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How to treat raspberries

Photo of treating raspberries for diseases and pests

Any gardener would be upset to see the leaves of a once thriving raspberry (we're talking about cultivated raspberries) becoming diseased. Many factors — such as nutrient deficiencies, water shortages or diseases — lead to leaf damage. Once you determine the cause of the problem, you can return your raspberries to peak yield with a few simple fixes. Although this is not always possible. But in any case, you need to know how to provide proper care for raspberry leaves, whether they are healthy or sick.

If you don't provide your raspberries with enough water, they will soon show signs of drought stress. It is manifested by the following signs:

  • Wrinkled leaves;
  • Wrinkled fruits;
  • Dry, stringy shoots and roots.
All of these signs are clear evidence that your raspberry plants are not getting enough water. After bushes with these symptoms are given the proper amount of water, damaged leaves are removed, and the plants should recover. At the same time, avoid overhead watering, because water remaining on the leaves can cause disease, primarily sunburn.

Various diseases cause leaf damage. Infected plants should be removed and destroyed immediately upon discovery to prevent the spread of the contagious disease.

Verticillium wilt is one of the fungal diseases that causes the leaves to change color to yellow and brown, as well as the darkening and rapid death of the entire shoot. The causative agent of Verticillium wilt lives in the soil for many years, so it is very important to remove and destroy the affected plants, and the next raspberry plantation should be moved to a new area, away from the infected one. The minimum distance is 15 meters.

Raspberry mosaic disease causes leaves to become mottled, yellow-green with brown tips, and results in the growth of gnarled shoots. This is a viral disease transmitted by garden pests, and mosaic disease cannot in principle be cured. Infection can be prevented by planting varieties that are resistant to the disease. It is also necessary to combat aphid populations by regularly spraying raspberry plants with a strong stream of water early in the morning to knock off (wash away) pests from the plants - these are the only real ways to combat viral mosaic.

How to treat raspberries if the leaves curl

Abnormally bent and curled raspberry leaves are an early sign that your plants are infected with a deadly disease. Leaf curl is a viral and incurable disease carried by the small crimson aphid. Leaves will change, sometimes dramatically, in the early stages of infection. Often they appear to be stretched over an arch, or curl down and change color. Red raspberries typically develop yellow leaves, while black raspberries' foliage becomes abnormally dark — green in color, with a seemingly greasy surface. As the disease progresses, the shoots become as if frozen, they seem to freeze and become fragile, and the fruits ripen small, frayed and crumbly, which makes them practically inedible.

If the leaves on the raspberries in your garden have already curled and there are other signs of leaf curl disease, you need to remove and burn the infected plants as soon as possible. There is no answer to the question of how to treat raspberries if the leaves curl. There is simply no cure for this disease, but by removing infected plants you can keep clean bushes nearby. Make sure you clean working tools (shovels and pruners) well after removing affected shoots to prevent the virus from being transferred from infected plants to your clean stock.

How to get rid of rust on raspberry leaves

The leaves of this disease are affected by a fungus. Yellow-orange pustules are visible on the underside of the leaves, premature death of foliage, and increased frost damage to shoots on an infected plantation are observed. The disease is not systemic and will not spread throughout the entire plantation, but the fungal spores are carried by the wind. Small yellow spots appear on the surface of the leaves of infected plants in the spring. If left untreated, yellow rust can spread from plant to plant, causing abnormal leaf loss and poor fruit production.

To prevent this fungal disease, you need to grow raspberries only in areas with good soil drainage and good air circulation. You need to weed well around the raspberries, keeping the ground free of excess vegetation. As for how to properly care for raspberry leaves, you need to regularly clear fallen leaves, branches and debris from the ground with a rake in order to promptly remove materials that are contaminated with fungal spores. All cut down weeds and other removed materials should be collected in a trash bin and taken away from the raspberry plantation.

Spraying raspberry plants with fungicide solutions in the spring is good as a preventative measure. Fungicide should be applied to raspberry bushes twice a week during rainy periods and every 7 — 10 days during dry periods. Fungicide use is effective for treating small outbreaks of yellow rust until mid-July. This is the main thing you need to know for those who are interested in how to get rid of rust on raspberry leaves.

How to deal with drying out of raspberry leaves

If raspberry leaves dry out and shoots wilt and break on their own at ground level, first check to see if your raspberry plants have received enough water, as this is the main cause of wilting in water-loving raspberries.

If your plantation is adequately watered, then raspberry gall midge may be the culprit of your problems, and you need to know how to deal with drying out of raspberry leaves caused by gall midge larvae. This is a small brown mosquito no larger than 2 mm in size that lays its eggs under the bark of shoots. The larvae gnaw out small cavities in young shoots, but can also penetrate into the roots. This defeat causes the shoots to wither with the leaves drying out, spindle-shaped canes appear, which usually come off at or below ground level. Check for larvae inside shoots or galls (swells) in areas below the soil surface. It is best to remove and burn or at least throw away the infected canes away from the area.

Drying of leaves can also begin due to a deficiency or excess of nutrients. In order to determine which nutrients the plant is lacking, you need to test the soil using a home test kit. Although fertilizing can correct nutrient deficiencies, raspberry leaves may again begin to dry out if the plants have been over-fertilized.

Yellow raspberry leaves

The symptoms are — a yellow color appears, evenly distributed over the leaf surface with a very small percentage of spotting. Yellowing tends to follow the variegation pattern and the light spotting may be quite limited on the leaf. Affected leaves eventually separate easily from the main plant. Yellowing and dieback most often occurs on the lower half of the plant, rarely reaching higher levels, and does not result in complete plant death. Yellowing usually does not result in any reduction in vigor or yield of the plant, but there are cases of complete plant loss. In some cases, there is a selective loss of integrity and crumbling of the fruit in the affected areas of the shoot, but this is an extremely episodic phenomenon.

Most often, yellow raspberry leaves appear due to a deficiency or excess of nutrients. Typically, nitrate, sodium, and chloride concentrations are very low in soil where leaf yellowing occurs. Nitrogen and phosphorus levels are also below adequate levels and significantly lower in yellow leaves than in normal green leaves. At the same time, the level of calcium in yellow leaves is higher than sufficient, and significantly higher than normal compared to the leaves of healthy green plants.

Knowing basic information about the disease, you can provide your plantation with normal care for black raspberries and its leaves, which will prevent the spread of many diseases. And in order to have fewer problems with this, purchase planting material that is absolutely free from diseases and pests, which is grown in nurseries.