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Terry currant, or reversion, is a common disease that does not respond to treatment. Therefore, every gardener should know about the first signs of an illness, measures to prevent its development and about the causes of its occurrence. With complete information, you can protect your site from the spread of terry and protect yourself from acquiring a sick seedling.
What is currant terry
Terry currant is a serious illness caused by mycoplasma - an organism that cannot be called a virus or a bacterium, since it occupies a kind of intermediate space. The disease is transmitted along with the sap of the plant. Despite the fact that there can be no direct sap flow between a healthy and diseased bush, the plants continue to become infected from diseased specimens. This is possible due to the activity of aphids and kidney mites. Infection can also occur when taking planting material from a diseased bush.
What is the danger of terry currant
The main danger of the disease is that it is incurable. There are no drugs and folk methods that could effectively combat terry. As a result, gardeners from year to year observe their currant bush and wait for the harvest, writing off the lack of berries on unfavorable growing conditions, improper care and spring frosts.
Terry is insidious also by the fact that it does not appear immediately. A seemingly quite healthy black currant bush can begin to bear fruit, but every year the berries become less and less, although the whole bush is flowering. From the moment of infection until clear signs of the disease appear, it can take from 2 to 4 years.
Causes of the disease
As mentioned above, the cause of the development of a disease called terry is the mycoplasma virus, the main carrier of which is the kidney mite, which infects the plant in spring and at the very beginning of summer. This is due to the fact that ticks that have successfully overwintered in diseased kidneys begin to colonize healthy buds and branches. The most dangerous period for a plant is the interval between the development of buds and the beginning of fruiting. At this time, the daily temperature does not drop below 10 degrees Celsius, which favors the spread of the carrier pest. The migration period lasts at least 2 weeks and maximum - 2 months, ticks enter the crop with gusts of wind, are carried by insects and birds.
There are other carriers of the disease:
- spider mite;
Attention! Terry currant is not transmitted with seeds and pollen of flowers, it is not infectious to humans when eating fruits taken from infected bushes.
Signs of terry currant
Terry black currant, the photo of which can be seen below, is an insidious disease, since it is quite difficult to identify it. For several years, terry may be present in currants in a latent form, and its first signs appear most often only after 3 years.
Symptoms of terry currant include:
- a large number of elongated shoots;
- lack of berries, both on individual branches and on the entire bush;
- changing the shape and color of flowers;
- lack of the usual aroma of currants;
- changing the appearance of sheet plates.
Attention! If there are dried and non-falling flowers on the shoots, then this also indicates the presence of terry.
What to do with the terry black currant
Treatment of terry black currant is impossible. The reversion action cannot be stopped by any biological or chemical agent, therefore the only way to fight the disease is to immediately destroy the bush. Unfortunately, we have to act drastically. Pruning under a stump, removing diseased branches and leaves is not able to stop the progression of the disease.
You can only protect yourself and your crop by taking preventive measures, which are concluded in protecting plants from the vectors of terry. The following preventive measures can be distinguished:
- Planting healthy seedlings. When choosing planting material, it is necessary to give preference only to proven points of sale and sellers.
- Compliance with quarantine. Since the disease does not manifest itself immediately, planted specimens should be under special supervision during the first 4 years. Only after this time can the purchased bushes be transplanted next to the old currant bushes and take planting material from them.
- Selection of varieties that are resistant to this disease.
- Inspection and destruction of currant bushes affected by terry. It is necessary to regularly conduct a thorough examination of the currants, paying special attention to this during the period of flowering completion. If even a single shoot with the existing symptoms of infection is found, it is necessary to completely remove the bush. After that, black currants cannot be planted on the site for another 5 years, since all this time the virus continues to live in the soil and is dangerous to the culture.
- Trimming. Many gardeners are too addicted to pruning blackcurrant bushes, as this allows them to grow a large number of basal shoots. But it is they who are of particular interest for pests, which are carriers of terry.
- Compliance with sanitary measures during pruning. A pruner, knife or other tool that processes currant bushes on the site must be disinfected. Having ennobled one bush, it is necessary to lower the inventory in boiling water or a manganese solution, and only then proceed to the processing of the next bush.
- Examination of currant buds. Every spring, as soon as the buds begin to swell, it is necessary to carefully examine them. Swollen kidneys and kidneys with irregular shapes should be suspected. It was in them that ticks could get through. If a similar problem is found, experienced gardeners recommend immediately removing the buds or the branches themselves (with a large number of affected specimens) and burning them. This must be done before the kidneys open. Only then can the spread of the disease be prevented.
- Treatment of shoots with boiling water. This method of combating terry is proven over the years. Black currant bushes are scalded with boiling water in late February - early March. At this time, the currant bushes are at rest, the buds are not yet swelling. At least 7 liters of boiling water must be poured onto each bush. It is pointless to carry out processing in the autumn. Scalding is carried out according to all the rules: the trunk space is covered with polyethylene, sanitary pruning is carried out, the shoots are tied into one sheaf, pouring is carried out from a watering can with a fine strainer with water at a temperature of 60 to 80 degrees.
- In addition to boiling water, you can arm yourself with a number of preparations for treating the currant bush from terry. The following means are suitable: lepidocide solution, colloidal sulfur, 1% bitoxidacillin solution. They can be applied several times. The first treatment is carried out in the period before flowering, when the buds are just beginning to form. The second - at the end of flowering, the third - after harvest.
- In addition to the above funds, you can use chemicals such as Fufanon, Akarin, Fitovert. They are used when a large number of ticks are found on the bush.
- It is also possible to use folk remedies that are able to cope with ticks and other pests-carriers of terry. Among the most effective and popular remedies is the infusion of garlic, tobacco dust, onion husks. It is also necessary to process black currants several times: before flowering, after it and at the end of the harvest.
- An important role is played by the increase in the immunity of currants. It is difficult to infect strong bushes of culture with terry, because they are not "popular" among pests, therefore they prefer weaker plants. To raise immunity, it is necessary to carefully look after the plant, apply fertilizers in a timely manner, mulch the soil, treat the shrub with immunostimulating drugs, a solution of molybdenum, manganese and boron.
Attention! The introduction of increased doses of mineral fertilizers with nitrogen and fresh manure leads to a reverse reaction. The plant is weakening, which puts it at risk of massive tick attack.
Experienced gardeners know that it is extremely difficult to defeat currant terry. Therefore, they increasingly prefer the choice of currant varieties that have some kind of resistance to the development of this disease. This makes it possible to reduce the amount of effort involved in currant cultivation and processing. Among the most persistent varieties are Zhelannaya, Memory Michurin, Success, Moscow Region, Neapolitan.
Important! There are no varieties completely protected from terry. The breeders have not yet managed to breed such a strong species, but the above varieties are quite resistant and relatively not susceptible to the causative agent of the disease. It is also believed that terry rarely develops on currant varieties that are resistant to kidney mite infestation.
Terry currant is a serious disease that can eradicate the entire culture on the site. It is especially dangerous in areas with dry or too humid climates. Therefore, in such regions, gardeners will have to pay special attention to the cultivation of currants.