You can successfully fight currant diseases in the garden if you learn to distinguish their signs, otherwise all your efforts will be in vain and the harvest will be lost. For correct diagnosis, you need to know the main symptoms of the most common diseases.
Sometimes on currant leaves and berries you can observe a whole “bouquet” of spots of different colors and shapes. Which of these are indicators that the plant is lacking nutrients, and which are a sign of a serious disease? Is it possible to recognize the disease at an early stage and treat it? Let's find out.
Circular spots on both sides of the leaf surface
If you notice dark brown spots on currant leaves that gradually merge, and the leaves turn yellow and fall off prematurely, this is anthracnose ( Pseudopeziza Ribis Kleb.).
The infection can appear at any time during the growing season. The main damage from it is the abundant fall of leaves, which can begin as early as the end of July. This will lead to loss of harvest next year. Spots can also appear on young shoots, leaf petioles, stems and berries.
Measures to combat anthracnose:
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conclusions
- The development of rust fungus spores directly depends on the climatic conditions of the region.
- Taking preventive measures will help protect currant bushes from pests.
- Loss of currant yield when damaged by goblet rust, as with septoria, is reduced by 50%.
- Fungal spores are carried by the wind, so large areas of berry plantations can become infected in a matter of days.
- Infected berries are poisonous to humans.
- Rust prefers wet weather; it practically does not develop in dry weather.
- In the absence of timely treatment, the harvest will not be able to be harvested, and the bush itself may not survive the winter.
Orange growths on the underside of currant leaves
If carrot-colored pads appear on the underside of currant leaves, filled with a mass of spores in the form of columns of bristles, and on top of the leaves, opposite these formations, red spots have formed, this indicates columnar rust (Cronartium ribicola Ribes). Later, all the leaves on the back side are almost completely covered with an orange “brush” of spores and begin to fall off prematurely, and the shoots dry out and look underdeveloped.
Measures to combat columnar rust:
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Cause of Columnar Rust
The main cause of columnar rust is a fungal spore, the intermediate host of which is sedge.
If this herb grows near a currant bush, then in the spring it will be infected.
Another reason for the spread of spores is considered to be trees such as pine and cedar. And given that currants are very susceptible to fungal pathogens, there is a risk of infection. In this case, it is better to choose such resistant species as the black variety Selechinskaya currant or Primorsky Champion, Eighth Denisova and Chulkovskaya.
Yellow-brown spots on currant leaves
If you notice small brown tubercles surrounded by a yellow border on the upper side of currant leaves, it means that the currant has leaf rust ( Puccinia ribesii caricis). Over time, yellow and red columns appear in place of the pads. Gradually the entire sheet becomes covered with fluffy rust.
Measures to combat leaf rust:
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Measures to prevent the spread of fungus
Preventive measures aimed at combating rust on the currant bush should be carried out at the beginning of the spring period, before the buds have yet appeared. As a preventative measure, the soil under the bush should be fed. To do this, it is better to use phosphorus-potassium fertilizer. As soon as the leaves begin to bloom, they, along with the branches, need to be sprayed with Bordeaux water.
Under no circumstances should currants be planted near coniferous and pine trees. As soon as autumn arrives, currant branches are treated with a two percent Karbofos solution.
Brown or brown spots on currant leaves
If on the leaves or shoots of currants or gooseberries you find small, round, pale grayish spots with a dark brown border, and on them there are black, randomly scattered dots (pycnidia), you should know that this is ascochyta blight ( Ascochyta). Over time, the affected areas of the leaves dry out, crack and fall out.
Measures to combat ascochyta blight:
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Soil care: what to do?
Soil care plays an important role in growing currants. If all necessary measures are taken, the plant will be resistant to pests and diseases.
Main measures for soil care:
- weeding;
- loosening;
- mulching;
- application of fertilizers.
If all activities are carried out in accordance with the agricultural techniques for cultivating black currants, the risk of contracting diseases is reduced.
White coating on currant leaves
If a white powdery coating appears on currant leaves, which over time becomes rusty in color, you should know that this is powdery mildew ( Erysiphaceae). The disease can appear throughout the growing season. Often the edges of the leaves turn brown and black. Severe infection slows down shoot growth and adversely affects next year's yield.
Measures to combat powdery mildew:
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How to treat the bush?
When choosing chemicals to treat brown spots on the leaves of a currant bush, you need to be extremely careful. Because the shrub is a fruit-bearing shrub, pesticides and other harsh chemicals can be hazardous to humans.
All drugs that protect the bush from harmful insects or infections are divided into groups. Each group is characterized by the main active substance and the method of influencing the problem.
If the leaves are swollen
If the leaves of the bush turn red and swell, then it has been attacked by harmful insects, namely aphids. You need to choose the drug wisely, based on the type of impact of the chemical on the life support systems of pests:
- Respiratory. Affects the respiratory organs of insects.
- System. They penetrate the plant tissues of the bush, eating which the insects die.
- Contact. Pests die only in direct contact with the drug.
- Pyrethroid. They are also called intestinal, since the pests die by eating the treated parts of the bush.
To combat harmful insects, you should use specialized preparations - insecticides. They affect both adults and larvae. Depending on the type of action of the drug, you need to spray the bush with a spray bottle or water it at the root.
Popular drugs:
- Fitoverm. Refers to a mixed type of drug (contact-intestinal). The active substance of the chemical is aversectin. Works in hot weather, toxicity decreases at temperatures of +21 °C and above, does not mix with other products;
- Biotlin. Contact-intestinal solution, the active ingredient of which is imidacloprid. To treat shrubs against aphids, you need to dilute 3 g of the substance in 10 liters of clean water. For each bush you need to pour 1.3-1.5 liters of the prepared solution. Helps destroy insects even in hard-to-reach areas, as well as protect the plant from the spread of new colonies of parasites;
- Agravertine. Bio-based insecticide. The active ingredient is avertin. It does not accumulate in plant tissues or in the soil, is not dangerous for beneficial insects, and can be used many times, since it is not addictive to pests. Do not mix with other insecticides; it does not work well at temperatures of +19 degrees and above.
Turn red and curl
Reddened, dried and curled leaves are a symptom of anthracnose. The fungus most often affects shrubs in July and August.
How to fight:
- The soil and shrubs should be treated with a 1% solution of copper sulfate. This must be done before the leaves appear.
- Before the flowers form, you need to spray the bush with Topsin-M.
- During the formation of ovaries, you need to feed the bush with wood ash.
- To strengthen the plant’s immune system, it is necessary to apply complex fertilizers with nitrogen and boric acid.
- Immediately after the harvest is harvested, you need to treat the bushes with Bordeaux mixture (a mixture of lime and copper sulfate).
- All fallen leaves must be burned to prevent fungal spores from spreading to healthy bushes during the winter.
- In the autumn, immediately after digging the soil, you need to treat the bush with Nitrophen.
Small leaves on currants
If you notice that the currant leaves have become small and dark green, and consist of 3 lobes, this is terry leaf, or reversion (Ribes virus) of the currant. The veins of the leaves become coarser, and sometimes chlorosis appears on young leaves, which later disappears. The calyx, corolla, and stamens of the flower look like purple petals. In this case, the berries form ugly or do not set at all, the bushes become abnormally thick with signs of growth (like witches' panicles).
Measures to combat terry:
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Methods for preventing the disease
Methods for preventing the disease can be divided into:
- mechanical;
- chemical;
Mechanical control involves treating the bush with hot water. This method will eliminate pests and increase the plant’s resistance to various diseases.
After this, all dry branches should be cut off. If a large, thick branch is cut, then the cut site is smeared with garden varnish. All removed branches and leaves are destroyed. This measure helps protect the shrub from fungal infection.
The chemical method consists of treating the bush with prophylactic drugs. In March, it will be useful to spray the bush and the soil under it with Nitrophen or Fundazol. They will help protect against the development of rust and defeat currant bush disease.
Yellow spots on currant leaves
If you find round, vague, pale yellow spots with a light green center on the leaves of a red currant, located between large veins, and see that the leaf blade is growing unevenly, it means the plant is affected by mosaic ( Mosaica ) . Over time, the spots merge, the leaf turns completely yellow, the affected tissue between the veins turns white and dries out.
Measures to combat mosaic:
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White spots with a brown border
If the leaves are covered with small angular spots up to 2-3 mm in diameter, first brown, then white with a brown border - this indicates septoria, or white spot (Septoria), of currant leaves.
Measures to combat septoria:
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As you can see, your concern about the variegated color of currant leaves is most likely justified. The list of currant diseases includes several dozen varieties, so it is especially important to identify signs of infection in the early stages in order to begin treatment in a timely manner.
Ways to fight
There are enough anti-rust techniques available to get rid of the disease. But it is necessary to know exactly which type of rust the gardener is faced with.
This helps you choose the right fighting technique. For effectiveness, it is worth considering the stage of development of the disease.
Effective preparations and rules for processing shrubs
Chemicals have an active effect on pathogenic microorganisms. If you choose the right substance, rust will be eliminated in a short time.
Control measures include additional preparation of currant bushes. In other words, you cannot start spraying or applying the drug without:
- Trimming infected parts, removing diseased foliage.
- Complete elimination of affected parts. To do this, they are burned. The procedure will ensure the cleanliness of the area and the absence of relapse.
- Soil drainage. The event is aimed at removing moisture.
Having completed three steps, we begin treatment with substances purchased in advance at the store.
Cuproxat
The main active ingredient of the drug was copper. The element perfectly resists pathogenic fungi.
Copper acts quickly due to the penetration of spores. Naturally, the organism dies twice as fast and stops reproducing and spreading.
The best results are obtained if spraying is carried out taking into account weather conditions: in calm, cloudy weather, but without precipitation.
You can also carry out the work early in the morning after the dew has dried or late in the evening. The effect of Kuproxat will be obvious not only on currants, but also on other neighboring crops.
