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Raspberry leaves turn yellow – such a problem can appear not only in the middle of summer or closer to autumn, but also in spring. It is provoked by shrub diseases and pests, as well as improper care of the plant.
Why do raspberries have yellow leaves?
Raspberries on the site turn yellow in spring and early summer for several reasons. To determine what caused the problem, you need to carefully examine the bush and evaluate the quality of agricultural technology.
Lack of nutrients
Raspberries are not particularly capricious. But on poor soils and in the absence of top dressing, the shrub begins to bear fruit worse, and sometimes turns yellow and sheds leaves. You can understand which element the plant lacks by its appearance:
- If the development of the shrub has slowed down, and the crown has brightened and faded, this indicates a nitrogen deficiency.
- If the raspberries turn yellow, but bright streaks remain on the leaves, we are talking about a lack of iron.
- If the plates first changed color, began to curl around the edges, and then dried up and began to fall off, then there is not enough magnesium in the soil.
- If gray-yellow spots appear on the leaves, and then the greens begin to crumble, there is a zinc deficiency.
- If the raspberry plates are covered with light yellow stripes and stains, darken at the edges and begin to die, the bushes lack calcium.
You can talk about nutrient deficiency if the plant turns yellow, but there are no traces of pests and fungal diseases on the leaves. To cope with the lack of trace elements, it is necessary to apply complex fertilizers or feed raspberries with a specific substance.
Raspberry diseases
Raspberries rarely suffer from a critical lack of nutrients. Much more often, its crown turns yellow due to fungal and viral diseases, many of which begin to harm the shrub in early spring.
infectious chlorosis
If raspberries have yellow leaves with green veins, then we are usually talking about infectious chlorosis, or jaundice. The disease manifests itself in much the same way as iron deficiency, but it is caused by a virus, and not by violations of agricultural technology. Raspberries turn yellow from the upper leaves to the lower ones, at first the vessels still remain green on the plates, but then they lose their color.
The stalks, sepals and petioles also acquire a golden hue, young shoots weaken and stretch. Under the influence of infectious chlorosis, raspberries not only turn yellow, but also give less juicy, small berries, and eventually degenerate.
Raspberry infectious chlorosis is not treatable, the diseased shrub must be dug up and burned
ring spot
Viral disease manifests itself as pale yellow or light green ring-shaped patterns on raspberry leaves. Symptoms develop in late spring or early summer, may disappear by August, but then return again. Raspberries turn yellow, slow down development, their shoots become brittle and short, and the berries dry out quickly.
Ring spot prevention is the use of healthy seedlings and varieties with strong immunity. There is no cure for the disease, the affected raspberries are simply destroyed.
Raspberry ring spot is often carried by a nematode
Mosaic
Against the background of a viral disease, raspberries turn yellow in early summer, its leaves are deformed and become bumpy. The root shoots gradually degenerate and become thinner, the berries lose their juiciness and softness.
Mosaic rarely provokes the death of raspberries, but impairs fruiting. It is impossible to cure the disease, infected specimens are destroyed. Attention should be paid to prevention – pruning, tillage and spraying against aphids.
Mosaic-affected raspberries tolerate cold snaps worse
Rust
Fungal disease most often passes to raspberries from sedge or coniferous trees in warm and humid weather. In the second half of spring, the leaves on the inside are covered with small tuberous reddish-brown spots. The outer surface of the plates turns yellow. Over time, the spots grow and occupy the entire leaf entirely. Raspberry plates dry from the edges to the middle and crumble.
You can cope with rust by spraying with XOM and Topaz preparations. The treatment is carried out twice with an interval of three weeks. For prevention, you can spray raspberries with copper sulfate or Bordeaux liquid even before bud break.
Against the background of rust, raspberries turn yellow, lose frost resistance and bring small, tasteless fruits.
Root cancer
Raspberry root cancer develops on alkaline soils in dry climates. Most often it affects shrubs with open damage to underground rods. Galls, or small outgrowths, are formed on the roots, at first soft, and then becoming woody, sometimes they extend to the neck of the stem. Raspberries, under the influence of the disease, cease to receive a sufficient amount of moisture and nutrients, turn yellow, develop worse and eventually die.
It is impossible to cure root cancer, so the bush is simply destroyed. After that, the soil on the site is treated with copper sulphate and other plants are not planted to replace the eliminated one for three years.
Prevention of cancer is the treatment of the roots of seedlings with copper sulphate
Fitoftoroz
Late blight fungus also affects the roots of raspberries and for a long time practically does not make itself felt. But as the disease develops, the plant turns yellow and begins to drop leaves, and then completely dies. The most active pathogen of the fungus acts in wet weather at a temperature of about 20 ° C. The disease can be recognized not only by a change in the color of the raspberry leaves, but also by the drying of the side shoots, as well as by the darkening of the core of the buds.
Fungicidal agents have almost no effect on the causative agent of late blight, so severely affected bushes are simply eliminated. If the raspberry turns yellow slightly and looks relatively healthy, you can shed the soil around it with copper sulfate.
To prevent late blight, raspberry seedlings should be carefully treated with fungicides even before planting.
Curly
Viral curl of raspberry leaves leads to deformation of the shrub plates. They shrink and wrap inward, the underside turns yellow or turns brown. Ripening raspberries become smaller, become dry and sour.
It is impossible to cure curliness, so the affected plants are removed from the site and burned. For prevention, it is necessary to spray raspberries with Bordeaux liquid from early spring and treat the roots of seedlings with a solution of potassium permanganate before planting.
Curly can completely destroy a raspberry bush in just a few days.
Pests of raspberry
The leaves of remontant raspberries turn yellow not only under the influence of diseases, but also when infected with pests. Indirect signs of the presence of insects are holes and other damage on the plates of the bush.
aphid
The garden pest has a small size, but at the same time forms very large colonies. Raspberries can be affected by green, gray and black aphids, the latter varieties are easier to notice on the leaves of the shrub. Insects suck juice from young plates, as a result, the plant turns yellow and fades.
You can get rid of aphids with a home solution – in a bucket of water, you need to dilute 1 kg of wood powder and a crushed bar of laundry soap. Wormwood or onion infusions also help. Raspberry treatments with Karbofos and similar insecticides give a good effect.
An additional danger of aphids is that the insect carries raspberry viral diseases.
spider mite
The spider mite infects raspberries in warm and dry weather with a lack of moisture. You can find an insect on the underside of the leaves, usually the pest has a red, brown or yellowish body. The presence of a tick is evidenced by a thin web on the shoots of a shrub.
Under the influence of the pest, raspberries turn yellow, its foliage curls and fades. To combat the tick, insecticidal preparations of general action are used, as well as garlic infusion or a solution of wood ash.
Simple spraying of raspberries along the crown helps to prevent the appearance of a spider mite.
Improper care
Raspberries turn yellow with improper agricultural practices. In particular, fungi and pests are especially likely to infect thickened plants. If you do not thin out the shoots, then the access of fresh air deep into the bushes will inevitably worsen, moisture will stagnate on the leaves. It is necessary to carry out a sanitary haircut for raspberries annually. In the process, not only dry branches should be removed, but also root shoots, as well as crooked shoots growing inside the bush.
Raspberries often turn yellow due to excess moisture. If the weather is rainy, then additional watering of the shrub is not necessary. It is better to pay attention to the periodic loosening of the soil – this will prevent its acidification and the formation of a hard crust.
After prolonged rains, washing out nutrients from the soil, raspberries especially need to be fed.
Lack of moisture
Raspberries turn yellow not only when waterlogged, but also against the background of drought. In hot summer periods, it is necessary to water the plant weekly, each time bringing 10-30 liters of water under the bush. To make moisture evaporate more slowly, it is recommended to mulch the soil with sawdust, straw or wood chips.
Increased soil acidity
Raspberries turn yellow on the leaf in soils with excess nitrogen. If the soil on which the shrub grows is too acidic in composition, it is necessary to add 1 kg of wood ash or dry alkali per 1 m2. After that, the ground under the raspberries is carefully dug up. This treatment helps to bring the acidity level of the soil closer to neutral.
What to do if the raspberry turned yellow
At the first signs of yellowing of raspberries, it is necessary to carefully examine the foliage and shoots of the shrub. If spots, dots, plaque or holes are noticeable on the plates, unusual patterns and deformations are present, then most likely the discoloration is caused by pests or fungi. It is necessary to carry out several treatments with copper-containing preparations or insecticides, observing intervals of 2-3 weeks.
If spraying does not work, and the raspberry still turns yellow, care should be reconsidered. Extra fertilizing is introduced into the soil, watering is normalized – the soil should not dry out, but waterlogging should not be allowed. If necessary, pruning is carried out for the shrub, and as a last resort, the plant is dug up and transplanted, along the way inspecting the roots for damage.
Remontant raspberries require top dressing more often than usual, as they consume nutrients more actively
Prevention
General rules of prevention help prevent yellowing of raspberries. They reduce the likelihood of fungal development and make the shrub more resistant to pests. In particular, it is necessary:
- choose healthy seedlings without damage and disinfect their roots in a weak solution of potassium permanganate;
- spill the soil in the garden before planting raspberries with fungicides;
- prevent drying or waterlogging of the soil;
- apply complex top dressing for raspberries three times a season;
- regularly carry out sanitary and formative pruning;
- promptly remove the root shoots of the shrub.
When growing raspberries, it is important to keep the area clean. With the onset of autumn, it is necessary to remove all plant debris, since fungal spores and pest larvae usually overwinter in it.
Conclusion
Raspberry leaves turn yellow – this problem appears most often against the background of fungal diseases and improper care. Sometimes a change in the color of the plates is provoked by harmful insects. With yellowing, it is important to immediately start treating raspberries, since in the later stages it is much more difficult to solve the problem.
