately moist soil. Nitrogen fertilizers and manure are applied in minimal quantities. Particular attention is paid to feeding the bush with potash and phosphorus compounds. Such substances increase the immunity of plants and make the treatment more effective.
Causes and treatment of white spots on currant leaves
White spots on black currants cause powdery mildew and septoria disease. The lesion spreads in high humidity and in dense plantings. The first signs appear on young shoots and leaves as a white bloom. It gradually turns brown.Black currants are more likely to suffer from these diseases.
Powdery mildew and septoria reduce the yield of currants by 50% or more. With a strong infection, the growth of shoots stops, and the leaves fall off prematurely. If you do not start treatment, then after 2 - 3 years the bush will die.
White spots on black currant branches can be caused by lichen. To combat it, they carry out sanitization. In case of serious damage, the shoots are completely removed. The lichen is cleaned by hand using a hard washcloth or brush. The barrel is treated with a solution of soap and ash.
For the treatment of bushes, chemical or biological preparations are chosen. The first group includes Bordeaux liquid, Topaz, Abiga-Peak, copper oxychloride. From biological preparations, Fitosporin, Gamair, Alirin are chosen. Spraying frequency - no more than once every 10 - 14 days, depending on the toxicity of the drug.
Preventive actions
So that burgundy spots do not appear on the leaves of the currant, agricultural technology is observed in the garden. In autumn, the soil is cleared of fallen leaves. Pest larvae and fungal spores overwinter in them. Then they dig up the soil under the bushes.
For planting, choose varieties that are resistant to fungal diseases and pests. Black currant Zabava, Karachinskaya, Lazy, Gulliver, Otradnaya, Minusinskaya, Pygmy have high immunity. From varieties with white and red berries, choose the variety Vika, Ogni Ural, Gazelle, Viksne, Marmeladnitsa.
Often, fungal spores and pest larvae enter areas with planting material. Therefore, currant seedlings are taken from trusted suppliers. For disinfection, use a solution of the drug Fitosporin.
Currants are pruned annually to avoid thickening. Choose 5 - 7 strong shoots, the rest are cut at the root. Plants with a strong odor are planted nearby, which will scare away pests. This includes onions, garlic, chamomile, marigolds.
A good prevention is the regular spraying of the bushes. To avoid the appearance of red spots on the leaves, currants are sprayed in spring and autumn. Use chemical or folk remedies.
For the prevention of red spots on currants, the following drugs are suitable:
- Preparation 30 Plus. Provides protection of currants from wintering pests. For processing, choose the period after leaf fall or early spring. For 10 l of water add 500 ml of the suspension. Processing is carried out when the air temperature warms up to +4 ° C. Solution consumption per bush is 2 liters.
- Nitrafen... The drug destroys aphid larvae overwintering in the ground. For processing, a solution is prepared containing 300 g of the substance in a large bucket of water.
Conclusion
There are different ways to treat brown spots on currant leaves. First, the cause of the defeat is determined. Then a suitable method of treatment is selected. Be sure to take into account the season and the stage of currant vegetation.
