Currants are often susceptible to various diseases and pests. In your area, you can observe how fragrant currant leaves curl up from aphids or rust, and the berries fall for no reason before they are ripe. This also includes the terry nature of red and black currants. What kind of disease it is, why it occurs and how to cope with it, you should find out in advance.
Description and causes of the disease
Important! The main reason for infection of bushes with terry is the presence of currant bud mite.Infection with the parasite occurs during plantation renewal. Mites can be introduced during planting of new seedlings. Another option is to use untreated garden tools. If you trim the branches of an infected young tree and then a healthy bush, the disease will certainly be transmitted.
The kidney mite is only a carrier of the disease. The disease itself is the vital activity of a microscopic virus, which very actively develops in the vessels of the plant. Moving along with the juice along the shoots, it affects the entire bush. If in the first year of life the disease may not manifest itself, then as the currant gains strength, it begins to be suppressed by the microplasma virus. Then not only the foliage suffers, but also the inflorescences.
As a result of complete infection of currants with the causative agent of terry disease, the variety degenerates and returns to a wild-growing state. Another name for the disease is blackcurrant reversion.
Signs of terry
Terry blossom is a serious infectious disease of blackcurrant bushes, leading to degeneration of varieties and the plantings themselves. The disease can be detected by the following symptoms:
- The presence of a large number of branches with small leaves that do not have a specific currant smell.
- In addition to greenery, terry can be determined, and often this happens, by the flowers. If currants normally have yellow flowers, in the place of which a green berry appears after flowering, then a diseased plant has pinkish or purple flowers. We can say that they are empty; an ovary does not form after them.
- At the end of each shoot, defective three-lobed dark green leaves appear.
- Small veins are practically invisible on the leaves.
- A diseased bush blooms later, and very small berries are formed.
If you detect terry in time and begin treatment, then it is possible to save the berry plants. Otherwise, you will have to part with the new purchased variety of large currants before fruiting.
How does bush infection spread?
According to gardeners, not only the bud mite is a carrier of the virus, but also other insect pests:
- aphid;
- bugs are herbivorous;
- spider mite
Pathogenic microorganisms can spread during bush propagation: during cuttings, separation of lateral shoots. In any case, the planting material is already infected with the virus. It is difficult to determine the disease of young seedlings, since the virus may not manifest itself externally. But a year or two after planting, the plant will slowly die.
Methods to combat the defect
Terry disease is a very dangerous disease of berry plantations. You won't be able to get rid of it completely. Even if the plant is destroyed at the roots, the virus is still present in it. Therefore, it is impossible to graft young shoots onto a stump where a diseased bush grew.
Important! The virus can only be destroyed together with the bush.
Then how to deal with terry? The main thing is to protect your lands from the attack of the “enemy”, or to prevent an existing pathogen from spreading. First of all, this concerns the kidney mite:
- Treatment of viral terry black currant occurs by pruning shoots affected by the bud mite and removing diseased buds. In spring, mite settlements on the kidneys become especially noticeable. Before they have time to open, they become swollen and not dense. These buds should be cut off and destroyed. If there are a lot of buds, then the entire shoot is removed. The procedure must be completed before the buds open.
- Hot water is very effective in the fight against ticks. Infected shoots are cut back to healthy wood. The remaining branches are tied together and scalded with water, the temperature of which should be up to 80 degrees. Cuttings from diseased branches are always destroyed; in the spring you can burn them with last year’s foliage.
- To combat currant terry and spider mites, you can use special preparations that have insecticidal properties. These include: colloidal sulfur, Lepidocid solution, Bitoxibacillin, Fufanon, Akarin and others, which are sold in specialized stores. It is important to dose the product according to the instructions.
Red currant terry disease is similar. Accordingly, the treatment is the same. All the procedures described above can be used to preserve red and white currant plantings.
Traditional methods of combating terry
Among the folk methods of treating plants against bud mites and aphids, carriers of the virus, the following remedies are distinguished:
- tobacco dust, infusion;
- garlic infusion;
- infusion of onion peel.
All treatments should be performed only as pests are detected.
Preventive actions
It is very important to follow the following recommendations from experienced gardeners:
- When purchasing new seedlings, the material is carefully selected. The best purchases are considered to be seedlings from a nursery or from well-known and trusted gardeners.
- It is necessary to monitor the condition of the young animals, since outwardly the disease may not manifest itself for about 4 years. In this case, the purchased bushes are planted away from the adult berry plant.
- When propagating currants by cuttings, only healthy currant bushes are chosen as the mother plant.
- You should choose varieties that are resistant to diseases and pests.
- Shrubs are regularly inspected for bud mite damage.
- Timely and correct pruning. If the shoots are severely pruned, young shoots will appear from the root in large numbers. They attract pests, particularly mites and aphids.
Only an integrated approach will help cope with massive infestations of currant bushes with terry.
Any of the types and varieties of currants is annually attacked by a huge number of pests, but the most dangerous is the terry virus. It is insidious in that the only method of getting rid of it is the complete destruction of the plantings. Preventive measures are aimed only at combating its carriers.
