Blackberry diseases and their treatment, photo

Cultivated or garden blackberries have recently become widespread in household plots in Russia. Its most common and popular varieties originate from America or Western Europe, where weather conditions differ significantly from Russian ones. In this regard, disease resistance, which is actively advertised in descriptions of blackberry varieties, may be somewhat exaggerated. And since experience growing blackberries and the fight against its various ailments in our country has not yet been sufficiently accumulated, then we have to mainly focus on its closest relative - raspberries.

Classification of blackberry diseases

Like most representatives of the plant kingdom, all possible diseases of garden blackberries are divided into four main groups:

Non-infectious – are caused by various unfavorable weather conditions and errors in care.
Fungal - are caused by fungal microorganisms, the spores of which are capable of moving in all unimaginable ways: with the help of wind, rain, pests, on tools, clothing and, of course, on various plant organs.
Bacterial – are caused by dangerous bacteria that live mainly in the soil.
Viral – are caused by viruses, which can spread in a variety of ways, but are most often transmitted through insect pests.

In general, insect pests play a significant role in the spread of diseases on blackberries, but in more detail about blackberry pests and control methods you can learn about them from the article posted in another section.

Fungal

Diseases caused by fungal spores are the most numerous of all that blackberries can be susceptible to. In 80% of cases of problems with blackberries, we can say with confidence that they were victims of one or another fungal disease. The main signs of fungal diseases are spots on the leaves and stems of blackberries of various sizes, shapes and colors. Spores of fungal diseases penetrate blackberry tissues through lenticels, stomata and wounds and scratches on the above-ground parts of plants.

Septoria (White spot)

The causative agent is the fungus Septori Rubi West. The source of infection is most often diseased planting material.

The disease may be completely absent in hot and dry summers, but it will manifest itself in all its glory with an abundance of rainfall and moisture, especially in thickened blackberry plantings. The first signs of septoria appear at the very end of spring - beginning of summer, first on last year's shoots. The easiest way to notice them is on the leaves - small light brown spots gradually turn into white with a dark border.On the shoots, almost imperceptible light brown spots appear around the buds and internodes. The disease actively spreads throughout the summer season, and by August the leaves and shoots are covered with small black dots, which are the fruiting bodies of the fungus.

The consequence of the disease is a slowdown in the movement of nutrients through the tissues of shoots and leaves, a delay in development and shoot formation. As a result, the harvest of the current and next year suffers. The berries are crushed, do not ripen and rot.

The most important thing among the methods of combating the disease is to immediately cut off and immediately burn the affected shoots with leaves. The spread of the disease can be facilitated by excessive fertilizing with nitrogen fertilizers, so make sure that the blackberries are properly fed.
Before the buds open, it is necessary to carry out preventive spraying of blackberry bushes with a 1% solution of Bordeaux mixture.
Spraying blackberries 3 to 5 times per season with a solution of Fitosporin (5 g per 10 liters of water) will also help as preventive measures.
When the first signs of the disease are detected, the leaves and stems of the blackberry should be generously sprayed with a solution of Alirin B and Gamair (1 tablet of each biological product is dissolved in 1 liter of water).

Anthracnose

The disease is spread by the fungus Gloeosporium venetum Speg. Fungal spores are found in soil or plant debris.

Anthracnose is also particularly active in damp and cool conditions; excessive watering can contribute to the manifestation of the disease.

All parts of blackberries are susceptible to the disease, but leaves, shoots and petioles are especially affected. The first signs can be observed at the very end of spring.

The leaves along the edges and along the main veins are covered with gray-violet spots of uneven shape up to 2-4 mm in size. At the bottom of the replacement shoots and root shoots you can see elongated purple spots with cracks in the middle. Over time, they become dirty gray with peeling bark around them. The fruit branches completely dry out and die, and when it comes to fruits, they do not ripen, dry out and fall off.

Purple spot (Didimella)

The causative agent of the disease is the fungus Didimella applanata Sacc. Warm, wet winters, as well as spring and summer with high rainfall, favor the development of the disease.

Didimella primarily affects not the leaves, but the young shoots, petioles, and buds, so it is quite difficult to notice it in time. The leaves are not affected as severely as in the case of other diseases.

First, in the lower and middle parts of the blackberry shoots, purple spots of a vague outline appear, which can grow quickly and become dark brown. They appear mainly in the places where the petioles are attached, which are also covered with similar spots. The blackberry bark in the affected areas becomes covered with cracks, the buds dry out, young shoots wither, the leaves, covered with dark spots with a yellow border, fall off.

Flowering can be very sparse, and a minimal number of ovaries are formed, which, of course, affects the harvest. However, the quality of the berries leaves much to be desired - they ripen poorly and have a rough and tasteless drupe.

If the disease is severely affected, blackberry shoots lose winter hardiness and the plants may simply not survive until the next season.

Rust

The fungus Phragmidium Link, which causes this disease, lives and hosts exclusively on blackberries.He is of little interest to other berry crops.

It has five stages of development, but it all begins in late spring, when tiny dusty brownish-yellow dots appear on the leaves and stems, which turn into large spots as they develop.

The disease, which at first seems harmless, can carry away up to 40-60% of the crop if it develops intensively.

The shoots in their lower part are brown in color with light sores colored orange in the center.

In mid-summer, when the disease develops, orange-brown pads are already clearly visible on the upper side of the leaves. Over time, they appear on the underside of the leaves. With severe damage, the leaves begin to fly off and the shoots wither.

Although rust spreads quickly in high humidity conditions, it can also attack blackberry bushes that are weakened by lack of water.

How to deal with the main fungal diseases of blackberries

Until recently, there was no alternative to chemicals for the treatment of fungal and bacterial diseases, and copper-containing preparations such as Bordeaux mixture were considered the safest means for preventing diseases. Over the past decades, the situation has changed somewhat and at the moment, to treat various blackberry ailments, fairly harmless biological preparations can be used, which are created on the basis of strains of bacteria and fungi that most effectively fight their closest relatives.

Choose for yourself which drugs to use for the prevention and treatment of the above blackberry diseases, based on their availability in your region and your own preferences.

A 1% - 3% solution of Bordeaux mixture is used in early spring to treat whole blackberry plants and water the root zone before the buds open for preventive purposes.
Trichodermin solution (100 ml per 10 liters of water) is used to spray blackberry bushes every 10-20 days from the moment the buds open, depending on the extent of the disease.
The second time after the buds open, but before flowering, the blackberries are sprayed with Oxychom or Kuproxat.
In case of signs of disease, treatment of blackberries twice a season with an interval of 3-4 weeks with solutions of Fitolavin 300 (0.2%) and Fundazol (0.2%) proves to be effective.
For treatment, you can also use chemicals such as Topaz and Topsin M (before flowering and after fruiting).
In the fall, the shoots remaining over the winter are sprayed with a 3% Farmayod solution.
If there are obvious signs of diseases that appear during the summer, in the fall and next early spring, all blackberry bushes and the ground under them are spilled from a watering can with a 5% solution of iron or copper sulfate.

Gray rot

The causative agent of the disease is the fungus Botyrtis cinerea Pers. It lives not only on blackberries, but also on many berry and fruit crops. In the soil, its spores may not lose viability for several years in a row.

Infection of blackberries with fungal spores usually occurs during the flowering period. But all organs of the blackberry are affected - both aboveground and underground, although usually the disease is most easily recognized on the fruit - light brown softened spots, and soon the entire drupe is covered with a fluffy light gray coating. The leaves may dry out, and the shoots may also become covered with brownish spots.

Comment! In cold and wet summers, massive rotting of inflorescences and fruits can be observed.

In autumn, the affected blackberry shoots become covered with black tubercles - a refuge for spores.

Berries collected from infected blackberry plants immediately spoil, cannot be stored, and cannot be eaten even after heat treatment.

To prevent infection of blackberries with gray rot, the most effective method is to tie the branches of the lower tiers to a trellis located at least 60-70 cm above the ground, and simply remove the lower fruit buds so that they do not fall below the lowest level of the trellis. When tying shoots to the trellis, distribute them not very tightly, in the form of a fan, for better air circulation.

Be sure to remove all rotting and weather-damaged berries.

Of the chemical drugs against the disease, Horus and Strobi are effective, which need to be used to treat blackberries before flowering and after the berries ripen.

Phyllosticosis (Brown spot)

This disease, depending on the specific type of pathogen, may have different symptoms. If the blackberry is attacked by the fungus Phyllosticta ruborum Sacc, then small light spots without a border will appear on the leaves.

If the damage occurred as a result of an attack by the fungus Phyllosticta fuscozanata Thum, then the spots on the leaves will be dark brown, larger in size, with a light border. Later, the leaves will additionally be covered with black dots - the fruiting bodies of the mushrooms.

If the disease is not dealt with, then the blackberry plants weaken, the leaves fall off, and one cannot count on a good harvest.

To combat phyllosticosis, you can use any of the above fungicides. As a rule, two-time treatment is enough - in spring and summer or in autumn after fruiting.

Powdery mildew

The causative agent of the disease is the fungus Sphaerotheca macularis Wall.The disease develops, as a rule, in the first half of summer and most intensively in humid conditions. Leaves, young parts of shoots and berries are affected. The main symptom is the appearance of a characteristic white-gray powdery coating.

As the disease develops, blackberries stop growing, the berries take on an ugly shape, decrease in size, and develop an unpleasant odor.

When the first symptoms of the disease appear, blackberry bushes are sprayed 3-4 times with an interval of 10-15 days with a solution of Fitosporin (5 g per 10 l of water) or Trichodermin (100 ml per 10 l of water).

Viral

Viral diseases are not found on blackberries as often as on raspberries, and they usually tolerate them quite steadfastly, but still it is not worth discounting them at all and it is advisable to have an idea about them, since they may not have the best effect on yield.

Curly

This disease is not very common and mainly affects second-year blackberry shoots. The edges of the leaves curl downwards, the underside acquires a bronze tint, and the veins become glassy and become hard. The flowers are deformed, and the fruits practically do not set.

Mosaic

The most important danger of this viral disease on blackberries is that the affected plants may not survive the winter.

It is recognized by the chaotically occurring yellow and green spots on the leaves. As the disease progresses, the leaves may become slightly deformed and the spots may become more prominent. Can be transmitted by planting material or raspberry shoot or leaf aphids.

Yellow mesh

This type of viral disease has signs of non-infectious chlorosis associated with a deficiency or excess of certain elements. The virus enters blackberries mainly from raspberry shoot aphids.

During the warm season, the entire bush is usually covered with yellow leaves, and the shoots stop growing.

Ring spot

The virus is spread by nematodes, small worms that live in the soil. As a result of this disease, blackberry leaves are slightly deformed and covered with barely noticeable yellow spots. Yellow spots are clearly visible only in spring and autumn; in summer they become invisible. Diseased blackberry plants become brittle and brittle.

Treatment methods

Since there are no reliable methods of curing viruses yet, great attention should be paid to preventive measures:

Buy only healthy seedlings from reliable nurseries
Actively control aphids, nematodes and other virus-carrying pests
Mandatory timely destruction of diseased plants
Finally, 3 times preventive treatment of blackberries with Pentafag, which has antiviral properties, every 10-12 days. (200 ml per 10 liters of water).

Bacterial diseases of blackberries: stem and root cancer

The causative agent of the disease is the bacterium Agrobacterium tumefaciens, which lives in the soil. It is capable of infecting roots and shoots, on which lumpy growths are formed, brown on the outside and light on the inside.

Shoots stop developing, leaves turn yellow, root shoots grow thin and weakened. Yields fall, shoots lose resistance to drought and frost.

Since blackberries are infected with cancer through small wounds, it is necessary to be very careful during the planting process, trying not to damage the root system.

All diseased plants must be pruned and destroyed. The remaining blackberry bushes are treated twice with a 0.5% Fitolavin solution or Pentafaga-S solution (200-400 ml per 10 liters of water).

Advice! Particularly valuable blackberry varietiesYou can try to save those affected by this disease if you carefully dig up the plants, clean them of cancerous growths, and then carefully cover the affected areas with a mixture of clay, mullein and 1% Pentafaga-S solution.

Overgrowth or witch's brooms

The disease is caused by mycoplasmas - single-celled microorganisms. Many thin and low shoots grow from the center of the bush, which practically do not develop. This virus usually affects blackberry plants that have been weakened by drought, freezing, or other stress.

Affected plants must be destroyed, and the remaining bushes must be treated after harvesting the fruits with a 1.5% Farmayod solution.

For what other reasons can blackberries get sick?

Blackberries can suffer greatly during the ripening period from high air temperatures and direct sunlight. First of all, the berries are damaged. They turn white and seem to dry out. In prolonged heat, the blackberry bushes themselves can suffer: dehydration occurs, leaves and stems are burned, weakened shoots can dry out and die.

Therefore, in hot climates, it is preferable to plant blackberries in partial shade and provide regular and abundant watering on particularly hot days.

Many gardeners are often interested in why blackberry leaves turn yellow in the spring. Of course, this could be a sign of some kind of disease (bacterial cancer, yellow reticulation), but most often non-infectious chlorosis is to blame. Yellowing of leaves is associated with a lack or excess of one of the macro or microelements, as well as with excess moisture on heavy soils.

In order to avoid this phenomenon, it is advisable to feed blackberries with a full complex of fertilizers with the maximum amount of microelements in chelated, that is, easily digestible form.

Compliance with the rules of agricultural technology is the key to healthy shrubs and a bountiful harvest.

The reasons why blackberries are affected by the diseases listed above are very similar: high humidity, dense shoots in the bushes, lack of ventilation and non-compliance with sanitary standards for caring for the bushes.

Accordingly, the best prevention of these diseases would be to carry out the following measures:

Selection of a suitable place for planting blackberries, taking into account the climatic and soil requirements for each variety. Try to choose varieties that are resistant to disease, frost and drought.
Selecting healthy planting material and planting blackberries while maintaining the required distance between bushes, usually about 2.5 meters.
Mandatory rationing of growing blackberry shoots in spring and mid-summer so that the bushes are well ventilated and are not overcrowded.
Lack of nearby raspberry and strawberry plantings, as well as thickets weed.
Trimming the lower shoots and leaves to a height of 50-80 cm, these buds are still unproductive, but there is no contact between the blackberries and the soil.
Pruning and timely burning of old shoots immediately after fruiting.
In late autumn and early spring, clearing the soil under blackberries from plant residues, loosening and mulching with humus.
Carefully inspect your blackberry bushes on a regular basis to detect signs of pests and diseases so that action can be taken early.
Tearing off damaged leaves and removing shoots with traces of diseases.
Do not allow the soil under the blackberries to become waterlogged or overdry.
Use biological agents as much as possible, including for prevention, and use chemicals as little as possible.

Conclusion

If you scrupulously follow all the requirements of agricultural technology and carefully select varieties and seedlings for planting, then problems with blackberry diseases will be minimized. And if they do arise, now you know what to do in these cases.