Currant diseases and their treatment
Currant is a berry with a bright taste. She likes most people. But in order to get the crop that is optimal in terms of volume and quality, you will have to deal with a number of unpleasant factors.
Diseases
There are a number of currant diseases in the description of which red spots are mentioned. This kind of negative manifestation is especially often associated with an infection or with an attack of pests from April to August inclusive. Less commonly, this problem occurs in the fall. Most likely, the appearance of such a problem with the defeat of anthracnose. It equally often appears on black, red and white currants.
The harm of anthracnose is not limited to the deterioration of the external appearance of plants. Shoots begin to grow worse, yields are reduced. And even those fruits that still manage to be harvested will turn out to be less palatable. The first phase of the lesion is sometimes expressed instead of red spots on the foliage in the appearance of plaque in the form of shiny tubercles. Gradually, the protrusions merge and turn brown, while the foliage turns yellow and dries.
If red currants grow on the site, the leaves will fall off pretty quickly. In the black variety, they are able to hang until the end of autumn. But this is not very pleasant, because the mutilated foliage only spoils the view and is unable to fulfill its function. The continuation of the disease leads to a gradual infection of the fruit. The spores of the fungus survive the winter in fallen leaves, so you need to get rid of it stubbornly and without a trace.
The good news is that when the summer is hot and there is little rainfall, the likelihood of getting sick is low. But still it persists. And therefore it is worth carefully, at least once a week, inspecting all the bushes in order to timely notice the lesion.
There are other currant disorders in which it sheds berries. It is worth noting that such a loss of yield is not always associated precisely with pathological processes. When a shrub is planted recently, it may simply not have time to gain the necessary condition. Therefore, the plant loses berries, does not cope well with their retention on the branches. For a similar reason, the problem also occurs on old bushes that have almost outlived their time. For gardeners, this is a kind of warning that allows you to prepare for planting a new currant or for a radical change to another crop.
It is also worth checking for non-pathological conditions such as:
- moisture deficiency;
- wrong site selection (excessive shadow);
- lack of pollination;
- mechanical defects of the shrub;
- pest action.
Berries fall off, however, also due to fungal infections. This problem occurs especially often when currant plantations step over a ten-year milestone. White plaque indicates defeat by powdery mildew. Anthracnose is also capable of destroying the crop in the bud, it is recognized by black dots on the leaves, and in its developed form by brown spots.
It is recommended to always check if the plant is not overloaded with fruits, sometimes it simply adapts to the current situation.
Currant chlorosis invariably turns out to be a formidable adversary for gardeners. The infection is expressed in the fact that in the last days of June or early July, a change in the color of the leaves suddenly begins.Initially, the green color becomes paler (lighter), then an admixture of yellowness appears. Gradually, it grows and ends with a complete yellowing of the foliage, up to a deathly white hue. The leaves are repainted very quickly, each change in tone occurs in a maximum of 10 days, and the end is always the same - early leaf fall.
Due to lack of nutrition, fruits develop insufficiently. And even those berries that can be collected are small in size. Probably problems with laying the crop for next year. In trees affected by chlorosis, first of all, the tops of young shoots dry out.
Moving further, the lesion covers the shoots and passes to the main branches. It is noted that with chlorosis currant lives 2-3 times less than a healthy plant. She suffers much more from freezing in winter. After all, the tissues of the tree accumulate many times less nutritional components than are required to overcome the frosty period. Chlorosis can be expected due to factors contributing to it, such as:
- prolonged drought;
- flooding gardens;
- excessive concentration of lime in the ground;
- long-term absence of organic fertilizers and the depletion of the fertile layer associated with it;
- deficiency or even total exhaustion of easily digestible forms of iron;
- poisoning with various substances.
But suppose there were no floods in the garden, the weather is not dry, there are enough fertilizers and farmers do not abuse pesticides. Nevertheless, the occurrence of chlorosis due to other factors is quite likely. So, it is enough to get poisonous substances with industrial emissions, a high rise in groundwater, or the use of obviously incompatible vaccinations. Another source of the problem is the over-introduction of chicken manure.
The difficulty lies in the fact that it is impossible every time to conduct a comprehensive investigation involving chemists, biologists and experienced agronomists. Even soil analysis, which seems to be an ordinary thing, costs thousands of rubles. For ordinary summer residents, such an amount is unbearable. There is still a way out: train your powers of observation and learn to understand what exactly happened based on visual manifestations. Leaves turning yellow throughout the shoot are the result of soil oxygen deficiency.
Sometimes it is provoked by the farmers themselves. Currant loves water moderately, and they mindlessly water it, bringing it to flooding. But in some cases, the root cause is stubborn cyclones, bringing rain or pouring stormy downpours. There is only one result: almost all the air is forced out of the soil. It is extremely difficult to do something in such an environment, so it remains to count on a more successful next season.
When the weather is good, but no organics have been added for a long time, the likely primary source of chlorosis is the absence of worms or their migration to more favorable areas. These invisible diggers are digging kilometers of tunnels, facilitating the access of oxygen and water. The absence of such passages, together with a limited amount of humus, creates a lot of problems. Quickly "close the issue" will not work. First you have to add organic fertilizer with a margin, then loosen the earth so that it remains scattered to the depth of the fork entry.
For a while, the garden or vegetable garden will have to be kept moist. This is exactly what farmers do when they decide to radically break with an erroneous course of action and make amends to the plantations. If yellowing of the foliage is noticeable on the shoots from bottom to top, the most likely culprit is poor nitrogen nutrition.But the movement of yellowness in the opposite direction immediately reveals a lack of iron. From the yellowed leaves between the veins, experienced farmers will immediately say: the earth has lost its supply of zinc.
A purely infectious nature is such a currant ailment as septoria. Its main foci cover leaves, berries and shoots are much less often affected. Diseased leaves are distinguished by rounded or angular spots up to 0.3 cm in diameter. The initial color of the foci is brown, soon their middle part turns white, while the perimeter is surrounded by a dark brown rim. A very powerful development of the infection leads to the fusion of spots and can even destroy the infected parts of the plant.
The appearance of black dots in the central parts of the foci allows us to speak about the high intensity of the process. Berries and stems are also covered with separate spots of this kind. First of all, you need to look for them at the poles of the fruits and on the stalks. Septoria is provoked by a fungus, so it most actively attacks currants and other plants in hot, wet weather. The threat is especially great in the second part of the summer, it is facilitated by the onset of planting disease with unreasonably high density.
Currant leaves become infected with septoria in the spring. The source of the infection is spores thrown out by structures of the fungus that have matured on already diseased stems and fallen leaves. A characteristic feature of the infection is that the upper shoots suffer less and less frequently. Even with a stubborn struggle, the productivity of bushes is likely to drop by 40, sometimes by 50%.
If we compare septoria with scab, you should immediately point out the insidiousness of the second ailment. It is provoked not only by fungi, but also by actinomycetes, and even bacteria.Under the influence of scab, leaves and underground parts, shoots and berries are affected, the yield decreases sharply. It should be borne in mind that all types of plants affected by scab have a special appearance. The situation in which the disease would have passed from potatoes to apple or berry crops has been excluded. But the similarity of external manifestations, which makes it possible to give a common species name of the disease, still attracts attention.
Sick plants have scaly skin. Both spots and pustules appear on them. It is likely the formation of warts and ulcers. The strong activity of the pathogen leads to drying and falling of foliage, disorganizes the movement of juices in the plant. Both the current and future crops are under threat.
When the scab covers the flowers and buds, they also fall off, previously losing their grace. If you try to save fruits with scab, they easily begin to rot. A convenient entrance for decomposing microorganisms are cracks in the peel. Gardeners who have planted currants should be afraid of scab only under certain meteorological conditions. High humidity is critically important, without which the infection is almost unviable.
In the spring, the fungus begins to act when the snow melts and the air warms up to about 12 degrees. In summer, scab is actively developing if:
- dew falls frequently;
- there is systematically dense fog;
- heavy rains are coming.
It is in the power of farmers to eliminate another risk factor: excessively dense planting. The danger is especially great when the aisles are filled with herbaceous plants, which easily transmit spores from one tree to another. There is a growing danger of scab transfer in gardens whose owners do not bother with species diversity.Infection directly with the currant of the currant bush is quite likely, but it will be harder for the fungus to transfer the bridge from the apple tree to the berry crops, for example.
Another important point is the immune characteristics of the variety, they can vary significantly. If the branches simply dry, it should be blamed primarily on harmful insects. Only when the assumption of their invasion is rejected, it makes sense to look for pathology. For your information: on red, black and white currants, diseases should be treated in approximately the same ways.
Goblet rust is another type of fungal infection. The external manifestation of the disease is the appearance of orange with a red tint of blisters on the leaves.
The transfer of fungal spores occurs due to gusts of wind, but initially they develop on sedge. Goblet rust, like other fungal infections, needs moist weather to thrive. The name of the disease is given by the characteristic change in the color of the foliage. In the advanced phase of the disorder, it may disappear, and soon the same fate befalls the fruits. There is also columnar rust, the primary source of which is coniferous trees; this enemy attacks primarily black currants.
At first, you can only notice small spots of yellow color, appearing in different places on the foliage. From below, these spots correspond to orange pads. Leaf fall noticeably accelerates compared to the norm, the development of shoots slows down. Currant bushes affected by columnar rust survive the winter much worse than healthy ones. Important: regardless of the reason that provokes the degradation of parts of the bush, it must be dealt with immediately.
Drying of shoots is a separate disease that appears more often on red and white currants than on black varieties. The disease is expressed in the rapid death of the branches. Initially, the branches are covered with small orange dots, which are quite difficult to notice. But gradually the affected areas become larger and transform into brown protrusions. Once the spores mature, these projections will turn black.
The defeat of gray rot occurs due to the movement of spores by wind and rain. The source of infection is diseased branches and fruits that have degraded to the state of a mummy. A characteristic defect is brown spots on the foliage. Importantly, gray rot is often accompanied by mold damage and attacks primarily white currants. On this list of dangerous fungal pathologies of the shrub can be completed.
Viral infections are even worse than the fungus, sometimes they end with the complete death of the plant. Getting rid of harmful microorganisms is impossible in principle. Terry, or in other words, reversion, deprives any chance to harvest the fruits. There is no currant disease that would affect it worse. Terry begins to affect already at the flowering stage, so at this moment you need to carefully examine the petals and foliage.
Normally, leaves with five lobes grow on the currant, but if the plant is affected by terry, two lobes disappear. The ends are sharpened and stretched. There are fewer teeth on the edges, and each of them is larger than the usual norm. An unusual darkening of the foliage is noted, the characteristic currant aroma completely disappears. Differences from the norm also appear during flowering - it occurs a few days later than required.
The inflorescences themselves are miserable in appearance and oblong, painted in a dirty pink color, sometimes the green color remains. The formation of berries is excluded, soon the affected inflorescences will dry out. It should be borne in mind that there are currently no ways to deal with terry.
Even when only one branch is sick, you need to get rid of the entire bush. Moreover, the greens have to be burned to prevent the spread of infection.
As for the striated mosaic virus, its distribution is due to:
- defeat of aphids;
- contact with ticks;
- grafting infected cuttings onto initially healthy bushes;
- pruning various plants without changing or disinfecting the tool.
Sick plants differ from the first days of June. The main veins of their foliage acquire a bright yellow color. Like other viral disorders, currant striped mosaic is irreparable. The only way to fight is prevention. When the plant does get sick, it is uprooted as soon as possible and set on fire. At the same place, the next attempt to grow currants is made at least after 5 years.
Alternariosis is a serious fungal infection of the currant, in which its leaves are covered with gray spots with a black tint. The disease covers the stalks and cuttings. Its crushing power hits the foliage, berries, green shoots. By the end of summer, currant bushes are covered with a strong, elastic bloom, it is described as a brown olive film. The causative agent of alternariosis does not destroy red and black currants. However, the development of plants is suppressed, their branches ripen worse, they can even freeze in winter. It is also not worth counting on a normal harvest.
It is also important to know about the signs of cercosporosis, sometimes also called brown spotting.It is characterized by chestnut-colored spots, the outer edge of which is bordered by a light stripe. Gradually, the growth of spots leads to the appearance of a continuous brown layer on the plate.
Phyllostic blotch is seen first on the outside of the leaf. With this disorder, small reddish spots appear. Later they lighten and acquire a dirty brownish tint. In a severe form of the disease, diseased parts of the leaf often fall off, leaving empty holes. Ascochitosis infects black and red currants.
Any fungal spotting leads to:
- the death of foliage;
- unreasonably early leaf fall;
- freezing or drying of young shoots;
- a general deterioration in the resistance of the bush to cold;
- loss of productivity;
- bad taste of harvested berries.
With verticillium wilt, the vascular system suffers primarily. Mycelial strands tend to grow as soon as possible. But as they occupy the root vessels, these canals become impermeable and rot. No matter how much moisture the root gets, no matter how fertile the earth is, the surface part starves and suffers from thirst. Signs are predictable:
- yellow leaves;
- dried berries;
- early death of the bush.
Healing with verticillium wilt is impossible. All that remains for gardeners is to sigh sadly and destroy diseased plantings in the flames of a fire. Plus, it’s better to take care of prevention for the next year.
Another thing is moniliosis, aka fruit rot. Even those ignorant in agronomy and microbiology will be able to recognize such a pathology. A sufficient basis for the diagnosis is the clarification and flabbiness of the berries. Even these weak, puny fruits cannot stay on the branch in full. Some of them fall off and crumble to the ground before the time allotted by nature.
Each such berry must be collected and eliminated, because it is a time bomb.
Prevention
To protect currant bushes from various kinds of ailments, special spraying should be done. In the spring, the Zircon remedy manifests itself best. Re-processing is also allowed, which must be done in the last days of August. An important measure of preventive care for shrubs is autumn spraying. Urea is prepared for it by dissolving it in water in a proportion of 7%.
With such a preparation, it is required to process not only the bushes themselves, but also the ground under them. To further enhance protection, "Zircon" is used again - already in April. In the spring, before the buds swell, but after the end of severe cold weather, currants are poured with boiling water. Its preventive properties will be higher with the addition of soda or potassium permanganate. These reagents do an excellent job with a fungal infection and at the same time with a spider mite.
An important preventive measure is compliance with the principles of crop rotation and acceptable neighborhood. To reduce the threat of infection with viruses (again, they are all incurable), we must fight the invasions of aphids and mites. Careful selection of planting material is of great importance. In case of cold wet weather, shelter sometimes helps. Full drainage of the orchard speeds up the removal of water, and also somewhat reduces the risk of waterlogging during heavy rainfall.
Powdery mildew prevention necessarily implies the optimization of nitrogen fertilization doses applied directly under the bushes. Excessive volume of it leads to an increased risk of disease.If part of the plantings is affected by anthracnose, its further spread can be stopped by carefully cleaning the fallen leaves. It is subject to disposal and is unsuitable as a fertilizer. It is impossible to transplant and graft individual parts of diseased plants.
Agrotechnical prevention of currant diseases includes:
- planting seedlings with root necks set at 30-50 mm and with pruning of shoots (a maximum of 2 or 3 buds should remain above the surface);
- regular watering;
- rational mulching;
- change of bushes that have lived for 7 years to younger plants;
- normal annual pruning;
- digging between rows in autumn;
- treatment of all damage, regardless of their origin, with garden pitch;
- the use of wood ash to supplement under the bushes (this saturates the bush with phosphorus and potassium, while strengthening immunity to powdery mildew).
A strong prophylactic is an infusion of cow dung. 5 kg of it is poured with water to the very edge of the bucket and put in heat for 2-3 days. Next, a couple of liters of the prepared composition are diluted with 10 liters of pure water. You can dilute both in a bucket and in a watering can. But apply only by watering the foliage from a watering can.
A more pleasant option involves the use of dairy products dissolved in water. Among them, low-fat kefir and regular milk are optimal. The proportion of dilution is 10%. Sometimes 5-6 g of pharmacy iodine is also injected here, but this is at the discretion of the farmers. It is undesirable to insist on such a drug, it should be applied immediately. Special microorganisms living in milk and dairy products become a barrier to parasitic fungi.
The preparation of infusion of celandine is also possible using cut branches, flowers of the plant.They fill an ordinary bucket (designed for 10 liters) to the middle. After adding water, wait from 2 to 4 hours. Then you can immediately process the currant bushes. Such a procedure will not protect directly from diseases, but it will destroy aphids and mites that climb into the kidneys. Namely, these organisms are responsible for the spread of many infections.
A good prevention in some cases is the use of an infusion of onion or garlic. 1 fruit is poured into 1 liter of water at room temperature and placed in heat for a week. If the temperature in the room is quite high, you can reduce the exposure time to 5 days. Direct preparation consists in diluting 20 g of the solution in 10 liters of water. Such an infusion is effective not only against fungi and microbes, but also in the fight against aphids, mites.
You can prevent anthracnose by choosing varieties that are resistant to it: Chulkovskaya, Victoria or Generous currant. But even seedlings of these plants are subject to careful selection. Before disembarking, they are dipped for 5-6 minutes in a weak (1%) solution of copper sulfate and washed in clean water. Planting is recommended only where currants have never grown before. It is categorically unacceptable to approach trees and use lowlands.
When currants are treated or solutions are applied for preventive purposes, it is very important that they fall on the entire bush. We must not forget that the lower edge of the sheet also needs protection or help. Goblet rust infestation can be prevented by removing sedge from the site and avoiding planting currants wherever they grow. It is also worth abandoning the idea of \u200b\u200bbreeding this shrub in wetlands. Even if the swampiness is moderately pronounced, it presents favorable conditions for infection.
Prevention of columnar rust in general requires the same approach as the containment of anthracnose. A specific measure is only top dressing with mixtures containing zinc and copper sulphate. It is also worth using potassium nitrate and superphosphate. Ammonium nitrate is undesirable. Of the relatively resistant varieties, agronomists recommend the "Chulkovskaya" berry.
Folk ways
Processing with boiling water in some cases helps to save currants no worse than patented factory products. It is required to water shrubs and the ground around them evenly with hot water. To make the work go more efficiently, it is worth mixing potassium permanganate into boiling water. Immediately after completion of the treatment, pruning is carried out, and the old leaves and old mulch should be removed. The use of Bordeaux liquid is also useful, however, boiling water itself often helps to preserve the health of the bushes, especially if there are no special reasons for alarm.
It should be borne in mind that steep boiling water is not suitable for processing bushes. It is worth waiting for a while and let the water cool down. Before processing, it is recommended to tie the branches together. If the plant has already “come to life”, even only in a small part, it is impossible to water it: you need to try to be in time between the start of warming and the formation of a green bud on the bush. Another option is to use boiling water in the winter, as soon as the leaf fall ends.
Good results can be obtained by treatment with colloidal sulfur. This formulation is used as a suspension at a concentration of 0.5%. Shrubs are processed five times per season. For the first time they make it before flowering, and then the composition is used immediately after it ends. Then they make pauses of 10 and 20 days. The final blow to the infection is applied when the crop is harvested.
Prepare the suspension as follows:
- collect 50 g of sulfur powder;
- diluted in a certain volume of warm water to make a slurry;
- water is added in small portions, achieving a total volume of liquid of 10 liters.
The use of celandine helps to support the treatment with synthetic preparations or even completely replace them. It simultaneously strikes at microorganisms and pests visible to the naked eye. For the preparation of a liquid preparation, 4 kg of fresh crushed shoots or 1 kg of dried green mass are usually used. Such raw materials are poured into 10 liters of water and kept under a lid in a warm room for 36 hours, then filtered. The same infusion helps a lot in protecting gooseberries. Another option involves the use of a powder obtained from dried shoots of celandine: bushes should be powdered with this powder.
Wood ash, along with its main task - the fight against powdery mildew, helps to expel moths and various sawflies from the site. To prepare the mixture, 0.3 kg of ash is dissolved in a bucket of water and infused for 48 hours. The addition of 0.04 kg of laundry soap helps to increase the adhesion of the composition to the foliage. If powdery mildew has appeared, sometimes an infusion of rotten hay also benefits. They are processed 2 or 3 times with a gap of 5-7 days; for wood ash, two treatments are recommended, separated by 10-12 days.
Fighting methods
Currant pathologies should not be taken lightly. The approach to dealing with them varies greatly depending on the current season. It is required to process the plant in the spring as early as possible. Then it is possible to get ahead of the awakening of both the kidneys and aggressive microorganisms and pests that carry them. In some cases, they begin to fight before the snow cover comes off.
The very first step is to closely inspect the plants and remove any dead branches. Along with them, you will have to remove everything that is beaten by frost, ice or snow movements. The longer the delay with such a procedure, the higher the risk of problems.
Currant plantations deserve special attention in autumn. Since the harvest is completely removed, you can use any means you like, without being embarrassed by their particularly harmful effects. But at the same time, of course, we must not forget about our own safety.
Watering currant bushes with boiling water in autumn is a useless exercise, because microorganisms and pests hidden in the kidneys are inaccessible to it.
Before treatment or prophylaxis in the autumn months, pruning is mandatory. It is even easier for plants to experience than in the spring, because seasonal dormancy sets in and stress is reduced. It is recommended to combine "business with pleasure": since the right moment has fallen to make a sanitary pruning, why not form a crown at the same time, do not thin it out. All shoots of the sixth and subsequent years must be removed. You still can’t wait for berries from such parts, but they become a fertile base for infection.
As soon as pruning is completed, the shrub should be sprayed with a solution of karbofos or colloidal sulfur. Their concentration is 2% and 1%, respectively. Such compounds must be applied not only to the bushes themselves, but also to the areas adjacent to them. Only after the end of spraying against the background of dry autumn is watering done before winter. Regardless of the humidity, the circle near the trunk is covered with a fresh layer of organic mulch, taking measures to prevent infected plants and their parts from getting there.
How exactly to treat currants, including during flowering and immediately after it, is determined only by an attentive, thoughtful study of the situation. So, when red spots appear, you should check the version of aphids. If it is correct, along with color blotches, sticky traces will be found. And early shoots and foliage will concentrate the colonies of the aggressor. These two signs (or their absence) allow us to draw an unambiguous conclusion.
The defeat of anthracnose, according to agronomists, is worse than the invasion of aphids. It's rare to beat him in one season. When symptoms are noticed in the fall, it is worth postponing treatment measures until spring. When the snow melts, use hot water.
But with summer infection, postponing help for several months means significantly worsening the situation. It is recommended to immediately spray all currants that are sick with Bordeaux mixture, and cut off and burn the directly affected parts.
As already mentioned, ways to deal with terry have not been developed. There are only general recommendations for prevention:
- sanitary pruning in early spring;
- removal immediately after it even single old leaves;
- treatment of shrubs with boiling water;
- systematic weeding.
Of the drugs used to combat currant diseases, Bordeaux liquid is very useful. It effectively suppresses various types of spotting, rust and anthracnose. The same liquid also helps to avoid illness. The standard schedule implies processing immediately after flowering, then with a pause of 10 days. The last planned passage is done when all the berries are removed; of course, when symptoms of a lesion appear, it is necessary to process landings outside the schedule.
The preparation of a solution of Bordeaux liquid most often involves diluting it to 1%.For this purpose, take 0.1 kg of copper sulfate and 0.15 kg of quicklime. First, vitriol is dissolved in 3 liters of water. The same volume is used for lime slaking, while observing certain precautions. When both manipulations are done, vitriol is poured into lime, thoroughly mixed, filtered through a metal sieve and water is added to make 10 liters.
A good replacement for Bordeaux liquid is a solution of copper oxychloride (at a concentration of 0.3%) or systemic fungicides. As for the fight against anthracnose, the same Bordeaux liquid is used at a concentration of 1%. And from synthetic compositions, "Phytodoctor" is recommended. When using it, you can not deviate from the instructions. When glass rust appears, it is advisable to use phytosporin.
Returning to powdery mildew, it is worth emphasizing that some experts consider the use of iron sulfate to be the best option to combat it. 10 g of this reagent is dissolved in 30 liters of water. Such spraying should be done immediately after flowering. Then it is repeated 2 or 3 times, with a pause of 10 days. From natural mixtures, an infusion of humus helps. It is prepared by taking 1 part of the substance and 2 parts of water, it takes 2 days to infuse the drug.
If powdery mildew has completely captured a separate shoot, it will definitely have to be cut and destroyed. A similar approach is practiced for non-cryogenic drying. All cut points are supposed to be lubricated with garden pitch. The suppression of gray mold is achieved through the use of fungicides.
However, you need to have time to use them before the fruits are formed. The best option is to act when the plants bloom.
All about the diseases and treatment of currants, see the video below.