Despite the fact that many modern raspberry varieties are resistant to various diseases, damage to individual bushes or whole raspberries still happen. Therefore, it is very important to know the main ways to combat the most common diseases of raspberry.
When processing fruit bushes, and in particular raspberries, from pests and diseases, maximum attention should be paid to preventive measures. Because in all cases it is easier to prevent the disease than to treat it later. What diseases cause the greatest problems and require the maximum participation of gardeners?
The causative agent of verticillus, or wilt, is the form of the fungus Verticillium albo-atrum Rein et Berth. This is one of the most deadly diseases of raspberry, because it affects the whole plant, and the bush quickly fades and dies. The virus penetrates wounds and mechanical damage. Gradually, in the affected plants, the tops of the shoots begin to fade, the leaves dry out (first at the very ground, and then higher up the trunk). Dark-purple and gray spots appear on the bark, merging into strips. The bark cracks, shoots and roots completely die off, the tops of the shoots fade, dry out and fall off.
Rapid wilting is associated with damage and blockage of blood vessels and, as a result, lack of water in the aerial parts of plants. In hot and dry summer, symptoms appear more acutely, and it seems that the plant has simply dried out. Unfortunately, varieties of cherries that are 100% resistant to verticillosis have not yet been bred, so virtually every plant is at risk.
Measures to combat verticillary wilting:
This disease is caused by fungi of the genus. Phytophthora, for a long time develops unnoticed by the observer. Most often it is associated with heavy soils and poor drainage. In wet areas, the roots are quickly exposed to the fungus and stop giving the plant the necessary vitality. The bush begins to wither and fade. The leaves turn yellow, turn red and start to dry out. Subsequently, shoots die and dry, and then the bush itself.
You should carefully examine the root system of raspberries. Dig the plant and scrape the epidermis from the upper layer and the root collar. The fabric should be snow white. On infected roots, the tissue acquires a brick-red hue. Plants affected by the blight do not form new shoots, in contrast to those damaged by cold. Spores overwinter in the ground and upon the occurrence of suitable conditions (high temperature and humidity) begin to infiltrate the roots. The stagnation of water at the roots allows disputes to actively develop, depriving the plant of forces. Unfortunately, there is no absolute “medicine” against phytophthora of raspberries, as well as varieties with 100% resistance to this disease.
Measures to combat root rot (phytophthora) raspberries:
Raspberry Curl (Leaf curl of raspberry)
This insidious disease, also called the “witch's broom,” causes fungus Rubus virus 3Inexperienced gardeners, especially those who have planted a new variety, may not even be aware of the infection. Stalks of "curly" raspberries become stocky, thickened and dense. The leaves shrivel, become small and brittle, and a bronze sheen appears on the underside. The berries dry out, become acidic, and the hands become shriveled and shallow. Raspberries, affected by curly, completely dies after 4 years.
It is very easy to transfer a virus from one plant to another: it is enough to use the same tool when pruning infected and healthy plants. Often, pathogens are introduced into the soil with root shoots (planting material) or when grafting infected cuttings. A vector of the fungus are also aphids and mites.
Measures to combat curly raspberries:
Raspberry Mosaic (Raspberry mosaic)
This is a group of the most controversial viral diseases that cause chlorotic spots and stripes on the leaves. The virus actively spreads aphids, and pathogens are introduced into the plant through wounds left by insect pests or tools, as well as through root growth.
Given that the mosaic is caused by a large number of pathogen viruses, the external symptoms of its effect on shrubs of different varieties are sometimes not similar to each other. As a rule, the leaves become variegated, with alternating light and dark areas, which are bordered by thin and thick veins. Sometimes they form patterns and fir-trees or mosaic (hence the name of the disease). The spots are usually light yellow. With a strong defeat, bulging areas appear on them, and the leaves become thinner and wither.
Sometimes in summer, the external manifestations of the disease weaken, but by the end of the growing season they are activated with a new force. Sick plants become dwarf, shoots become thinner, berries become smaller and lose taste. After a harsh winter or hot summer, the yield of raspberries is reduced by 50%, and the bushes may die completely.
Measures to combat raspberry mosaic:
Dangerous and "bright" disease causes fungus Phragmidium rubiidaei, which lives everywhere and is especially active in areas with high humidity. The signs of its appearance are small, round, slightly convex yellowish-orange pads on the upper side of the leaves. They can also be found on the petioles and central veins. On the annual shoots, gray ulcers with a reddish border are formed, which, as the disease progresses, merge into lines and cracks.
The fungus overwinters in the form of spores in the fallen leaves. In the spring, spores fall onto raspberry leaves, forming "pouches" on their underside. During the summer, several generations of spores are formed at high temperatures and humidity. A massive defeat of plants occurs by the middle of summer, and by the end of the season on the leaves you can already see whole clusters of spores, which are located for the winter. The leaves dry up, which deprives the bushes of raspberry winter-hardiness, they cannot stand the cold and long winter and soon die.
Raspberry rust control measures:
Raspberry chlorosis (Raspberry vein chlorosis)
Occine Raspberry Chlorosis Causes Virus Raspberry vein chlorosis. Sometimes the symptoms of the disease are difficult to distinguish from non-viral yellowing of the leaves, caused by a lack of trace elements or adverse weather conditions. The main distinguishing feature of chlorosis is that the leaves begin to turn yellow along the veins (which initially remain green), and then the whole leaf becomes brown in autumn. Shoots are stretched and thinned, and the berries often ripen only from the sunny side and dry out without ripening.
The active carriers of the chlorosis virus are aphids and mites. Infection occurs also during the inoculation of a diseased plant on a healthy one and upon ingestion of the juice of diseased cultures or the use of a non-disinfected instrument. Rapidly developing, the disease affects all the leaves, which eventually fall off and cease to protect the raspberry bush during the cold period. The plant weakens and dies.
Measures to combat raspberry chlorosis:
Use a healthy planting material, comply with agricultural practices and timely remove damaged raspberry shoots. Even these three simple tips will help you cope with most garden problems and get high yields.