Content
Currant blight, or reversion, is a common disease that has no cure. Therefore, every gardener should know about the first signs of the disease, measures to prevent its development and the causes of its occurrence. Having complete information, you can protect your site from the spread of terry disease and protect yourself from purchasing a diseased seedling.
What is currant terry
Currant blight is a serious illness caused by mycoplasma - an organism that cannot be called either a virus or a bacterium, since it occupies some kind of intermediate space. Diseases are transmitted along with plant sap. Despite the fact that there cannot be direct sap flow between a healthy and diseased bush, plants continue to become infected from diseased specimens. This is possible due to the activity of aphids and bud mites. Infection can also occur when taking planting material from a diseased bush.
Why is currant terry dangerous?
The main danger of the disease is that it is incurable. There are no drugs or folk methods that could effectively combat terry.As a result, gardeners watch their currant bushes year after year and wait for the harvest, attributing the lack of berries to unfavorable growing conditions, improper care and spring frosts.
Terryness is also insidious because it does not appear immediately. A seemingly healthy blackcurrant bush may begin to bear fruit, but every year there are fewer and fewer berries, although the entire bush is flowering. From the moment of infection until clear signs of the disease appear, it can take 2 to 4 years.
Causes of the disease
As mentioned above, the cause of the development of a disease called terry disease is a mycoplasma virus, the main carrier of which is the bud mite, which infects the plant in the spring and early summer. This is due to the fact that ticks that have successfully overwintered in diseased buds 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 fall below 10 degrees Celsius, which favors the spread of the pest vector. The migration period lasts a minimum of 2 weeks and a maximum of 2 months; mites fall on the crop with gusts of wind and are carried by insects and birds.
There are other carriers of the disease:
- spider mite;
- bedbugs;
- aphid.
Signs of currant terry
Black currant terry, a photo of which can be seen below, is an insidious disease, since it is quite difficult to identify.Terry may be present in currants in latent form for several years, and its first signs most often appear only after 3 years.
Symptoms of currant terry include:
- a large number of elongated shoots;
- lack of berries, both on individual branches and on the entire bush;
- change in the shape and color of flowers;
- lack of the usual currant aroma;
- changing the appearance of sheet plates.
What to do with blackcurrant terry
It is impossible to treat blackcurrant terry. The effect of reversion cannot be stopped by any biological or chemical drug, so the only way to combat the disease is the immediate destruction of the bush. Unfortunately, we have to take drastic action. Pruning under the stump, removing diseased branches and leaves are not able to stop the progression of the disease.
Preventive actions
You can protect yourself and your harvest only by carrying out preventive measures, which involve protecting plants from terry vectors. The following preventive measures can be distinguished:
- Planting healthy seedlings. When choosing planting material, you must give preference only to trusted 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 you replant the purchased bushes next to the old currant bushes and take planting material from them.
- Selecting varieties that are resistant to this disease.
- Inspection and destruction of currant bushes affected by terry. It is necessary to regularly conduct a thorough inspection of currants, paying special attention to this during the period of completion of flowering. If even a single shoot with existing symptoms of infection is detected, it is necessary to remove the bush completely. After this, 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 for the crop.
- Carrying out pruning. Many gardeners are too keen on pruning blackcurrant bushes, as this allows them to grow a large number of basal shoots. But it is they who are of particular interest to pests, which are carriers of terry.
- Compliance with sanitary measures when pruning. A pruner, knife or other tool used to process currant bushes on the site must be disinfected. Having refined one bush, you need to immerse the equipment in boiling water or a manganese solution, and only then begin processing the next bush.
- Inspection of currant buds. Every spring, as soon as the buds begin to swell, you need to carefully examine them. Suspicion should be raised by swollen kidneys, as well as kidneys with an irregular shape. These are where ticks could get into. If such a problem is discovered, experienced gardeners recommend immediately removing the buds or the branches themselves (if there are a large number of affected specimens) and burning them. This must be done before the buds open. Only in this case can the spread of the disease be prevented.
- Treatment of shoots with boiling water. This method of combating terry has been proven over the years.Blackcurrant 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 makes no sense to carry out processing in the autumn. Scalding is carried out according to all the rules: the tree trunk space is covered with polyethylene, sanitary pruning is carried out, the shoots are tied into one sheaf, dousing 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 currant bushes against terry. The following products are suitable: lepidocide solution, colloidal sulfur, 1% bitoxidacillin solution. They can be used 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 harvesting.
- In addition to the above remedies, you can use such chemicals as Fufanon, Akarin, Fitovert. They are used when a large number of ticks are found on a bush.
- It is also possible to use folk remedies that can cope with ticks and other pests that carry terry. Among the most effective and popular remedies is an infusion of garlic, tobacco dust, and onion peels. Black currants also need to be processed several times: before flowering, after it and at the end of the harvest.
- Increasing the immunity of currants also plays an important role. It is difficult to infect strong bushes with terry, since they are not “popular” with pests, so they prefer weaker plants.To boost immunity, you need to carefully care for the plant, apply fertilizers in a timely manner, mulch the soil, treat the bush with immunostimulating drugs, a solution of molybdenum, manganese and boron.
Resistant varieties
Experienced gardeners know that it is extremely difficult to defeat currant terry. Therefore, they are increasingly giving preference to choosing currant varieties that have some resistance to the development of this disease. This allows you to reduce the amount of effort put into growing currants and processing them. Among the most resistant varieties are Zhelannaya, Pamyat Michurina, Success, Podmoskovnaya, Neapolitanskaya.
Conclusion
Currant blight is a serious disease that can eradicate the entire crop on the site. It poses a particular danger in areas with dry or too humid climates. Therefore, in such regions, gardeners will have to pay special attention to growing currants.
