Blackcurrant leaves curl: what to do

Gardeners are often faced with the fact that in spring or at the height of summer, when the berries are still ripening, currant leaves suddenly twist. A bush that until recently looked completely healthy can rapidly lose up to half of its green mass: the affected leaf blades quickly lose color, dry out and fall off. To effectively combat this disease, it is necessary to correctly establish why the leaves are twisted: due to fungal spores or the activity of insect pests. Timely treatment will help save the shrub, and timely preventive measures taken will prevent a recurrence of the situation next season.

Why currant leaves curl

To understand why twisted leaves appeared on the currant, a careful examination of the diseased plant will help. Every detail matters:

• young or old leaves curl;
• are there spots, what color are they;
• is plaque, cobweb visible;
• leaves curl inward or outward;
• what does the reverse side of the affected plate look like;
• whether there are growths, swellings, tubercles.

The time of appearance of these signs on the leaves and shoots of currant also plays a role.

It is often enough to carefully unfold the deformed organs of the plant to see the insect larvae inside.

vermin

If the leaves of the currant twist into a tube or into a lump, this may well be the result of the activity of a number of parasitic insects.

Leaflet

A small (about 2 cm) moth is brown in color, often with a dark pattern on the wings, which fold flat on the back. One butterfly is able to lay up to a hundred eggs on the inner surface of currant leaves within a month, from which yellow or bright green caterpillars will subsequently hatch. They eat leaf blades, and after a while they twist into cocoons, tightened from the inside with a cobweb. In autumn, after the damaged leaves fall off, the caterpillars pupate in them and overwinter. In the spring, butterflies will again appear from the pupae, which will begin to lay eggs on the currant.

aphid

Another very common enemy of currants is aphids. These are colonies of small, inactive insects that feed on the juices of the leaves, which is why the latter turn yellow, dry out and twist.

Currants are usually harmed by two types of this parasite:

1. Shoot (gooseberry) aphid – greenish color. Most often, it is she who is the reason that the upper leaves of the blackcurrant are twisted. First, the insect sucks the juice from the kidneys, then moves to the tops of the shoots. As a result, young leaves curl outward in shapeless lumps. Ants that feed on honeydew, a sweet viscous liquid that it secretes, help spread aphids on currant bushes. They also take the pest to the anthill for the winter, and in the spring they return it to the plant again.

   

2. Leaf (gallic) aphids live on their own, preferring red or white currants. In the middle of summer, the females develop wings, thanks to which the parasite is able to travel considerable distances, laying eggs near the buds of the plant in autumn. Insects hatched from eggs in spring colonize the underside of currant leaves, feeding on their juice. As a result, characteristic bulges appear on the outer side of the plates, resembling “blisters” of brown-red or yellow colors. Leaves (both young and mature) quickly lose their shape, curl and die.

   

spider mite

A tiny pest of a yellowish-orange color, visible only through a magnifying glass: the size of the female reaches 1 mm, the male is half the size. The wind helps the spider mite move. Colonies of this parasite live on the wrong side of the leaves of plants. At first, small bright dots appear there. Over time, they form whole foci that fade, then turn brown. The leaves dry up, twist and fall off.

Glassmaker

A small butterfly with almost transparent wings and a black body, marked by three clearly visible transverse stripes of yellow. Lays eggs on currant bushes in damaged areas of the bark. Caterpillars, which appeared after 10-15 days, eat through the passages inside the shoots, feeding on their core. At first, damage to the currant bush is almost imperceptible, but the next year, by the time the larvae have matured, the damaged branches begin to die, and the leaves on them quickly dry and twist.

To date, no varieties of currants and gooseberries have been bred that are resistant to the activity of the glass case.

Currant gall midge (leaf and shoot)

Gall midge is a small (up to 1,5 mm) winged fly. For currants, its types are dangerous:

1. Currant gall midge yellow-brown color. Lays eggs at the top of young shoots. The larvae that emerged from them eat the leaves, which is why the tops of the shoots twist, become “torn”, gradually turn black and dry out. Mostly young bushes suffer.

   

2. Currant gall midge, different yellow-orange coloring and has brown stripes on the back. She lays her eggs in cracks in the bark. In places of accumulation of colonies of larvae, the currant bark acquires a brown tint, spots and “depressed” places appear on it. Since the larvae drink the juices of the plant, the branches become brittle and dry out rapidly, while the leaves on them twist and die.

   

Diseases

The reason that currant leaves are twisted may be a disease. Mostly this shrub suffers from fungal diseases. Knowing the symptoms of the most common of them will help determine how to treat the plant.

Antraknoz

This disease usually manifests itself in the middle of summer. Islands of brown-red spots first appear on the leaves, the area of ​​which gradually increases. Dark markings can also be seen on petioles and young branches, in rare cases even on berries. Gradually, currant leaves turn red and curl, then fall off. If anthracnose is detected, not only currants should be treated with chemicals, but also shrubs and trees growing near it. The disease negatively affects the winter hardiness, development and yield of a number of garden plants.

Spheroteka

In another way, this disease is called American powdery mildew. Its first manifestations can be seen in May. The main symptom is a white bloom resembling flour or pollen, clearly visible on young shoots, leaves, ovaries and berries. Gradually, the plaque thickens and becomes brown in color, becoming like mold. The leaves darken and curl, the shoots become deformed and stop growing, and the berries lose their taste and presentation. If treatment is not started in time, the currant bush will quickly die.

septoriosis

You can also notice that currant leaves curl when the plant is affected by septoria (otherwise – white spotting). The cause of this ailment may be poor ventilation of the bush due to the fact that extra branches that have not been removed in time have grown.

The risk of septoria is increased if:

• air humidity is increased;
• the bush grows in the shade.

A sign of the disease are numerous small spots of grayish color with brown contours that appear on the leaves. Further, dark blotches appear on them (the fungus and its spores). The leaves quickly twist, lose color and fall off, the trunk becomes brown. This disease is dangerous not only for currants, but also for other horticultural crops, since it can quickly spread over a large area.

columnar rust

The main symptom of columnar rust on currants is yellowish-orange spots that appear on the leaves. The disease appears in the middle of the growing season. The reverse side of the leaf blades is covered with dense growths with rusty spores, which gradually darken and grow over the entire accessible surface. Infected leaves turn yellow, curl and fall prematurely.

goblet rust

Another common type of rust dangerous for currants is goblet. Infection with this disease occurs in early spring, but you can notice its first signs on shoots, leaves, flowers in early summer. Orange spots with small dark dots appear on the underside of the leaf plates. In their place, pustules and tubercles gradually form, resembling goblets in shape. Inside is a brownish powder – spores of the fungus. Leaves that suffer from rust curl and fall off quickly. The currant bush, weakened by the disease, produces fewer shoots, bears less fruit and does not tolerate winter well.

How to process currant leaves if they curl

Having determined what caused the currant leaf curl, you need to start treatment as soon as possible. It should be remembered that the treatment of currants with chemicals, as a rule, is carried out before flowering and after harvesting. Between these stages, it is preferable to spray the shrub with biological products or apply folk recipes.

Chemicals

The strengths of the fight against pests and diseases, due to which the leaves of the currant are twisted, with the help of chemicals are high efficiency and quick results. However, it is important to carefully follow the instructions: do not exceed the recommended doses and adhere to the specified terms for processing plants. It is advisable to use chemicals if the currant leaves are severely affected and it makes no sense to use safer means (folk, biologicals).

If the currant leaves curl as a result of the activity of parasitic insects, chemical insecticides will be effective against them:

Chemical fungicides will help to cope with fungal diseases, manifested in the fact that currant leaves are twisted:

Biological agents

Unlike chemicals, the action of biological products is more gentle. These products contain live microorganisms (viruses, bacteria, fungi).

Biological products are suitable for processing currants when their leaves are twisted, if:

• the disease was detected at the initial stage;
• the number of insect pests is low.

The vast majority of biological products are effective only at the appropriate air temperature (+ 10-15 ° C). Accordingly, it is possible to use them in the treatment of currants, in which the leaves are twisted, only at the stage of the “rose bud” and immediately after flowering.

Folk remedies

For the treatment of injuries and diseases of the currant (including those that result in the twisting of its leaves), folk recipes for infusions and decoctions, mainly plant-based, are also used. Their effectiveness is not as high as that of biological and, moreover, chemical preparations, and the effect will have to wait, but they will not cause any harm to plants, animals and humans.

Among the most effective folk remedies for the treatment of currants, in which the leaves are twisted, are the following (the proportions are based on 10 liters of water):

1. Onion and garlic. 100 g of purified ingredients are required to be cut as small as possible and pour hot water. Infuse for a day, then strain and spray currant leaves (this amount is enough for 2-3 bushes). Use to control aphids, leafworms, caterpillars and insect larvae.
2. Tobacco leaves. It will take 400 g of their dry powder, which must be filled with water and left for 2 days. Then pour another 10 liters of water into the composition and add about 80 g of laundry soap shavings. Strain and use if currant leaves curl and turn black as a result of aphids or spider mites.

   

3. Celandine. You should take 3-4 kg of fresh or 1 kg of dry grass. Pour hot water and leave for 1,5 days. It will help with the defeat of currant leaves by aphids or glassware.
4. Botva the tomato. Pour 3 kg of fresh crushed leaves, stems and stepchildren (or 1 kg of dry raw materials) with water and leave for 3-4 hours. Next, boil the composition for half an hour, cool and dilute with water in a ratio of 1 to 4. It is effective if the leaves of the shrub are twisted due to the activity of the currant gall midge.
5. Dandelion. 400 g of leaves and roots of the plant should be poured with hot water and kept for a couple of hours. Strain the tincture. Process currants whose leaves are twisted due to aphids.
6. Iodine solution (10 ml per 10 liters of water). Effective against powdery mildew (spheroteca).
7. Wood ash. Stir 1 kg of powder in a bucket of water, leave for 5 days. Add liquid laundry soap. Spray the leaves of the currant, which are twisted as a result of damage by the sphere library. Also used in the fight against aphids.

You can also learn about the various methods of processing currants from pests and fungal diseases (including those from which leaves curl on the bushes) at different stages of plant development can also be found in the video:

Agrotechnical measures

If the currant leaves are twisted, then the fight against the disease or pests is not limited to spraying the plant with various compounds. The gardener needs to take other actions:

• regularly remove and burn shoots and leaves affected by the disease or larvae;
• under the currant bushes, it is worth planting some medicinal plants (yarrow, marigolds, tansy), as well as dill: they attract ladybugs, lacewings, hoverflies, which will help to cope with aphids, spider mites and other pests;
• with the help of feeders and drinkers, attract birds (tits, sparrows) to the berry garden;
• it is necessary to destroy anthills at the roots of the plant, and it is recommended to treat the lower parts of the branches on the bushes with special garden glue;
• in the event of the appearance of butterflies above the bushes, it is necessary to treat currants with folk remedies with a strong pungent odor (garlic or tobacco infusion);
• be sure to pay attention to preventive measures – this will help to avoid diseases and parasites, from which currant leaves curl.

Preventive measures

Prevention of diseases and pests is the key to a healthy and productive berry garden. It is easier to prevent a situation in which young and mature leaves curl in currants than to later eliminate the consequences of an illness or the destructive activity of insects.

Basic preventive measures:

1. When planting currants on the site, you need to ensure that the distance between the bushes is at least 70-80 cm. This contributes to good ventilation of the plants, allows the leaves to receive enough sunlight and heat, and also dry quickly after rain.
2. All planting material must be healthy, without visible places of infection and damage.
3. Before planting in the ground, currant seedlings should be kept for 15 minutes in warm (about 45 ° C) water to be disinfected from parasitic insects.
4. It is impossible to plant coniferous plants next to currant plantings (contribute to infection with goblet rust), as well as gooseberries (suffer from the same diseases and pests as currants).
5. It is necessary to get rid of weeds under the bushes, mow overgrown grass.
6. Once every 2-3 years (more often if necessary), currant bushes should be thinned out and rejuvenated by removing overgrown shoots.
7. Twice a year (in spring and autumn) you need to dig up the soil in the near-stem circles, mulch it with the addition of wood ash, and fertilize in a timely manner.
8. In early spring (before the buds appear), it is recommended to spray the currants with Bordeaux liquid or a solution of copper sulfate. This will help prevent fungal diseases.

Conclusion

Noticing that the leaves of the currant are twisting, you need to try to understand as soon as possible what caused this symptom. Having identified a fungal disease or identified a parasitic insect, you should select the appropriate drugs and immediately treat the shrub. When choosing means (chemical, biological, folk), one has to take into account how badly the plant is affected, as well as in what phase of its development the treatment is to be. In order to prevent this from happening in the future, special attention must be paid to preventive measures.