Diseases of black currant
How to identify diseases of black currant and fight them for the sake of high yields of this crop
In black currant, the most common and harmful are fungal diseases (mycoses) - spots (anthracnose and septoria), rust (goblet and columnar) and mycoplasma - terry. They are a serious reason for the weakening of the fruiting and productivity of the bushes of this culture.
Brown spot of currant
Mottling are found in almost every garden plot, but the time of their manifestation is largely associated with the weather conditions of the growing season. Severe damage to plants by these diseases reduces the assimilation surface of the leaves and leads to premature leaf fall in the middle of summer, to a deterioration in the quality (decrease in sugar content) of berries, to a weak growth of annual shoots and a strong weakening of plants. Affected bushes hibernate poorly, reduce immunity to damage by other pests and diseases, as well as to the effects of adverse weather conditions.
Anthracnose (brown spot) mark on leaves, petioles, young shoots and berries. On the leaves, the fungus forms small rounded spots, on the surface of which black tubercles with sporulation appear: when they break, they take the form of white grains. Light brown dots with a red border are fixed on the berries. Anthracnose causes early leaf fall and the death of young shoots. The disease develops strongly in the second half of summer. Intensive development of the disease is typical for a rather humid summer with low temperatures; in seasons with hot and dry weather, the disease develops weakly.
In black currant, the varieties Belorusskaya Sweet, Golubka, Imandra-2 show the greatest resistance to brown spotting. It should be noted that this disease also affects all types of currants and much weaker - gooseberries.
From septoria (white spot) leaves, stems and berries are affected. At the beginning of the disease, small rounded spots of a bright brown color appear on the leaves, which expand and merge with severe damage. Later, lightening of these spots is observed (but with the appearance of a dark brown border), in the center of which (on the upper side of the leaf) small black dots are clearly visible - fruit bodies with spores: with their help, the fungus multiplies. On the shoots there are elongated spots of the same color, over time they crack and deepen, resembling ulcers in appearance. Flying away, spores infect more and more new leaves and shoots. Fruits are affected by septoria shortly before ripening: small, depressed brown specks appear on the berries.
White spot is especially harmful in seasons characterized by high temperatures and humidity in the spring and summer, as well as in thickened plantings. If weather conditions are favorable for the development of the disease, yield losses can exceed 50%.
There are no black currant varieties resistant to septoria blight; the Belorusskaya Sweet and Yunnat varieties are characterized by a lower susceptibility. There are varieties of currants that show complex resistance or low susceptibility to both mycoses: Memory Vavilov, Binar, Veloy, Poetry, Heiress and Detskoselskaya ... Red currant suffers from septoria weaker (less often gooseberries are affected).
Spot control measures the currants are the same. To prevent them, it is required: to maintain the optimal distance between the plants, to prevent thickening of the bushes (to thin out and remove the affected and damaged shoots) and timely destroy the weeds that create high humidity in the bushes.
To increase the resistance of plants in the spring, it is recommended to apply complete mineral fertilizer together with microelements (0.6 g of zinc, copper, manganese sulfates per 1 m²) with incorporation into the soil. Plant immunity can also be increased by spraying the leaves in June (foliar feeding) with a solution of a mixture of fertilizers (1-2 g of copper sulfate, 2 g of boric acid, 5 g of manganese sulfate, 3 g of zinc sulfate, 3 g of ammonium molybdate per 10 liters of water) or already finished preparations containing trace elements (you need to carefully monitor the preparation of the concentration of the solution in order to prevent burns of young leaves). In the fall, to reduce the stock of wintering infection, fallen leaves are composted or, when digging the soil under the bushes, they are stratified with earth.
Goblet currant rust
Goblet rust manifests itself on leaves, petioles, flowers and ovaries of currants, on which orange-yellow pads with goblet depressions are formed. This disease is interesting in that it develops on currants in the first half of summer, and then seems to disappear: it changes the owner and passes to sedge, which grows on swampy or highly moistened soils. Despite this "migration", goblet rust is very harmful to currants and in the years of epiphytoties causes a strong leaf fall and a large damage to the ovaries, which leads to the loss of a significant part of the berry harvest. The disease also affects red currants and gooseberries.
Columnar rust affects only currant leaves: chlorotic spots are visible on the upper side, orange pustules on the lower side, which can densely cover the leaf blade by the end of summer. Affected leaves turn brown, dry out and fall off prematurely. The mass development of the disease is noted during the period of flowering and the formation of ovaries (especially in warm and humid weather). The fungus is able to successfully winter on leaves under a 5-7 cm layer of earth.
To reduce the prevalence of these types of rust, the use of the same agricultural techniques as for the control of spots helps. In the summer, you can use three times spraying the bushes before flowering against the pathogens of anthracnose, rust and septoria, the most important treatment; immediately after flowering, but no later than 20 days before harvesting the berries; after harvesting fruits with a 1% solution of Bordeaux mixture, the versatility of which also lies in reducing the harmfulness of pathogens of many other fungal and a number of bacterial diseases.
Terry black currant
Terry black currant - the most dangerous, very harmful disease. In the north-west of the country, it causes significant damage to blackcurrant plantings, "mowing" almost all the most common high-yielding and good-tasting varieties.
The disease is easily recognized by diseased (modified) flowers. Affected flowers become, as it were, transparent (from white-yellow to purple), ugly, double and fall off before the formation of fruits. In diseased plants, narrow, small leaves with few veins are also observed, making the leaf appear wrinkled.
Often, young leaves from five-lobed become three-lobed, acquiring a dark green color and losing a specific smell. Lateral buds do not form flower clusters, but vegetatively thickened shoots. Diseased bushes degenerate: they become sterile or are characterized by a significant decrease in the yield of berries.
The causative agent of the disease spreads with planting material; the carrier of mycoplasma is kidney currant mite.
Sometimes terry is called "Reversion"; this name is associated with two characteristics of the disease: firstly, it means a condition in which the distinctive features of the leaves change (the whole bush looks like it has returned to the appearance of its wild ancestors), and secondly, in some years the disease is, as it were, masked (not appears for a year or two), then returns again (“reversed”).
Currant varieties are characterized by unequal resistance to terry and fruit mites, but, in my opinion, it is advisable to select varieties on a personal plot mainly according to the first indicator. It is known that black currant varieties Odzhebin, Altai, Vystavochnaya, Leningrad giant, Izmailovskaya are affected by terry and mites to a strong or medium degree.
The black currant variety Doveka is resistant to terry, but is damaged by a tick. The varieties of black currant Pilot A. Mamkin and Belorusskaya Sweet are weakly susceptible to ticks (and to fungal diseases); varieties Vologda and Volodinka are not resistant to ticks.
Although the listed varieties are not bad varieties in their basic qualities, gardeners need to take these characteristics into account for their resistance to these harmful objects. To increase the resistance of plants to this mycoplasma disease (also to limit it), experts recommend adhering to the rules of high agricultural technology: applying potash fertilizers, observing the correct watering dates, and treating the soil in a timely manner. You should purchase only healthy planting material, beware of buying it from random people. You can not harvest cuttings from tops, basal shoots and bushes affected by a tick.
Sometimes the fight is carried out with the tick itself in early spring: by plucking out the swollen buds inhabited by this pest. Pruning plants under the root (under the "stump") before budding can give a positive effect in the fight against currant mites, but it does not allow to save an already infected bush from terry and thus get away from the causative agent of the disease itself. Plants heavily affected by this mycoplasmosis must be uprooted and burned; at the same time, crop rotation should be observed: new bushes are recommended not to be planted in the same hole, but to retreat at least a meter or to occupy this area with another agricultural crop.
candidate of biological sciences,
Senior Researcher, All-Russian Research Institute of Plant Protection,
7 SECRETS TO A GOOD HARVEST OF BLACK CURRANT
Secret 1: tricky strategy
If we want the harvest to be "guaranteed", the most correct way is to plant several varieties of currants on the site, which bloom at different times. Then, with spring frosts, most likely not all currant color will suffer.
Secret 2: spacious "living space"
It is recommended to plant currant bushes no closer than 1 meter from each other. Some experienced gardeners consider a distance of 2 meters to be optimal. If the distance between the bushes is less than 1 meter, the yield decreases, and the life expectancy of the bushes is reduced. When planting currants along the fence, the recommended distance from it is 1.2 meters.
The fact is that currants are not indifferent to starch. Therefore, to increase the yield, a special top dressing is used:
Recipe: Potato Peel Infusion
pour a full 1-liter jar of dried potato peel into 10 liters of boiling water. Close the lid and wrap it up to cool down longer.
This top dressing is most effective during the flowering period. The recommended rate is 3 liters of infusion per 1 currant bush.
Secret 4: tricky delivery of fertilizers to the roots
You can simply sprinkle mineral fertilizers under the bushes, and then sprinkle with water. You can dissolve fertilizers in water and water the soil with a solution.
Secret 5: bush health and prevention
It often happens this way: even with a lot of currant bushes, the summer resident collects a very small crop of berries. And the reason for this is pests and diseases. Aphids, ticks, scale insects and powdery mildew can almost completely deprive us of the currant crop. Meanwhile, you can prevent the enemy from entering your territory with very simple methods:
do preventive examinations of the plant and immediately remove the affected buds, leaves, shoots
in early spring, before the soil under the bushes has completely thawed, it is good for the currant bushes to make a hot douche. To do this, pour boiling water into a spray can and simply pour over the plants. Such a hot shower can destroy the eggs of the kidney mite and scale insects. And it will also be an excellent prevention of powdery mildew.
during the budding period, the bushes are recommended to be sprayed with Bordeaux liquid
can be used for spraying herbal infusions - chamomile, dandelion, marigolds, tobacco. And how to get rid of aphids with celandine, Olga Platonova will tell in the next video
Secret 6: good watering
Currant is a moisture-loving plant, and it must be watered. If there is not enough moisture, the growth of shoots slows down significantly, the berries become small. And after the autumn moisture deficit, the bush will endure the winter much worse.
The root system of the currant is fibrous, and the bulk of the roots is shallow - from 10 to 60 cm, so watering is necessary. But often you don't need to water it. You can do this 4-5 times per season - for example, during the active growing season during flowering and the formation of ovaries during the period of berry filling and after harvesting.
If the summer is dry and hot, water the currants at least after 7-10 days. The norm in this case is up to 50 liters for each bush. Experienced gardeners advise to dig circular grooves around the bush (about 20-25 cm from the ends of the stems), and pour water into them.
Secret 7: our friend is a pruner
To maintain a currant bush in a good, healthy, fruiting state, it must be pruned. Pruning helps shape the shrub and maintain the correct age-to-branch ratio. Pruning can be done in spring or fall, but fall is considered the best time to do this.
Tips from experienced summer residents
Do not plant currant bushes "close to" the fence. The part of the bush pressed against it will not give you fruit!
The currant is a self-pollinating plant, if you plant other varieties nearby, cross-pollination will lead to an enlargement of the berries.
Black currant does not like soil with high acidity, if you have it on your site, you need to liming.
You should not plant currants in lowlands with excessive moisture - there they feel uncomfortable and will not give a good harvest.
So that the bush always remains young and productive, so as not to get confused in shoots of different ages, there is a trouble-free and even fascinating method.
Diseases of black currant
Black currant is one of the most unpretentious dacha crops. Summer residents are especially attracted by the fact that its bushes can be successfully grown in almost all regions. With proper care, a great harvest of healthy berries can be harvested in July.
The planted shrub yields a harvest already in the second year of life. Moreover, the minimum fruiting period is 8-10 years. Therefore, every grower wants to keep the black currant bush as long as possible. For this, it is important to protect the plant from diseases and pests. We will consider how to do this correctly further.
The causative agent of the disease is a fungal infection. Its first signs can be seen in the middle of summer. First red and brown spots appear on the leaves,which gradually increase in size, after which the leaves dry out completely and fall off.
The disease occurs on bushes of all types, but most often affects red currants. The fungal infection is most active in cool and rainy weather. When the first signs of anthracnose appear, treatment should be started immediately. For this, Bordeaux liquid is used. She should spray the bushes at the first symptoms, as well as after harvest.
Treatment is not always effective, after which preventive measures should be followed. Young bushes should not be planted in the same area where currants affected by anthracnose grew.And all fallen leaves and damaged branches must be burned.
Diseases and pests of currants
The disease affects the leaves of black currants and gooseberries, and in red currants - leaf petioles, stalks and fruits. Anthracnose develops in early May. First, small brown spots appear on the leaves with darker colored edges. Gradually they grow in size and merge together. The affected leaves turn yellow, curl upward and fall off prematurely, the shoots are stunted and do not ripen.
In the fight against anthracnose, it is important to dig up the soil in late autumn and early spring around the bushes with the incorporation of fallen diseased leaves.
Of the chemical means of protecting currants, positive results are obtained by spraying with a solution of iron or copper sulfate before bud break (respectively, 300, 50-100 grams per 10 liters of water). During the growing season, a four-time spraying with one percent Bordeaux liquid is carried out. It is important in this case that the liquid gets on the top and bottom sides of the sheet. The first spraying is carried out during bud break, the second - immediately after flowering, the third - 10-15 days after the second, and the fourth - after harvesting.
A common currant disease in the country. Orange spots appear on the underside of the leaf - pads. During the period of exacerbation of the disease, the leaves fall off, the bushes weaken, the yield decreases.
Currants should not be planted in places where sedge grows, and when planting, thicken the bushes. The site is kept in a weed-free condition. In the fall, the soil is dug deeply, embedding autumn leaves in it. In addition, the bushes are sprayed with a solution of iron or copper sulfate, as well as Bordeaux liquid, as in the fight against anthracnose.
A fungal disease that affects the leaves of currants and gooseberries. It appears on them in the form of grayish rounded or angular spots with a dark brown border and black dots in the center.
Control measures. The same as against anthracnose.
A viral disease that spreads very quickly. The disease is carried by currant kidney mites, aphids, bedbugs. With a disease of terry, the shape and color of the flowers changes. The leaves of diseased plants also change. The lobes of the leaf become narrow, pointed, the denticles greatly increase and stand out sharply on the leaf blade. The flowers turn purple and become double. Sepals and stamens turn into petals. Leaves from five-lobed become three-lobed. Currant bushes infected with terry do not bear fruit. The disease is transferred with the planting material.
For the establishment of new plantings of currants, only healthy planting material is used. Branches affected by terry are cut off, and sometimes the entire bushes are removed. In addition, they must fight the kidney mite.
It affects all types of currants. Yellow-red convex galls are formed on the upper side of the leaves.
- Currant glass jar.
Its larva makes holes in the inner part of the black currant twigs, which it feeds on. Hibernates in paved passages.
- Currant gall midge.
Its larva damages, strongly deforms or completely dries out young leaves on the tops, on the main branches and ramifications.
- Kidney mite.
Destroys flower buds and is a carrier of the most dangerous viral disease - reversion.
Branches and twigs affected by glass and kidney mites are cut out and burned, repeating the operation after 15-20 days.
After the leaves fall, they are buried or collected and burned - against anthracnose, septoria, gall midge, etc.
Winter spraying is carried out with a 1.5% solution of dinosol - against all diseases.
With the massive appearance of gall midges in the second half of March, the soil surface under the bushes is sprinkled with 2.8% lindane at the rate of 3 g / m2.
After flowering, they are sprayed with a 0.1% solution of basezol, a 0.1% solution of caratan or a 0.8% solution of thiosol (if the plants are not damaged by powdery mildew, they can be replaced with a 0.3% solution of perocin) in combination with a 0.3% chlorophos solution, 0.12% dipterex solution or with another insecticide - against anthracnose, septoria, powdery mildew, glass, gall midge, etc.
A 0.2% milbol solution, a 0-2% thionex solution are used against the kidney mite.
1 Dangerous viral infections - we recognize mosaic and doubled leaves
If currants begin to bear fruit poorly, and their leaves suddenly turn yellow, the problem is not only drought or improper care. The source of infection can be a wide variety of reasons. First of all, take a closer look at the sheet plates. Yellowing along the main veins is a signal of the onset of a dangerous viral disease - striped or veined mosaic. Unfortunately, if your currant has become a victim of this virus, it cannot be cured. We'll have to dig up and burn the bush, and treat the place where it grew with a strong solution of potassium permanganate. To prevent this disease in the future, buy planting material only in proven nurseries, and also fight pests, in particular with gall aphids - the main vector of the mosaic virus.
Signs of veined mosaic
Terry is considered the second dangerous virus that leads to disruption of fruiting functions and deformation of leaf plates. The edges of the leaves infected with the virus become ribbed and asymmetrical, and become significantly denser. The number of veins on them also decreases, the petals on the flowers become narrow, sometimes the shrub acquires a purple tint. The fruit-bearing functions of the currant are lost. As in the case of mosaics, pests, such as kidney mites, also transfer terry from a diseased kidney to a healthy one. Therefore, it is necessary to remove such buds in time so that later you do not have to uproot the entire bush.
As a prevention of infection with the virus, purchase a healthy seedling, and after collecting all the berries from the bush, treat it with Karbofos, colloidal sulfur. Fertilize black currants with potash-phosphorus mixtures, this will increase its resistance to terry. But you should not get carried away with nitrogenous fertilizers, they, on the contrary, provoke the development of the virus.
Did you know that the word currant comes from the word currant, which means a strong smell. Indeed, a pleasant berry aroma emanates from all parts of this shrub, which persists even after picking berries and severe frosts.
Currant pests and control
Pests of currants and the fight against them cause a lot of inconvenience to gardeners, photos of parasites will help to recognize them in a timely manner and begin treatment at the initial stage of the lesion. Insects can simultaneously infect all varieties of crops available on the site, destroying leaves, shoots and berries.
This culture is most often affected by leaf gall aphids. Small insects reach no more than 2 mm in length and feed on plant juices. The main signs of the presence of a pest:
- large spots in the form of swellings are formed on the leaves, painted in yellow or red
- gradually the leaves dry out and die.
Another type of aphid is shoot. It attacks branches, bending them and inhibiting growth. The insect lives throughout the summer, and during this period it can change up to 7 generations. The best remedy for aphids is Actellic or Karbofos. Spraying is done in accordance with the instructions. The procedure is repeated after 10 days.
You can avoid damage to berry bushes thanks to the following preventive measures:
- remove weeds and fallen leaves regularly
- prune diseased bushes
- attract insects that feed on aphids (such as ladybugs). For this, plants such as daisies, tansy or yarrow are planted nearby.
A small gray fire butterfly reaches 1 cm (wingspan up to 3 cm). Pupae easily endure winter in the soil under a bush, and during flowering, butterflies strike flowers, laying eggs in them.
Currant pests, photo of Ognevka
The main symptoms of the presence of a pest:
- hatched caterpillars on a bush feeding on berries
- the fruits are entwined with cobwebs.
The affected plant cannot be cured. The only way to protect the bush from fire is to cover the soil around it with roofing material or linoleum before flowering, so that the pest cannot get out on it. When the culture fades, the shelter can be removed.
One of the most dangerous pests is the kidney mite. We considered methods of fighting and protecting currants from this parasite earlier, in our article: How to get rid of a kidney mite on currants
Many gardeners like to grow such useful berries as currants in their summer cottages. Unfortunately, she is often exposed to diseases caused by various fungi and parasitic insects. To save the bushes and preserve the harvest, it is necessary to determine the disease in time and begin treatment with the recommended drugs.
If the plant cannot be cured, it must be urgently removed and burned. Observing all the rules of agricultural technology for growing currants, and regularly carrying out preventive treatment, damage to the bushes can be easily avoided.