Cultural or garden blackberries not so long ago received widespread distribution in household plots in Russia. Its most common and popular varieties originate from America or Western Europe, where weather conditions are significantly different from Russian ones. In this regard, disease resistance, actively advertised in the descriptions of blackberry varieties, may be somewhat exaggerated. And since the experience of growing blackberries and combating its various ailments in our country has not yet been sufficiently accumulated, we have to mainly focus on its closest relative - raspberry.
Blackberry Disease Classification
Like most representatives of the plant kingdom, all possible diseases of the blackberry garden are divided into four main groups:
- Non-infectious - caused by various adverse weather conditions and care errors.
- Fungal - caused by fungi by microorganisms, whose spores can move in all unimaginable ways: with the help of wind, rain, pests, tools, clothing and, of course, various plant organs.
- Bacterial - caused by dangerous bacteria that live mainly in the soil.
- Viral - caused by viruses that can spread in different ways, but most often transmitted through insect pests.
In general, insect pests play a significant role in the spread of diseases on the blackberry, but for more information about blackberry pests and how to control them, see the article in another section.
Diseases caused by fungal spores are the most numerous among all that blackberries can be exposed to. In 80% of cases of problems with blackberries, it is safe to say that she was the victim of a fungal disease. The main signs of fungal diseases are spots on blackberry leaves and stems of various sizes, shapes and colors. Spores of fungal diseases penetrate blackberry tissue through lentils, stomata and wounds and scratches on the aerial parts of plants.
Septoria (White Spot)
The causative agent is the mushroom 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 precipitation and moisture, especially in thickened blackberry plantings. The first signs of Septoria appear at the very end of spring - early summer, first on last year's shoots. It is easiest to see them 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 is actively spreading 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 the shoots and leaves, developmental delay 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 among the methods of dealing with the disease is to immediately cut off and immediately burn the affected shoots with leaves. Excess fertilization with nitrogen fertilizers can contribute to the spread of the disease, so make sure that blackberry nutrition is properly organized.
- Prior to bud break, it is necessary to spray blackberry bushes with a 1% solution of Bordeaux mixture.
- As a preventive measure, spraying blackberry from 3 to 5 times per season with a solution of Fitosporin (5 g per 10 l of water) will also help.
- When the first signs of the disease are detected, the blackberry leaves and stalks should be plentifully sprayed with a solution of Alirin B and Gamayr (1 tablet of each biological product is dissolved in 1 liter of water).
The disease is spread with the help of the fungus Gloeosporium venetum Speg. Spores of fungi are found in the soil or in plant residues.
Anthracnose is also particularly active in humid and cool conditions, excessive watering can contribute to the manifestation of the disease.
All parts of the blackberry are susceptible to disease, but leaves, shoots and petioles are particularly affected. The first signs can be observed already at the very end of spring.
The leaves along the edges and along the main veins are covered with gray-purple spots of irregular shape up to 2-4 mm in size. At the bottom of the shoots of replacement and root shoots, you can see elongated purple spots with cracks in the middle. Over time, they become dirty gray with flaking bark around. Fruit twigs completely dry out and die, and if it comes to fruit, they do not ripen, shrink and fall.
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 lots of rainfall, contribute to the development of the disease.
From Didimella suffer, first of all, not the leaves, but young shoots, petioles, buds, therefore it is quite difficult to notice it in time. Leaves are not affected as much as in the case of other diseases.
First, purple spots appear on the lower and middle parts of the blackberry shoots, blurry outlines that are able to grow quickly and become dark brown. They appear mainly in the places of attachment of petioles, which are also covered with similar spots. Blackberry bark in the places of defeat is covered with cracks, buds dry out, young shoots wither, leaves, covered with dark spots with yellow edging, fall.
Flowering is very scarce, and the ovaries form a minimum amount, which, of course, affects the harvest. However, the quality of the berries leaves much to be desired - they ripen poorly, have a rough and unappetizing drupe.
If the disease is severely affected, blackberry shoots lose their winter hardiness and the plants may simply not survive until the next season.
The fungus Phragmidium Link, which causes this disease, lives and rules exclusively on blackberries. Other berry crops are of little interest to him.
It has five stages of development, but it all begins at the end of spring, when tiny dusty brownish-yellow dots appear on the leaves and stems, and as they grow, they turn into large spots.
The disease, seemingly harmless at first, is able to carry, with its intensive development, up to 40-60% of the crop.
The shoots in the lower part are colored brown with light sores, colored orange in the center.
In the middle of summer, with the development of the disease, orange-brown pads are already clearly visible on the upper side of the leaves. Over time, they appear already on the underside of the leaves. With a strong defeat the leaves begin to fly around, and shoots wither.
Although rust spreads quickly in high humidity conditions, it can affect blackberry bushes weakened by the lack of watering.
How to deal with the main fungal diseases of blackberry
Not so long ago alternatives to chemical preparations for the treatment of fungal and bacterial diseases were not and copper-containing Bordeaux-type drugs were considered the safest means to prevent diseases. Over the past decade, the situation has changed somewhat and at the moment, quite harmless biological preparations can be used to treat a variety of blackberry ailments, which are created on the basis of strains of bacteria and fungi that most effectively fight with their closest relatives.
Choose for yourself which of the drugs to use for the prevention and treatment of the above blackberry diseases, based on their presence in your area and your own preferences.
- 1% - 3% solution of the Bordeaux mixture is used in early spring to treat blackberry plants entirely and water the root zone before the budding of the buds for prophylactic purposes.
- A solution of Trichodermin (100 ml per 10 liters of water) is used to spray blackberry bushes from the time of bud break every 10–20 days, depending on the extent of the disease.
- The second time after bud break, but before flowering, the blackberry is sprayed with Oxyhom or Cuproxate.
- In the case of signs of disease, blackberry treatments show themselves effective twice a season with an interval of 3-4 weeks with Fitolavin 300 (0.2%) and Fundazole (0.2%).
- For treatment, you can also use chemical drugs such as Topaz and Topsin M (before flowering and after fruiting).
- In the fall, the remaining winter shoots are sprayed with a 3% Pharmiod solution.
- With obvious signs of diseases that appeared during the summer, in the fall and next early spring, all the blackberry bushes and the ground beneath them are shed from a watering can with a 5% solution of ferrous or copper vitriol.
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 of his disputes can not lose vitality for several years in a row.
Blackberry infection with fungal spores usually occurs during the flowering period. But all the 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 whole drupe is covered with a fluffy light gray bloom. Leaves can dry out, shoots can also be covered with brownish spots.
In the fall, the affected blackberry shoots are covered with black bumps - a refuge of spores.
The collected berries from infected blackberry plants immediately spoil, can not be stored, they can not be eaten even after heat treatment.
To prevent blackberry infection with gray rot, the most effective method is to tie up the branches of the lower tiers to the trellis, which is at least 60-70 cm above the ground, and lower fruit buds simply to be removed so that they do not fall below the lowest trellis. When garter shoots to the trellis to distribute them is not very tight, in the form of a fan, for better air flow.
Be sure to remove all decaying and weather-damaged berries.
Of the chemical drugs against the disease, Chorus and Strob are effective, with which the blackberry must be processed before flowering and after the berries ripen.
Phyllosctosis (Brown Spot)
This disease may have different symptoms depending on the specific type of pathogen. If the blackberry attacked the mushroom Phyllosticta ruborum Sacc, then the leaves will appear small bright specks without a rim.
If the defeat occurred as a result of the attack of the fungus Phyllosticta fuscozanata Thum, then the spots on the leaves will be dark brown, larger with a light border. Later, the leaves will additionally be covered with black dots - the fruit bodies of the mushrooms.
If the disease is not combated, the blackberry plants are weakening, the leaves are falling, and you cannot count on a good harvest.
To combat phyllossticosis, you can use any of the above fungicides. As a rule, two-time processing is enough - in spring and summer or in autumn after fruiting.
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 is most intense in wet conditions. Leaves, young parts of shoots and berries are affected. The main symptom is the appearance of a characteristic white-gray powdery deposit.
With the development of the disease, the blackberry stops growing, the berries take on an ugly shape, decrease in size, and an unpleasant smell appears from them.
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 diseases are not found on the blackberry as often as on raspberries, and it usually endures them quite firmly, but still it’s not worth taking them out of account and it’s advisable to have an idea about them, since they may not affect the yield in the best way.
This disease is not very common and affects mainly blackberry shoots of the second year of life. The edges of the leaves twist downward, the underside acquires a bronze tinge, and the veins glaze, become rigid. Flowers are deformed, and the fruits are practically not tied.
The main danger of this viral disease on the blackberry is that the affected plants can not survive the winter.
It is recognized by the chaotic yellow and green spots on the leaves. As the disease progresses, the leaves may become slightly deformed, and the spots become more prominent. Can be transmitted with planting material or raspberry shoots or sheet aphids.
This type of viral disease has signs of non-infectious chlorosis associated with a deficiency or excess of certain elements. On the blackberry virus enters mainly from the raspberry-sprout aphid.
During the warm season, the entire shrub is usually covered with yellow leaves, shoots stop growing.
The virus is spread by nematodes - small worms living in the soil. As a result of this disease, blackberry leaves are slightly deformed and become covered with barely visible yellow spots. Yellow spots are clearly visible only in spring and autumn, in summer they become imperceptible. Diseased blackberry plants become brittle and brittle.
Since there are no reliable methods to cure viruses, great attention should be paid to preventive measures:
- Buy only healthy seedlings in reliable nurseries.
- To actively combat aphids, nematodes, and other pests that carry viruses
- Mandatory timely destruction of diseased plants
- Finally, 3 one-time preventive blackberry treatments with Pentaphage, which has antiviral properties, every 10-12 days. (200 ml per 10 l of water).
Blackberry Bacterial Diseases: Stem and Root Cancer
The causative agent of the disease is the bacterium Agrobacterium tumefaciens, which lives in the soil. It is capable of striking the roots and shoots, on which nodular growths are formed, brown - on the outside and light - on the inside.
The shoots are suspended in development, the leaves turn yellow, the root shoots grow thin and weakened. Crops are falling, shoots lose resistance to drought and frost.
Since blackberry infection with cancer occurs through small wounds, you must be very careful about the planting process, trying not to damage the root system.
All diseased plants must be cut and destroyed. The remaining blackberry bushes are treated twice with a 0.5% solution of Fitolavin or a solution of Pentafag-C (200-400 ml per 10 liters of water).
Sprouting or witch brooms
The disease is caused by mycoplasmas - unicellular microorganisms. From the center of the bush grows a lot of thin and low shoots, which practically do not develop. Usually this virus infects blackberry plants, weakened by drought, freezing, or other stress.
The affected plants must be destroyed, and the remaining bushes must be treated after harvesting the fruit with a 1.5% solution of Pharmaiodus.
What other reasons can hurt blackberry
Blackberries can suffer greatly during the ripening of berries from high air temperatures and direct sunlight. First of all, berries are damaged. They turn white and seem to be drying out. With long-standing heat, the blackberry bushes themselves can suffer: dehydration occurs, leaf and stalk burns, 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 the blackberry leaves turn yellow in the spring. Of course, this may be a sign of some kind of disease (bacterial cancer, yellow mesh), but non-infectious chlorosis most often is to blame. Yellowing of the leaves is associated with a shortage 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 desirable to feed the blackberry with a full complex of fertilizers with the maximum amount of microelements in chelate, that is, easily digestible form.
Compliance with the rules of agricultural technology - a pledge of healthy shrubs and abundant harvest
The causes of blackberry lesions for the diseases listed above are very similar: high humidity, thickening of shoots in the bushes, lack of ventilation and failure to comply with sanitary standards for bushes care.
Accordingly, the best prevention of these diseases will be the following:
- Selection of a suitable place for planting blackberries, taking into account the climatic and soil requirements for each class. Try to choose resistant varieties of disease, frost and drought.
- Выбор здорового посадочного материала и закладка ежевичника с соблюдением необходимого расстояния между кустами, как правило, около 2,5 метров.
- Обязательное нормирование весной и в середине лета вырастающих побегов ежевики, чтобы кусты хорошо проветривались и не были загущены.
- Отсутствие поблизости посадок малины и земляники, а также зарослей сорняков.
- Pruning the lower shoots and leaves to a height of 50-80 cm, these buds are still unproductive, but there is no contact of the blackberry with the soil.
- Pruning and timely burning of old shoots immediately after fruiting.
- Cleaning in the late autumn and early spring of the ground under the blackberry from plant debris, loosening and mulching with humus.
- Careful regular inspection of blackberry bushes in order to detect signs of pests and diseases in order to take action in advance.
- Breaking off damaged leaves and removing shoots with signs of disease.
- Do not allow waterlogging and overdrying of the soil under the blackberry.
- Make the most of biological products, including for prevention, and use chemistry to a minimum.
If you scrupulously fulfill all the requirements of agricultural engineering and carefully select varieties and seedlings for planting, problems with blackberry diseases will be minimized. And if all the same arise, now you know what to do in these cases.