Content
Black currants are often planted in summer cottages or garden plots. This shrub is known for its unpretentiousness and stable fruiting. Currants can tolerate low temperatures and short periods of drought. One of the problems when growing is yellowing of the leaves. When black currants turn yellow or react to growing conditions by dropping leaves, 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 do currant leaves turn yellow?
Currant leaves may turn yellow in spring, autumn or summer. Each case can be caused by different reasons. In addition, black currants turn yellow due to the appearance of several factors simultaneously.
The main task of gardeners is to find the reasons why yellow spots appear on currant leaves. Agricultural technicians and experienced gardeners identify 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, a watering schedule is established, and shortcomings 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 causing its leaf blades to turn yellow.
When caring, adhere to the basic rules for planting and caring for blackcurrant seedlings:
- The area where the crop grows must be flat and well lit. The exception is landing in 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, leave about 1.5 - 2 m between seedlings. A smaller distance can lead to a weakening of the root system due to the inability to grow sufficiently in breadth under the top layer of soil. Choosing a dark area, under the crowns of tall deciduous trees, leads to withering of the currant leaf blades, weakening of the emerging shoots, and shrinking of the fruits. Blackcurrant is a sun-loving crop. If, during its development, the plantings around the plot were changed or a building was built to block the sun, 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 may be neglect of watering rules. Black currant responds by yellowing leaves to insufficient moisture or excessive stagnation of moisture. During the flowering and fruiting period, black currants are watered 2 times a week. For each adult bush, allocate 1 bucket of warm water.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;
- Fertilizing is an important point that must be observed when caring for blackcurrants. As a rule, the appearance of yellow spots on the leaves in the absence of fertilizers indicates a lack of nitrogen. This element is responsible for the growth of green mass, the structure of leaf blades, and their rich 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, tree trunk care. Many owners do not attach importance to cleaning the areas around the trunk. At the same time, they follow the rules of watering and fertilizing, spraying the plants, pruning and treating them. Lack of mulching can lead to active loss of moisture during dry periods of summer or the spread of weeds around the trunks, which prevents the root system from receiving enough nutrients from the soil. Insect pests often breed on weeds, which can spread to currants and ruin the harvest.
Adverse weather conditions
The leaves turn yellow due to high air temperatures 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, the leaf blades turn yellow at the edges;
- During frost, yellowing affects only the tips.
Diseases
Many blackcurrant diseases, in which its leaves turn yellow, can be caused by care errors. Diseases overtake a culture for other reasons. Selectively bred varieties are maximally protected from anthracnose, a common currant disease. However, this disease still remains the most dangerous for blackcurrant bushes. In addition, blackcurrants often develop powdery mildew, and they can also suffer from blight, rust, or spotting. In these cases, the currant leaves become 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 blades, then the yellow spots actively turn brown, and the damaged areas of blackcurrant leaves become completely discolored. After this, 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 the concomitant factor of the appearance of spider mites. He is considered a carrier of the virus. At an early stage, it is quite difficult to detect terry. When severe symptoms appear, it is rarely possible to save the culture. The main signs by which terry can be diagnosed:
- the inflorescences acquire a purple hue and a terry structure;
- the leaves on the black currant turn yellow and stretch out;
- berries are prone to shrinking and falling off.
Spheroteka
A dangerous fungal disease, which is characterized by the appearance of a white coating 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. If a spheroteca is detected, black currants are treated with special substances.
Rust
A fungal virus that infects leaf blades. The leaves begin to turn yellow, and orange pads may simultaneously develop on their undersides. White dots appear on the formed berries. The fruits are prohibited from being collected or eaten. By the time the crop is supposed to produce a harvest, the leaves turn completely yellow and fly off, leaving bare shoots. In this case, shoot formation completely stops.
Pests
Insects attack black currants in the spring or after summer flowering. If blackcurrant leaves begin to turn yellow in May, then the reason should be sought on the inner surface of the leaf blades. Insects most often accumulate from below. In this way, they are protected from the scorching rays of the sun and are in close proximity to the leaf veins through which cell sap flows, which is food for most pests.
Gall aphid
One of the varieties of the extensive 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 is plantings of sage, oregano, mint or lavender near the bushes.These plants are often attacked by gall aphids, begin to turn yellow, and then the parasites spread to neighboring crops.
Externally, it is a small insect with an oval body. The color of aphids is pale green, so gall aphids are not easy to notice on the green surface of leaves. The provoking factor for the appearance of gall aphids is often a dry, hot summer. The individual attaches to the lower part of currant leaves. The upper part of the plates begins to gradually turn yellow, then acquires a brown tint. This occurs because aphids suck cell sap from the plant, damaging all layers of tissue. After feeding, a colony of gall aphids can leave the crop together, spreading to neighboring shrubs. By this point, the currant bushes will be weakened, the leaves will continue to change color and structure. The processes can lead to unripe fruits. To combat aphids, stage-by-stage treatments are carried out, thanks to which it is possible to get rid of adult individuals and remaining clutches.
Spider mite
The appearance of an insect is one of the reasons that black currants begin to turn yellow and dry out. Mites feed on cell sap, depriving the bushes of vitality, and also entangle the shoots with a sticky white web, which impedes development. The leaves on the blackcurrant, covered with cobwebs, gradually turn yellow. You can get rid of the insect after several step-by-step treatments.
Currant glass
This insect can hide on black currants for quite a long time. When glass leaves appear, the leaves of the bush begin to turn yellow from the point of attachment to the center, then they dry out and become a habitat for butterfly larvae. The insect lays up to 100 eggs daily; the larvae are located inside the stem.When spreading glass, gardeners advise getting rid of the affected parts of the currant bush and carefully treating the uninfected part.
What to do if currant leaves turn yellow
When the blackcurrant bush begins to wilt, the leaves become covered with yellow veins or dots, gardeners recommend eliminating the provoking factors by changing the approach to caring for the plant. Treating bushes that have begun to turn yellow with special means to cure and get rid of pests helps a lot.
Chemical biological agents
When currants turn yellow, a variety of means are used. The appearance of fungal diseases, as well as the spread of insects, which peaks in the spring, require a different approach. Blackcurrant treatments with chemical or biological agents are carried out in spring and summer.
Preventive
This is a concentrated oil emulsion that consists of an insecticide. This 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 bud swelling. The mechanism of action of the chemical is based on its penetration into the plant and distribution through the tissues. Prophylactic protects the root system, emerging shoots, leaf blades and flowers from pests. For treatment use 1 bottle of Prophylactic with a volume of 500 ml. This dose is dissolved in 10 liters of water and the bush is sprayed using a special garden sprayer.
Kleschevit, Aktofit
They represent the means used to treat black currants during the green leaf phase. This means that treatments are carried out after the leaves appear.Shoots and leaf plates are sprayed. Kleshevit is classified as acaricide, a chemical preparation designed to control and prevent ticks that can infest blackcurrant bushes. In addition, these drugs are suitable for eliminating the symptoms of powdery mildew. Using a sprayer in the spring, small yellow spots on currant leaves are specifically sprayed.
Spark
Chemical insecticides such as Iskra and Iskra-M help protect currants from pests, subject to timely treatment. The period of time between the formation and growth of green foliage is used. Some types of Iskra preparations work well at air temperatures from +25 °C, some analogues require use at temperatures from +18 to +25 °C. Chemical preparations of this group are produced based on the active substance - malathion. The disadvantage of these products is that they are ineffective against pest nests.
Oksikhom
It is a broad-spectrum biological preparation that:
- effective as a systemic contact fungicide;
- able to protect plants from diseases and pests;
- helps cope with spotting, anthracnose, late blight;
- gets rid of ticks and caterpillars.
The drug is used to treat the crop when the first signs of disease or pests appear. The branches are sprayed, and windless days are selected. Spray the product with the condition that residues do not flow into the ground. Oxychome reaches its maximum effect on the third day after treatment, the effect lasts about 14 days.
Traditional methods
No less effective are options for mixtures prepared independently.If blackcurrant leaves turn yellow, experienced gardeners recommend treating them with solutions of onion, garlic, tar soap, and tobacco leaves.
Onion infusion
To prepare the mixture, take onion peels and infuse them in warm water for 15 hours. Then filter the infusion. The resulting liquid is sprayed onto the bushes and dry, windless days are chosen. The influence of onion infusions is due to the presence of phytoncides in onions. They have antiparasitic effects, destroying spider mites and aphids.
Soap solutions
Products based on household or tar soap shavings are widely known. To prepare them, pour boiling water over the shavings and leave for about 10 hours. Then dilute with water 1:1. The resulting solution is sprayed onto the bushes. The products help get rid of most insects and destroy their egg laying.
Tobacco solutions
In spring, black currants are treated with an infusion of tobacco leaves. For effectiveness, add shavings of laundry soap to the solution. Tobacco dust obtained after processing dry leaves is used to dust leaf blades when the first signs of disease or the presence of pests are detected.
Preventive actions
To prevent blackcurrant leaves from starting to turn yellow in early spring or summer after fruit formation, gardeners recommend carrying out a number of preventive measures that will help avoid problems.
Timely pruning of blackcurrant bushes is important when carrying out preventive measures. This method solves several problems simultaneously:
- forms a blackcurrant bush;
- eliminates the possibility of fungus appearing on damaged, diseased branches that must be removed;
- helps prevent thickening of plantings, which often leads to the appearance of insect pests.
Sanitary pruning is carried out in early spring, after the plants emerge from wintering, and also in late autumn, in preparation for further covering of the bushes. Summer pruning is corrective in nature.
A small tree trunk circle is formed around the blackcurrant bushes. This helps to properly mulch the soil around the trunk, as well as adjust the watering technique. Gartering bushes is considered one of the important preventive measures.
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, which become heavier after the berries appear, are placed on the rope.
A good preventive measure against situations where the blackcurrant bush turns yellow is to warm the plant with boiling water in early spring. This method helps eliminate fungal residues and insect particles that froze in the winter but remained on the branches. In addition, boiling water activates the flow of cell sap along the trunk and awakens the plants.
Conclusion
When black currants turn yellow, it becomes clear that a disease is developing on the bush or insect pests have appeared. The main task of gardeners is to detect in time the cause of yellowing of leaves and begin a systematic fight against it. Timely treatment with the necessary means helps to cope with the problems that arise.
