Content
Black currants are often planted in summer cottages or backyards. This shrub is known for its unpretentiousness and stable fruiting. Currants can tolerate low temperatures and small periods of drought. One of the problems with growing is the yellowing of the leaves. When black currant turns yellow or reacts to growing conditions with leaf fall, it is important to find the causes of such problems in order to find ways to deal with the problem in a timely manner.
Why currant leaves turn yellow
Currant leaves can turn yellow in spring, autumn or summer. Each of the cases can be triggered by different reasons. In addition, black currants turn yellow due to the appearance of several factors at the same time.
The main task of gardeners is to find the reasons why yellow spots appear on currant leaves. Agricultural technicians and experienced gardeners highlight several main factors why leaves turn yellow. Each of them needs to be considered in more detail.
Improper care
After planting the seedlings, an equally important period of caring for the growing bush begins. During this time, an irrigation schedule is established, and deficiencies are also discovered when preparing a planting site or when choosing a site for planting. If violations are made to one of the points, then the currant may react by turning its leaf plates yellow.
When leaving, they adhere to the basic rules for planting and caring for black currant seedlings:
- The area where the culture grows should be flat, well lit. An exception is landing on the path of through winds. The best option for black currants is considered to be places along fences and hedges with the necessary indentation for growth. When planting, about 1.5 - 2 m are left between the seedlings. A smaller distance can lead to a weakening of the root system due to the impossibility of expanding sufficiently in breadth under the top layer of soil. The choice of a darkened area, under the crowns of tall deciduous trees, leads to wilting of currant leaf plates, weakening of emerging shoots, and shrinking of fruits. Blackcurrant is a sun-loving crop. If, during its development, on the personal plot there was a change in plantings around or a building covering the sun was built, then it will not be possible to avoid the fact that the leaves of the bush will turn yellow;
- One of the violations of care can be neglect of watering rules. Black currant responds by yellowing the leaves to insufficient moisture or excessive moisture stagnation. During the flowering and fruiting period, black currants are watered 2 times a week. For each adult bush, 1 bucket of warm water is allocated. Planting black currants in lowlands, where possible stagnation of water leads to rotting of the root system, provokes a change in the color and structure of the leaves. As a result, the leaves turn yellow;
- Top dressing is an important point that must be observed when caring for black currants.As a rule, the appearance of yellow spots on the leaves in the absence of fertilization indicates a lack of nitrogen. This element is responsible for the growth of green mass, the structure of the leaf plates, their saturated color. During the fruiting period, currant leaves begin to turn yellow if the fruit does not have enough potassium and phosphorus. Fruit formation begins to take all the strength from the leaf plates, shoots and roots: thus, the fruits remain large, and the leaves begin to turn yellow;
- Loosening, mulching, caring for the trunk circle. Many owners do not attach importance to cleaning the areas around the trunk. At the same time, they observe the rules of watering and feeding, spray the plants, cut and process them. Lack of mulching can lead to active moisture loss during dry periods of summer or the spread of weeds around the trunks, which prevents the root system from getting enough nutrients from the soil. Weeds often breed insect pests that can spread to currants and spoil the crop.
Unfavorable weather conditions
The leaves turn yellow due to the high air temperature in summer in the absence of sufficient watering. In addition, early frosts in the fall can provoke yellowing. This type of yellowing is determined by the degree of localization:
- during drought, leaf plates turn yellow at the edges;
- in case of frost, yellowing affects only the tips.
Diseases
Many diseases of black currant, in which its leaves turn yellow, can be triggered by care errors. Diseases overtake culture for other reasons. The varieties bred by selection are maximally protected from the anthracnose disease common for currants. Nevertheless, this disease is still the most dangerous for blackcurrant bushes. In addition, powdery mildew often develops on black currants, and they can also be affected by terry, rust or mottling. In these cases, the leaves of the currant are covered with yellow dots.
Anthracnose
The most common fungal disease among different varieties of black currant. It begins with the appearance of yellow spots on the leaf plates, then the yellow spots actively turn brown, and the damaged areas of black currant leaves completely discolor. After that, anthracnose gradually affects the petioles, as a result of which the leaves fall off or, remaining on the shoots, begin to turn yellow and rot.
Terry
This disease is associated with a concomitant factor in the appearance of a spider mite. He is considered a carrier of the virus. Terry is difficult to detect early on. With the onset of severe symptoms, it is rarely possible to save the culture. The main signs by which you can diagnose terry:
- inflorescences acquire a purple hue and a terry structure;
- leaves on black currant turn yellow, stretch;
- berries are prone to crumbling and falling off.
Spheroteka
A dangerous fungal disease, which is characterized by the appearance of white bloom on different parts of the plant. The affected areas of black currant leaves begin to gradually turn yellow, then dry out and curl. The formed fruits do not have time to ripen. In addition, a concomitant factor may be the appearance of yellow dots on currant leaves, which darken over time and acquire a black tint. When a spheroteka is found, black currants are treated with special substances.
Rust
Fungal virus that infects leaf plates. The leaves begin to turn yellow, and orange pads can develop on the underside at the same time. White dots appear on the formed berries.It is forbidden to pick and eat fruits. By the time the crop is due to harvest, the leaves are completely yellow and fly around, leaving bare shoots. In this case, shoot formation completely stops.
Pests
Insects attack black currants in spring or after summer flowering. If the leaves of black currant begin to turn yellow in May, then the cause should be sought on the inner surface of the leaf plates. Insects most often congregate from below. In this way, they are protected from the scorching rays of the sun and are in close proximity to the veins of the leaf, through which the cell sap flows, which is the food for most pests.
Gall aphid
One of the varieties of the vast family of aphids. Most often, gall aphids can be found on red currants, but black currant bushes also attract the parasite. One of the provoking factors for the spread of gall aphids on currant bushes are plantings of sage, oregano, mint or lavender near the bushes. These plants are often invaded by gall aphids, begin to turn yellow, and then the parasites spread to neighboring crops.
Outwardly, it is a small insect with an oval body shape. The color of the aphid is pale green, so the gall aphid is not easy to see on the green leaf surface. The provoking factor for the appearance of gall aphids is often a dry hot summer. The specimen is attached to the lower part of the currant leaves. The upper part of the plates begins to gradually turn yellow, then acquires a brown tint. This is due to the fact that aphids suck the cell sap from the plant, damaging all layers of tissue. After feeding, the colony of gall aphids can amicably leave the culture, spreading to neighboring shrubs. By this time, the currant bushes will be weakened, the leaves will continue to change their shade and structure. The processes can lead to unripe fruit. To combat aphids, stage-by-stage treatments are carried out, thanks to which it is possible to get rid of adults and the remaining clutches.
Spider mite
The appearance of an insect is one of the reasons that black currants begin to turn yellow and dry out. Ticks feed on cell sap, depriving the bushes of vitality, and also entangle the shoots with a sticky white cobweb that prevents development. Leaves on black currants, covered with cobwebs, gradually turn yellow. You can get rid of an insect after several step-by-step treatments.
Currant glass
This insect is able to hide on black currant for a long time. The leaves of the shrub, when the glass pan appears, begin to turn yellow from the point of attachment to the center, then they dry up and become the habitat of the butterfly larvae. The insect lays up to 100 eggs daily, the larvae are located inside the stem. When spreading the glass, gardeners are advised to get rid of the affected parts of the currant bush and carefully handle the uninfected part.
What to do if currant leaves turn yellow
When the black currant shrub begins to wilt, the leaves become covered with yellow streaks or dots, gardeners recommend eliminating provoking factors by changing the approach to plant care. It helps well to treat bushes that have begun to turn yellow with special means for curing and getting rid of pests.
Chemical biological agents
When the currants turn yellow, a variety of remedies are used. The emergence of fungal diseases, as well as the spread of insects, which peak in the spring, require a different approach. Blackcurrant treatments with chemical or biological agents are carried out in spring and summer.
Prophylactin
It is a concentrated oil emulsion that consists of an insecticide. It is a chemical that is specifically designed to kill pests. It belongs to one of the types of disinfection and is used before the period of swelling of the kidneys.The mechanism of action of a chemical agent is based on its penetration into the plant and spread through tissues. Prophylactin protects the root system, the resulting shoots, leaf plates and flowers from the appearance of pests. For processing, use 1 bottle of Prophylactin with a volume of 500 ml. This dose is dissolved in 10 liters of water and the shrub is sprayed with a special garden spray.
Kleschevit, Aktofit
They represent the means with which black currants are treated during the green leaf phase. This means that treatments are carried out after the appearance of the leaves. Shoots, leaf plates are sprayed. Tickschevite belongs to the type of acaricides, chemicals designed to combat and prevent ticks that can populate black currant bushes. They are also suitable for treating powdery mildew symptoms. With the help of a sprayer, yellow small spots on currant leaves are purposefully sprayed in spring.
Spark
Chemical preparations-insecticides such as Iskra and Iskra-M help to protect currants from pests, provided that they are treated in a timely manner. Use the time period between the formation and growth of green foliage. Some varieties of Iskra preparations work well at air temperatures from +25 ° C, some analogues imply use at temperatures from +18 to +25 ° C. Chemicals of this group are produced on the basis of the active substance - malathion. The disadvantage of these funds lies in the fact that they are ineffective against the clutches of pests.
Oxyhom
It is a biological product with a wide spectrum of action, which:
- effective as a systemic contact fungicide;
- able to protect plants from diseases and pests;
- helps to cope with spotting, anthracnose, late blight;
- eliminates ticks and caterpillars.
The drug is treated with the culture when the first signs of disease or pests are detected. Branches are sprayed, while calm days are chosen. Spray the agent with the condition of avoiding the flow of residues into the soil. Oxychom reaches its maximum effect on the third day after treatment, the effect lasts about 14 days.
Traditional methods
No less effective are the options for mixtures prepared by yourself. If the leaves turn yellow on black currant, experienced gardeners recommend treating them with solutions of onions, garlic, tar soap, tobacco leaves.
Onion infusion
To prepare the mixture, take onion husks, insist in warm water for 15 hours. Then filter the infusion. The resulting liquid is sprayed on the bushes, dry, windless days are chosen. The influence of onion infusions is due to the presence of phytoncides in the onion. They have antiparasitic effects, destroying spider mites and aphids.
Soap solutions
Means based on shavings of laundry or tar soap are widely known. For their preparation, the shavings are poured with boiling water, insisted for about 10 hours. Then they are diluted with water 1: 1. The resulting solution is sprayed with bushes. The products help get rid of most insects and destroy their clutches of eggs.
Tobacco solutions
In the spring, black currants are treated with infusion of tobacco leaves. For efficiency, shavings of laundry soap are added to the solution. Tobacco dust obtained after processing dry leaves is used to dust the leaf plates when the first signs of a disease or pests are detected.
Preventive actions
To prevent black currant leaves from turning yellow in early spring or summer after the formation of fruits, gardeners recommend a number of preventive measures to help avoid problems.
Timely pruning of black currant bushes is important in carrying out preventive measures. This method solves several tasks at the same time:
- forms a black currant bush;
- eliminates the possibility of the appearance of fungus on damaged diseased branches that must be removed;
- helps prevent thickening of plantings, which often lead to the appearance of insect pests.
Sanitary pruning is carried out in early spring, after the plants leave wintering, as well as in late autumn, in preparation for further shelter of the bushes. Summer pruning is corrective.
A small trunk circle is formed around the black currant bushes. This helps to properly mulch the soil around the trunk, as well as to adjust the irrigation technique. One of the important preventive measures is considered to be the garter of the bushes.
This applies to varieties with spreading lower branches to prevent them from falling to the ground. Supports are installed around the bushes and tied with synthetic nylon ropes in a circle. The lower branches are laid on the rope, which become heavy after the appearance of the berries.
A good preventive measure against situations when the black currant shrub turns yellow is to warm the plant with boiling water in early spring. This method helps to eliminate the remains of the fungus, insect particles that were frozen in winter, but remained on the branches. In addition, boiling water activates the flow of cell sap along the stem, awakens the plants.
Conclusion
When the black currant turns yellow, it becomes clear that a disease is developing on the bush or that pests have appeared. The main task of gardeners is to find the cause of the yellowing of the leaves in time, to start a systematic fight against it. Timely processing with the necessary tools helps to cope with the problems that have arisen.
