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Becoming an increasingly popular crop, blackberries are confidently settling in our summer cottages. But here pests and pathogens can lie in wait for her, which may well ruin the crop, ruin the plant, or at least add trouble to the gardener. It is desirable to recognize them as early as possible in order to start the fight in time. That’s why you need to know what major diseases and pests can threaten it.
Infectious fungal diseases
It should be noted that infectious diseases, that is, those caused by bacteria, viruses or fungi, equally threaten blackberries and raspberries. If both of these related crops grow on the site, then they may have the same diseases, which means that therapeutic and preventive measures will have to be extended to all plants.
Most often, blackberries (like raspberries) are subject to fungal diseases. The spores are easily carried by the wind or on the paws of insects, overwinter on plant debris or in the upper soil level. They usually affect weakened plants with impaired immunity. It happens that the infection began, but did not fully manifest itself due to the strength and health of the plant, and the next year it will be much worse. This is one of the reasons for the obligatory destruction of fruiting shoots, they are recommended not only to be cut, but to be burned in order to prevent the disease from giving a single chance. Many modern varieties and hybrids have resistance to fungal diseases, but it does not provide one hundred percent protection, so it is better to know the most important thing about common diseases in order to try to prevent them or recognize them in time.
Septoria or white spotting can get into a clean area with planting material, and then it spreads very quickly. At the end of rainy May, round light brown spots appear on the leaves, which gradually turn white, after a while black dots appear in the middle of white spots with a brown border, they gradually merge, the entire affected surface turns brown and falls out. First, the leaves on the shoots of the second year are affected, and then on the young ones. If the process is not stopped, it will reach its maximum during fruit ripening, and all plants will suffer until autumn. The berries will rot, young leaves, twigs, shoots seem to be covered with mucus.
The stems are affected in autumn, and the symptoms may not be seen in the first year of shoot growth. Light spots appear on the lower part of the shoots, which are almost invisible on green shoots; they can be noticed on differently colored branches. They can appear near the kidneys, at the internodes, it is difficult to notice them until black dots appear, then cracks. The bark on the affected areas peels off, twists. The bush suffers, but grows: the affected buds die, and if the shoot is affected, then a short, weak branch develops from the nearest bud.
High humidity, shading, thickening of the bush – these are favorable conditions for the development of septoria. They also contribute to the emergence of another fungal disease specific to blackberries and raspberries – anthracnose.
At the end of May and at the very beginning of June, small purple spots appear on the root suckers, young replacement shoots from below, which then merge, turning into grayish and red ulcers, in the middle of which the tissue cracks. The bark around the ulcers begins to flake off. On the leaves, spots are located along the veins or edges, the affected tissue dries up and falls off. On brushes with fruits, these spots form a closed ring, the whole brush fades, not a single fruit ripens. Mature fruits develop gray ulcers.
If the disease is not stopped, then the tops of young shoots will be covered with a thick crust. Such shoots can die in winter due to severe weakness, and if they survive the cold, the crop will be minimal, since fruit buds almost did not form during the disease. And the mushroom will bear fruit – small black dots will appear on the crusts, these are its fruits. They overwinter on the affected branches, on plant debris, on weeds, and in the spring they will capture an even larger area. Therefore, the fight must begin immediately, with the appearance of the slightest signs of defeat.
Healthy bushes show resistance to such diseases, and for good growth and health they need to be fertilized on time. Therefore, experts recommend applying a complex mineral fertilizer in the spring so that per 1 sq. m obtained 9 g of nitrogen, potassium and phosphorus. In autumn or spring, you need to give blackberries humus and compost, at least 3 kg for each bush. It is necessary to monitor the cleanliness of the land around the bushes – remove the weeds in time, completely remove the leaves in the fall, burn the shoots, even if fungal infections have not been noticed. All the earth between and around the bushes should be well dug up. And in the spring, after the first loosening under the bushes, it is useful to mulch the ground with a thick layer (7 – 8 cm) of straw with manure or peat. And when buying new seedlings, you need to inspect them very carefully so as not to bring affected specimens to the site.
Another lover of blackberries is the fungus fragmidium ruby, which causes a disease known as rust. This fungus produces different types of spores at each of its five stages of development. All stages infect the plant in different ways, and spores infect it and surrounding plants more and more.
First, small light brown or orange spots appear on the leaves at the beginning of summer, spores ripen inside them, which cover the stems, leaves, petioles with a sticky mass. Then this mass dries up, over time it turns into a film, and the leaves, petioles and stems are covered with convex orange pads, in which the next spores ripen. Then the affected stems turn brown, orange ulcers appear on them. Mushroom pickers survive the winter well and continue to harvest the plant next year. Spreading further along the stems, it causes them to dry out.
In the middle of summer, new spores scatter from the orange pads on the underside of the leaf, continuing to infect blackberries. Closer to autumn, black pustules cover the leaves, these are regular spores, they settle on the fallen leaves to survive the winter, and in the spring everything repeats again, but with greater force, young strong shoots are affected.
To protect the plants, they need to be carefully examined, and at the first manifestations of infection, urgent measures should be taken to disinfect them. A good result in the fight against fungal diseases shows garlic infusion. Take 300 g of garlic, grind, pour 3 liters of water, insist for a day. Then the filtered infusion is diluted with warm water (twenty times) and the bushes are treated with it, it is advisable to do this in the afternoon. The same tool can protect against pests – ticks and aphids.
You can treat the entire ground part of the plant with milkweed infusion, you just have to rub all the shoots, leaves and stems with a small brush or brush. For this remedy, milky greens (300 g) are crushed, left for some time under the sun, then poured with a liter of water, insisted for 5 hours, filtered. This treatment must be repeated every other day. It will take no more than four treatments for the plant to fully recover.
Treatment of plants with sulfur is excellent against fungal infections. But it can be carried out if the air temperature does not fall below +18 degrees, otherwise there will be no result. For 10 liters of water, you need to take 100 or 150 g of colloidal sulfur.
For prevention in the spring, when the leaves are just blooming and in the fall after harvesting, you can spray the bushes with Bordeaux liquid. But only it should be neutral or slightly alkaline, acidic threatens to burn the leaves. You can check the prepared liquid with litmus paper – it should not appear red after contact with the liquid. Some gardeners think it’s better to use burgundy liquid because it doesn’t contain lime. To prepare it, take 10 liters of water, 100 g of copper sulfate and 50 g of soda ash. Sugar is also added to make the liquid stick to the greens. Before applying any drug, you need to make a test on one branch.
Didimella or purple spot affects leaves less than petioles, shoots, buds. First, purple-brown spots appear on the stems, then they grow, encircle the shoot with a ring. This leads to drying and fragility of the petioles, leaf fall, the buds do not develop, they turn black, and the stems can dry out if severely damaged. Flowers and berries are not affected, but the fruits grow weak, small, sour, may not ripen. This is also a fungal disease, it occurs with high humidity on too dense bushes. Prevention – the fight against thickening, the destruction of fallen leaves, cleanliness in the aisles. You can also treat it by spraying with a tincture of garlic, Bordeaux or Burgundy liquid.
Powdery mildew and botrytis, or gray rot, affect the berries. Powdery mildew covers the berries with a white coating, can affect the shoots, more precisely, the very points of growth, young leaves. Such berries cannot be eaten, all affected parts of the plant must be destroyed. Botrytis causes rotting of berries during storage. The berries affected by it cannot be eaten either, they are not suitable for processing either. It can damage shoots by settling in internodes; shoots infected with it usually freeze out in winter. Placing shoots on trellises, without thickening, with the possibility of constant ventilation, will minimize the possibility of disease. If it could not be avoided, then the means of treating and preventing all fungal diseases are the same as in the fight against rust.
Video “Viral diseases of blackberries and raspberries”
If viral diseases have come to the plantings of blackberries and raspberries, they must be fought. The expert will tell you how to proceed in this video.
Noncommunicable diseases
It is customary to call non-infectious diseases the reaction of plants to an excess or deficiency of certain micro- and macroelements, because a nutritional imbalance often causes the leaves and shoots to dry out and prevents the fruits from ripening normally.
For example, an insufficient amount of nitrogen in the soil weakens the growth of a plant, its green parts turn pale, turn yellow, leaves can fall off just in the middle of summer. Such a plant blooms weakly, the fruits grow small, may not ripen, young shoots almost do not develop. And an excess of nitrogen leads to the appearance of brown spots on the leaves, to their coagulation and premature fall.
The appearance of a dark brown border along the edge of the leaves indicates a lack of potassium. The leaves curl because parts of the leaf plate grow unevenly, they can lose their greenery, become too pale or bluish. Berries also sing unevenly, their middle may become too soft. If there is too much potassium, then the shoots grow slowly, the internodes lengthen, dark spots of dying tissues appear on the brightening leaves, the leaves fall off.
The lack of phosphorus slows down the growth of blackberry leaves, their color changes from dark green to reddish-bronze and black when dried. Leaves fall, flowering and fruit ripening are delayed and slowed down. But an excess of phosphorus causes the leaves to lighten and discolor from the middle, and along the edges they acquire a brownish border.
If there is little calcium, then young leaves grow more and more pale, and the old ones retain their healthy rich green color. Apical buds do not develop, the upper parts of young shoots often dry out, and the ovaries decompose. Too much of this element, as it were, does not allow the shoots to grow – the internodes approach each other, the leaves gather in rosettes, the leaf tissue between the veins changes color, sometimes fills with water.
With a lack of iron, leaf chlorosis occurs – the entire space of the leaf plate between the veins brightens, as if fading. At the same time, the berries dry out, shrink. Excess iron leads to similar results: young leaves become completely discolored, and the berries dry out.
A lack of magnesium stains the leaf plate between the veins in red, against which the green stripes of the veins look very elegant, then they also turn red, and the leaves fall off, starting from the lowest ones. Actually, we admire this process in autumn, but in the middle of summer it testifies to the magnesium hunger of the plant. If the leaves darken, stretch out, violating the proportions, and then curl up and fall off, then there is too much magnesium.
When a beautiful pattern appears on the upper young leaves, between the green veins the plate first turns yellow, and then turns brown, then the leaf falls, then the blackberry clearly lacks manganese. If there is too much manganese, then the sheet becomes stained, twisted, wrinkled.
Excess and deficiency of essential nutrients are equally detrimental to the growth of blackberries, it is best to try to strike the right balance. This is possible if you carefully observe all the changes that occur during the growing season, then you can notice and correct the situation in time.
Blackberry Pests
Blackberries growing in the garden can be attacked by various pests, most often insects, which can harm all parts of the plant. But this is absolutely not necessary. The gardener’s knowledge of the main enemies can help to avoid encountering blackberries with them.
In the upper layer of soil, in wet lowlands, the bear lives and breeds – a large winged insect that has perfectly adapted to dig the ground in order to lay eggs in it. Large larvae become adults only next summer, and all this time they spoil the roots of shrubs growing on the site, vegetables, root crops – everything that you can profit from. Summer residents fight with bears cruelly and ruthlessly, otherwise you can lose the entire crop and all the plants on the site. They are collected by setting traps, poisoned by placing bait with match heads in traps, and in the fall they are lured into pits with manure. All these activities are quite capable of driving out pests.
Khrushchev also pose a considerable danger to the roots, young larvae of the May beetle gnaw thin roots, and adults are able to bite the rhizomes of the stems, thereby destroying the entire bush. And they live among the roots of our plants for 5 years before turning into a chrysalis, then only after 1,5 years the beetle flies out. If the May beetles settled on the site, then you need to collect the larvae. To do this, the bush must be completely dug up, shake off all the earth from the roots on the litter, and then sift it, selecting all the larvae. Before planting the bush back, its roots and the ground in the pit are watered with a tobacco solution (10 g of tobacco dust are taken for 100 liters of water). You can dip the roots in a clay mash, adding tobacco dust to it.
Raspberry shoot aphid, raspberry nutcracker, raspberry shoot gall midge, which is also called raspberry mosquito, can damage blackberry shoots. All these pests settle on their own, lay their eggs and place their larvae in (or on) young blackberry shoots. Affected branches must be ruthlessly cut and burned, otherwise the parasites will destroy the entire plant. Treatment with tobacco or garlic infusion works well. Many gardeners treat bushes with hot water in early spring before the buds wake up. This is a very good method of struggle, but not all plants themselves are able to easily endure such a shower. If you decide to use it, then you first need to try it on a couple of shoots, then see how they perceive it, if the kidneys will suffer.
The leaves are often affected by aphids, mites and the raspberry leaf sawfly. Bushes are saved from aphids with infusions of garlic or tobacco, a more effective drug is nitrafen. From ticks, infusions of tobacco, garlic, onion peel are used, adding liquid soap to them. If the temperature has risen above +18 degrees, it can be treated with sulfur if herbal preparations have not helped. A solution of carbolic soap is also used against the leaf sawfly.
Raspberry bud dust and raspberry-strawberry weevil can destroy fruit buds, inflorescences and ovaries. They are collected mechanically, washed off with herbal preparations, in the most extreme case, you can use karbofos.
In order to prevent pests from reaching blackberries, it is necessary to monitor the cleanliness between the bushes and in the upper soil layer – remove plant debris, dig up and loosen the soil, destroy infected leaves and shoots, and mulch the ground under the bushes.
Video “Pests of blackberries and raspberries”
This video is about what blackberry diseases are and how to protect the crop and save berry bushes from pests without the use of chemicals.
