How to get rid of scab on a pear tree: control and prevention measures

Pear

Scab is a serious disease that can cause significant damage to crops. It's especially dangerous for pear trees. To protect your trees, it's important to understand its causes, symptoms, and treatment methods. Both modern and traditional methods of control can yield good results. As soon as the first symptoms of scab appear on your pear tree, take immediate action.

Description of pear scab with photos

Scab is a fungal disease that most often affects pear and apple trees. Venturia pirina is a highly specific pathogen. It overwinters on shoots or in previous year's foliage, and with the arrival of warmer weather, it begins to actively multiply, infecting fruit trees. If left untreated, the infection quickly spreads to healthy crops.

Causes and symptoms of the disease

Fungal spores are most active under certain conditions. These include:

high humidity of air and soil;
prolonged rains;
temperature within 20-25°C;
lack of feeding for a long time;
insufficient or poor care.

The infection primarily affects diseased trees. Such trees have weakened immune systems, making them an easy target for parasites. Excessive planting density facilitates the rapid spread of the fungus.

Attention!

The pathogen acts selectively. The fungus on pear trees does not affect apple trees, and vice versa, but it does infect other crops.

Leaves and fruits damaged by scab are unmistakable. The first symptoms of the disease are noticeable in early spring. Leaf blades become covered with yellowish spots, which eventually swell and burst. At the same time, the green foliage loses its glossy, bright green color, turning a pale olive color. If left untreated, the brown spots spread to flowers, ovaries, fruits, and shoots. Infected flowers fall off before ovaries can form. Affected fruits become deformed, cracked, and small. The flesh becomes woody, losing flavor and pear aroma. Gradually, the fungus affects the entire plant, leading to its death.

Why is scab dangerous for pears?

Primarily, fungal activity affects the quality and quantity of the harvest. A diseased pear tree produces very few fruits. The infection can destroy up to 80% of the entire harvest. Fruit with spots is unsuitable for consumption and storage. Even if the fruit has very few spots, they begin to spread to the remaining peel during storage.

The pathogen is so active that it can attack trees at any stage of development. If treatment is not provided promptly, at best, the fruit tree will not bear fruit; at worst, it will die. Furthermore, scab facilitates the spread and penetration of other infections. This combination is detrimental to the tree.

How to combat scab on a pear tree

Pear treatment should begin at the first sign of disease. This will allow for more effective and rapid elimination of the pathogen. For minor infestations, folk remedies are used. Chemical treatments are used only for severe infections.

Folk remedies

Using natural remedies is a safe way to eliminate the infection for humans, animals, and trees. You can treat pear scab with the following folk remedies:

Horsetail. The greens are steeped in boiling water for 1-2 days. The resulting mixture is applied to the tree's roots. This procedure is performed before the start of the spring season.
Mustard powder. Dissolve 100 g of mustard powder in a bucket of warm water. Spray the plants with the mixture up to four times per season.
Salt solution. Mix 1 kg of salt per 1 liter of water. Treat the pear tree with this solution in early spring, before the buds open.

Chemicals (fungicides)

There's a wide range of chemicals available for treating scab on plants. These products typically offer a comprehensive approach. Before using them, be sure to read the instructions and safety requirements for handling them.

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You can cure a pear tree using the following chemicals:

Topsin M is a fungicide belonging to the group of contact-systemic chemicals. This product is particularly effective in the early stages of the disease. It provides both therapeutic and preventative action, providing protection against fungal pathogens for a week or more.
Merpan is a contact fungicide. It effectively suppresses the pathogen regardless of cultivation zone or weather conditions. It prevents damage to both fruits and leaves.
Horus is a broad-spectrum active ingredient. It is primarily intended for the preventative treatment of plants in early spring against fungal diseases.
Tridex is a low-toxicity fungicide with a comprehensive action against the pathogen. It is widely used to combat scab on fruit trees.
Poliram DF is a broad-spectrum contact fungicide for the control of fruit tree diseases. It works effectively from the very beginning of the growing season, reliably protecting plants until the fruit begins to ripen.

Attention!

Chemical treatments are a radical way to combat scab. Uncontrolled use can weaken the pear tree's immune system and increase the fruit's nitrate levels.

It's best to spray pear trees with different chemicals throughout the season, alternating them. This will prevent the fungus from developing resistance to a particular fungicide. The final spraying should be done 3-4 weeks before harvest.

Terms and conditions of processing

Treatment of diseased pears is carried out strictly according to a schedule. Spraying is carried out taking into account weather conditions and the severity of the infection. Severe infestation requires five treatments:

during the period of formation and swelling of buds;
during bud formation;
after flowering is complete;
2 weeks after the previous treatment;
at the end of summer or beginning of autumn (autumn treatment).

During the humid season, when there is heavy rainfall, the number of treatments is increased to 6-7. During this period, it is advisable to use traditional remedies. Ideal conditions for spraying are calm, dry weather. If it rains after spraying, repeat the procedure on a sunny day.

Preventive measures

Fungal spores are known to overwinter in last year's foliage. Therefore, removing last year's foliage is a key agricultural practice. After harvesting, it must be collected and burned. The soil around the tree trunks is then dug to a depth of 30 cm. Other preventive measures include:

Pear seedlings should be planted in a well-lit area where there are no drafts and where the groundwater is at a depth of 2 m.
Maintain planting density. The closer fruit trees are planted to each other, the higher the risk of infection.
During the growing season, trees are inspected as often as possible to avoid missing the onset of disease.
The tree is pruned annually. Damaged and weakened branches are removed. A very dense crown must be thinned out.
Suspicious leaves and fruits must be removed. If the harvest is abundant, small fruits are picked from the pear tree in the fall.
Immediately after leaf fall or harvest, apply mineral fertilizers. These should contain potassium carbonate, silicon, and phosphorus. In the fall, after the leaves have fallen, treat the soil around the plantings with 7% urea or 10% ammonium nitrate.

Attention!

If brown spots appear on fruits, leaves, or young shoots, preventative measures won't save the tree. In this case, any antifungal or folk remedy can be used to combat scab on the pear tree.

Scab-resistant pear varieties

To ensure your harvest is healthy and beautiful, it's important to choose the right pear variety. Several varieties (see photos) are particularly resistant to scab. These include:

Augustovskaya Rosa. This variety is recommended for cultivation in the central and southern regions of Russia. It has gained widespread popularity due to its high resistance to many diseases and the excellent taste of its fruit.
Fragrant. The tree is short, with a medium-dense, broadly pyramidal crown. The fruits are green, with a brick-red blush, medium-sized, and pear-shaped. The skin is smooth and shiny. The variety has moderate resistance to scab.
Kudesnitsa. This variety is well suited to the southern regions of Russia. It grows quickly, requires little care, and is ideal for developing new fruit tree varieties.
Chizhovskaya. A high-yielding, widely grown variety, bred by crossing two cultivars: Olga and Lesnaya Krasavitsa. The tree is medium-sized, reaching a height of 2.5 m.
Tikhonovka. Tikhonovka trees are considered medium-sized. The fruits are versatile: they are delicious both fresh and processed. This high-yielding variety is resistant to most diseases.
In Memory of Yakovlev. The plant is characterized by rapid growth, but the height of a mature tree usually does not exceed 2 m. The fruits have a smooth or slightly ribbed surface.
Severyanka. The tree is medium-sized, with a medium-density, broadly pyramidal crown. The fruits are small, yellow with green spots. The skin is dense and dull. The flesh is creamy, juicy, and medium-firm.