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If you choose the right type of pear tree for the existing climatic conditions and take care of it, you can get a rich harvest of delicious fruits. Many varieties are not picky about the environment and soil, but they are prone to a fungal disease called pear rust. In pear disease, orange spots on the leaves are the first symptom and signal to fight against this disease.
What is pear rust
Rust is recognized as one of the most common and dangerous fungal diseases that can lead to the death of a pear tree. The disease is called so because its external manifestation is very similar to metal corrosion. Orange spots with a dark center on pear leaves are the site of fungal spores formation.
In a neglected state, they move to trunks, shoots and even fruits. There is a violation in the mode of fruit ripening and crop growth. The causative agent of this disease is the pathogenic fungus Gymnosporangium sabinae.
Causes of the development of the disease and provoking factors
There are 2 main types of rust causing fungus:
- a fungus that needs one host for the entire development cycle;
- and another representative who needs 2 different plants to fully live his life.
Rust causing red spots on pear leaves is a fungal disease that develops on 2 different plants. The first host on which it parasitizes is some species of ornamental juniper. Having matured and overwintered on their first host, rust spores with the help of the wind can spread over hundreds of kilometers and, having found a second host in the form of a pear, apple, quince, hawthorn, can continue their life cycle on them.
The susceptibility to pear tree rust disease depends on many factors that must be considered when growing fruit trees. Favors the appearance of brown spots on pear leaves:
- high air humidity;
- failure to obtain the required amount of nutrients;
- nearby plantings of juniper;
- weakened immunity of trees;
- dense crown.
Several million spores mature on 1 juniper bush.
Disease development cycle
An orange fungus appears first on needles, cones, juniper branches. These parts appear yellowed and dry. Then the fungus moves to the trunk, tree shoots, forms mycelium in the form of thickenings, swellings and hibernates under the bark. In the spring, gelatinous telithospores are formed in these places. They look like conical growths. Further, during maturation, basidiospores appear.
Basidio dries up after a spring rain, breaks away from the first owner and is carried over long distances by the wind. Getting on a pear, they quickly parasitize on it.Developing on a fruit tree, the fungus causes orange spots on the leaves and enters the stage of its development in which it must return to the juniper again for later life.
Signs of illness
You can notice the first traces of the disease in the spring, when the leaves of the pear tree bloom. Small yellow spots appear on pear leaves. They gradually grow and become orange with black dots and gray stripes in the middle.
If you do not take measures to treat rust, then after about a month, yellow growths in the form of papillae appear on the underside of the pear leaves. These are the places of formation of epidiospores, which are subsequently carried by the wind to the juniper.
At the beginning of its settlement on a fruit tree, rust does not do much harm to the pear. But if you do not fight it, then it will spread throughout the plant, the leaves on the pear will be covered with rusty spots, will begin to fly off prematurely, the shoots will slow down their growth, acquire a short and thick shape. The fruits will begin to fall off immature.
Due to premature leaf fall, the tree will not receive enough photosynthetic products, its immunity will weaken, it will become less resistant to scab disease and pests. Winter hardiness will also decrease, which is why the pear may not revive after severe frosts.
What to do if pear leaves have yellow spots
When rusty spots appear on the leaves of the pear, it remains only to take specific measures to combat the fungus. For this, various methods are used, depending on the strength of the lesion by the disease. Good results are obtained by spraying with copper and sulfur-containing preparations. Mechanical work with the consequences of the disease is of great importance.
Mechanical treatment of affected trees
If rust in the form of orange spots has spread to the pear, then measures should be taken to eliminate the spores, which are the focus of infection, as much as possible. For this:
- Cut off and burn all diseased dry and orange branches and stems in the juniper area. If it is hit very badly, then cut down the tree completely and burn it.
- If possible, plant a row of dense trees that shield the planting of pears from the planting of juniper, even if they grow several kilometers away.
- Cut off the branches (5-10 cm below the lesion border) of pears with dark spots on the leaves, infected with rust. Collect fallen leaves. Burn it all. Treat the sections with 5% copper sulfate, cover the wounds with garden pitch.
- After the destruction of the affected parts of the tree, the soil around the pear must be treated with Bordeaux liquid or urea.
All tools that were used for pruning and processing diseased trees must be disinfected.
Fungicides for pear rust
Rust fungus spores die when sprayed with fungicides designed to combat this particular disease. There are many such agents that serve to treat plants from several fungal diseases at once. For example, from scab, powdery mildew, rust. If treatment with such drugs against scab is being carried out, then it is no longer necessary to treat the tree against orange spots.
Each product has its own calendar of its effective use, which must be followed, because the measures to combat pear rust in the fall are different from the spring events.
How to deal with rust on a pear with copper-containing preparations
Copper-based products have long been used in gardening to combat various fungal diseases of plants, including those with orange spots."Bordeaux liquid", "Bayleton", "Strobi", "Raek" - widely used drugs, harmless to beneficial insects and warm-blooded animals. They are often compatible with pesticides, but may not be used with all fungicides.
The treatment of fruit trees with these preparations should be carried out by the method of fine spraying for more effective use of the fungicide. In this case, there is no drainage of liquid from the leaves. She has time to act on the spores of the rust fungus.
Fighting rust on a pear of colloidal sulfur
Treatment of the affected tree with a 0.4% solution of colloidal sulfur 5 times during the entire growing season allows you to get rid of orange spots on the pear. The effectiveness of the action is due to the release of vapors. It is the vapors that kill fungal spores without penetrating into the plant.
Spraying with colloidal sulfur is carried out:
- after the buds have swollen, but before the leaves appear;
- before flowering;
- after flowering;
- during the formation of the ovary;
- after falling leaves.
Other preparations for pear rust
A high result is obtained by spraying a pear tree four times with chemical agents against pear rust - "Fitosporin-M", "Poliram", "Skor". Each of them has its own recommendations, which must be followed.
There are folk remedies for combating rust. They are effective when the disease is at an early stage of development, or they are used as preventive measures. This is a solution of wood ash, an infusion of slurry, herbs such as horsetail, marigold, mullein.
Preventive measures
In the fight against fungal rust, mandatory attention should be paid to two types of trees - juniper and pear. A constant inspection of the juniper on the site should be carried out regularly. When the first signs are found, dry branches and leaves must be immediately cut off and burned.
Preventive treatment of pears and junipers on the site before the appearance of brown spots on the leaves is the most far-sighted and effective measure. Such measures with the use of fungicides begin in the spring and are carried out at regular intervals throughout the growing season. They coincide with the scab and powdery mildew treatment:
- The first spraying of pears is carried out in the spring 2 weeks before the beginning of flowering. At this time, the basidiospores had not yet managed to settle on the pear. Fitosporin-M is recommended.
- The second processing of fruit trees is carried out after the end of flowering. This is the time for active dispersal of fungal spores. The chemicals will kill them, preventing them from spreading to the pear.
- The third preventive measure is repeated about 20 days after the second, when ovaries 3-4 cm in length have already appeared.
These actions will protect pear plantings not only from fungal rust, but also from other diseases. Preventive measures also include the timely application of fertilizers to increase the immunity and stability of the pear. During the summer, you need to periodically pour diluted wood ash under the root - 500 g per 10 liters of water.
Disease resistant varieties
Not all pear varieties react in the same way to fungal diseases, in particular to rust. There are pears that are highly susceptible to disease, they often have red spots on the leaves, and there are more resistant ones. The most resistant varieties are:
- Bere Bosc - autumn variety, moderately tolerates severe frosts. Gives a high yield under favorable conditions, resistant to fungal diseases. Fruits are large, regular, brown-golden in color.
- Summer Williams - a variety that is demanding on fertile soil and regular fertilization, has an average resistance to frost and drought. Fruits are medium in size, tied in 2-3 pieces, taste good.Disease resistant, but susceptible to insect pests.
- Curé - winter variety, frost-hardy and drought-resistant, undemanding to the condition of the soil. Under favorable conditions, it resists fungal diseases well. In a weakened state, it can get sick with scab.
- Clapp's Favorite - a summer variety, yields a harvest in late July - early August. Fruits are medium or large, beautiful, with a carmine side. It is famous for its high winter hardiness and drought resistance. When carrying out preventive spraying, it does not get sick with fungal diseases.
- Yakovlevskaya - a winter-hardy variety with a high yield. In favorable conditions, it can retain taste and marketability for 6 months. It is famous for its complex resistance to fungal diseases.
Experience shows that varieties with strong immunity and good tolerance to frosty winters are the most resistant against fungal diseases.
Conclusion
In case of pear disease, orange spots on the leaves can lead to the death of the entire crop, if you do not start to fight the spores of the rust fungus in time. But the best method to ensure healthy fruit plantings is preventive care, which includes not only regularly spraying the garden with appropriate fungicides, but also timely watering and fertilizing. Growing a healthy, rich garden is like raising children.
Thanks for the article, but more advice is needed. Is it possible to treat a young tree with urea and what% solution
Good day!
Young trees that are at least 3-4 years old can be treated with urea. And even in this case, the concentration of the solution must be reduced. The recommended dosage for the treatment of mature trees is 0.5 kg of urea per 10 liters of water. For young seedlings, it is advisable to prepare a solution at the rate of 0.3 kg per 10 liters of water.
Garden trees can be processed both in spring and autumn. Only in the autumn period, in addition to the crown and trunks of trees, it is necessary to process the soil in the near-stem circle.