Blackcurrant leaves curl: what to do

Gardeners often encounter the fact that in the spring or at the height of summer, when the berries are still ripening, currant leaves suddenly curl. A bush that recently looked completely healthy can quickly 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 determine why the leaves are curling: due to fungal spores or the activity of insect pests. Timely treatment will help save the bush, and timely preventive measures will help prevent the situation from reoccurring next season.

Why do currant leaves curl?

A careful examination of the diseased plant will help you understand why curled leaves appeared on currants. Every detail is important:

• young or old leaves curl;
• are there any spots, what color are they;
• Is there a noticeable coating or cobweb;
• leaves curl inward or outward;
• what the reverse side of the affected plate looks like;
• whether there are growths, swellings, tubercles.

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

Often, it is enough to carefully unwrap the deformed plant organs to see the insect larvae inside.

Pests

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

leaf roller

A small (about 2 cm) brown moth, often with a dark pattern on the wings, which fold flat on the back. One butterfly can 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 the leaf blades, and after some time they curl into cocoons, covered from the inside with cobwebs. In the fall, after the damaged leaves fall off, the caterpillars pupate in them and overwinter. In the spring, butterflies will again emerge from the pupae and begin laying eggs on the currants.

Aphid

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

Currants are usually harmed by two types of this parasite:

1. Shoot (gooseberry) aphid – greenish color. Most often, it is this that causes the upper leaves of black currants to curl.First, the insect sucks the juice from the buds, then moves to the tops of the shoots. As a result, young leaves curl outward in shapeless lumps. Ants help spread aphids on currant bushes by feeding on honeydew, a sweet, viscous liquid that it secretes. They take the pest into the anthill for the winter, and in the spring they return it to the plant again.
   
2. Leaf (gal) The aphid lives on its own and prefers red or white currants. In mid-summer, the females develop wings, thanks to which the parasite is able to travel considerable distances, laying eggs near the plant buds in the fall. Insects that hatch from eggs in the 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 color. Leaves (both young and mature) quickly lose their shape, curl and die.
   

Spider mite

A tiny pest of yellowish-orange color, visible only through a magnifying glass: the size of the female reaches 1 mm, the male is half that size. The wind helps spider mites move. Colonies of this parasite live on the underside of plant leaves. At first, small light dots appear there. Over time, they form entire lesions that fade and then turn brown. The leaves dry out, curl and fall off.

Glassware

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

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

Currant gall midge (leaf and shoot)

Gall midge is a small (up to 1.5 mm) winged fly. The following types of currants are dangerous:

1. Currant leaf gall midge is yellow-brown in color. Lays eggs at the top of young shoots. The larvae that emerge from them eat the leaves, causing the tops of the shoots to curl, become “torn,” and gradually turn black and dry out. Mostly young bushes suffer.
   
2. Currant shoot gall midge, It is distinguished by a yellow-orange color and has brown stripes on the back. She lays her eggs in cracks in the bark. In places where colonies of larvae accumulate, the currant bark acquires a brown tint, spots and “dented” places appear on it. As the larvae drink the juices of the plant, the branches become brittle and quickly dry out, while the leaves on them curl and die.
   

Diseases

The reason why currant leaves curl may be a disease. Mostly this shrub suffers from fungal diseases. Knowing the symptoms of the most common ones will help you decide how to treat the plant.

Anthracnose

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

Spheroteka

This disease is otherwise called American powdery mildew. Its first manifestations can be noticed in May. The main symptom is a white coating, reminiscent of flour or pollen, clearly visible on young shoots, leaves, ovaries and berries. Gradually, the plaque thickens and turns brown, becoming similar to 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.

Septoria

You can also notice that currant leaves curl when the plant is affected by septoria (otherwise known as white spot). The cause of this disease may be poor ventilation of the bush due to the fact that excess branches that were not removed in time have grown.

The risk of septoria infection increases if:

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

A sign of the disease are numerous small grayish spots with brown outlines that appear on the leaves. Then dark inclusions (fungus and its spores) appear on them.The leaves quickly curl, lose color and fall off, the trunk becomes brown. This disease is dangerous not only for currants, but also for other garden 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-colored spores, which gradually darken and grow over the entire accessible surface. Infected leaves turn yellow, curl, and fall off prematurely.

Glass rust

Another common type of rust that is dangerous for currants is goblet rust. Infection with this disease occurs in early spring, but its first signs can be noticed on shoots, leaves, and flowers in early summer. Orange spots with small dark dots appear on the underside of the leaf blades. In their place, pustules and tubercles gradually form, shaped like glasses. Inside there is a brownish powder - fungal spores. Leaves suffering from rust curl and quickly fall off. A currant bush, weakened by disease, produces fewer shoots, bears less fruit and does not tolerate winter well.

How to treat currant leaves if they curl

Having determined what caused the curling of currant leaves, you need to start treatment as soon as possible.It should be remembered that currants are treated with chemicals, as a rule, before flowering and after harvesting. Between these stages, it is preferable to spray the bush with biological products or use folk recipes.

Chemicals

The strengths of fighting pests and diseases that cause currant leaves to curl using chemicals are high efficiency and quick achievement of results. However, it is important to carefully follow the instructions: do not exceed the recommended doses and adhere to the specified time frames for processing plants. It is advisable to use chemicals if the currant leaves are severely damaged and it does not make sense to use safer means (folk, biological products).

If 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, which manifest themselves in currant leaves curling:

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 treating currants when their leaves curl, if:

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

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, whose leaves curl, only at the “pink bud” stage and immediately after flowering.

Folk remedies

To treat damage and diseases of currants (including those that cause its leaves to curl), folk recipes for infusions and decoctions, mainly plant-based, are also used. Their effectiveness is not as high as that of biological and, especially, chemical drugs, 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 treating currants whose leaves curl are the following (proportions are indicated per 10 liters of water):

1. Onion and garlic. 100 g of purified ingredients must be cut as finely as possible and filled with hot water. Leave for 24 hours, then strain and spray with currant leaves (this amount is enough for 2-3 bushes).Use to combat aphids, leaf rollers, caterpillars and insect larvae.
2. Tobacco leaves. You will need 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 damage to currant leaves by aphids or glass flies.
4. Tomato tops. Pour 3 kg of fresh crushed leaves, stems and stepsons (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 bush curl 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 left for a couple of hours. Strain the tincture. Treat currants whose leaves are curled 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 and leave for 5 days. Add liquid laundry soap. Spray currant leaves that curl as a result of spheroteca infection. Also used in the fight against aphids.

You can also learn about various methods of treating currants from pests and fungal diseases (including those that cause leaves to curl on the bushes) at different stages of plant development from the video:

Agrotechnical measures

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

• regularly remove and burn shoots and leaves affected by 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 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;
• if butterflies appear above the bushes, you need to treat the currants with folk remedies with a strong pungent odor (garlic or tobacco infusion);
• Be sure to pay attention to preventive measures - this will help avoid diseases and damage by parasites, which cause currant leaves to curl.

Preventive actions

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 of currants curl than to later eliminate the consequences of the disease 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 promotes 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 areas of infection or damage.
3. Before planting in the ground, currant seedlings need to be kept in warm (about 45 ° C) water for 15 minutes to disinfect them from parasitic insects.
4. You cannot plant coniferous plants next to currant plantings (they 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 bushes and mow overgrown grass.
6. Once every 2-3 years (more often if necessary), currant bushes should be thinned and rejuvenated, removing overgrown shoots.
7. Twice a year (in spring and autumn) you need to dig up the soil in the tree trunk circles, mulch it with the addition of wood ash, and apply fertilizing in a timely manner.
8. In early spring (before the buds appear), it is recommended to spray the currants with Bordeaux mixture or copper sulfate solution. This will help prevent fungal diseases.

Conclusion

Having noticed that the currant leaves are curling, 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 suitable medications and immediately treat the bush. When choosing remedies (chemical, biological, folk), one must take into account how severely the plant is affected, as well as in what phase of its development the treatment will be carried out.To prevent this from happening again in the future, special attention must be paid to preventive measures.

Recommended Posts

How to plant currant cuttings in the fall

Currant Green haze

Blackcurrant Bagheera

Black currant Veloy

Blackcurrant Perun

How to treat currants against aphids

Black, white, red, pink currants: the best varieties for the Moscow region

Black currant Dove: reviews, planting and care, cultivation

Rust on currants: how to fight, photo