Rust on a pear: how to treat yellow and rusty spots on leaves

If you choose the right variety 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 picky about the environment and soil, but they are susceptible to a fungal disease called pear rust. With pear disease, orange spots on the leaves are the first symptom and a 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 the formation of fungal spores.

In a neglected state, they pass 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 fungus that cause rust:

• a fungus that needs only one host for the entire development cycle;
• and another representative who needs 2 different plants to fully live his life.

Rust, which causes red spots on pear leaves, refers to a fungal disease that develops on 2 different plants. The first host on which it parasitizes are some types of ornamental juniper. Having matured and overwintered on its first host, rust spores can spread hundreds of kilometers with the help of the wind and, having found the 2nd host in the form of a pear, apple, quince, hawthorn, can continue its life cycle on them.

The susceptibility to rust disease of pear trees depends on many factors that need to be considered when growing fruit trees. Favors the appearance of brown spots on pear leaves:

• high humidity;
• not getting the required amount of nutrients;
• nearby plantings of juniper;
• weakened immunity of trees;
• thick crown.

On 1 juniper bush, several million spores ripen.

Disease development cycle

An orange fungus appears first on needles, cones, juniper branches. These parts look yellowed and dried out. Then the fungus moves to the trunk, shoots of the tree, forms a mycelium in the form of thickenings, swellings and hibernates under the bark. In spring, gelatinous telitospores form in these places. They look like conical outgrowths. Further, during maturation, basidiospores appear.

Basidio dry up after a spring rain, break away from the first owner and are carried by the wind over long distances. Getting on a pear, they quickly parasitize on it. Developing on a fruit tree, the fungus causes orange spots on the leaves and goes into a stage of its development in which it must again return to the juniper for later life.

Signs of the disease

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 the leaves of the pear. Gradually, they increase 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 where epidiospores are formed, which are later transferred 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 become covered with rusty spots, they will begin to fly off prematurely, the shoots will slow down their growth, take on a short and thick shape. The fruits will fall off unripe.

Due to premature leaf fall, the tree will not receive enough photosynthesis 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 be reborn after severe frosts.

What to do if there are yellow spots on pear leaves

When rusty spots appeared 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 severity of the disease. Good results are obtained by spraying with copper- and sulfur-containing preparations. Mechanical work with the consequences of the disease is important.

Mechanical treatment of affected trees

If rust in the form of orange spots has spread on a pear, then measures must be taken to maximize the destruction of spores, which are the focus of infection. For this:

1. Trim and burn all diseased dry and orange branches and stems located on the juniper site. If he is hit very hard, then cut down the tree completely and burn it.
2. If possible, plant a row of dense trees that protect pear plantations from juniper plantations, even if they grow several kilometers away.
3. Cut branches (5-10 cm below the border of the lesion) of pears with dark spots on the leaves, infected with rust. Collect fallen leaves. Burn it all. Treat the sections with 5% copper sulphate, cover the wounds with garden pitch.
4. The soil around the pear after the destruction of the affected parts of the tree must be treated with Bordeaux liquid or urea.

All tools that were used to trim and treat diseased trees must be disinfected.

Pear Rust Fungicides

Rust fungus spores are killed when sprayed with fungicides designed specifically to combat this disease. There are many such remedies that serve to treat plants from several fungal diseases at once. For example, from scab, powdery mildew, rust. If such anti-scab preparations are being treated, then it is no longer necessary to treat the tree against orange spots.

Each tool 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 measures.

How to deal with rust on a pear with copper-containing preparations

Copper-based products have long been used in horticulture to combat various fungal plant diseases, including orange spots. “Bordeaux liquid”, “Bayleton”, “Strobi”, “Raek” are widely used drugs that are harmless to beneficial insects and warm-blooded. They are often compatible with pesticides, but may not be suitable for all fungicides.

The treatment of fruit trees with these preparations should be carried out by fine spraying for more efficient use of the fungicide. In this case, there is no runoff of liquid from the leaves. She manages to influence the spores of the rust fungus.

Fighting rust on a pear with 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 inside the plant.

Spraying with colloidal sulfur is carried out:

• after swelling of the buds, but before the appearance of leaves;
• before flowering;
• after flowering;
• during the formation of the ovary;
• after November

Other preparations for pear rust

A high result is obtained by spraying the pear tree four times with chemical agents for pear rust – “Fitosporin-M”, “Polyram”, “Skor”. Each of them has its own recommendations, which must be followed.

There are folk remedies for rust control. They are effective when the disease is at the initial 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 permanent inspection of the juniper on the site should be carried out regularly. Upon detection of the first signs, dry branches and leaves should be immediately cut and burned.

Preventive treatment of pear and juniper 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 treatment for scab and powdery mildew:

1. The first time pear spraying is carried out in the spring 2 weeks before flowering. At this time, the basidiospores had not yet had time to settle on the pear. “Fitosporin-M” is recommended.
2. 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.
3. The third preventive measure is repeated approximately 20 days after the second, when ovaries 3-4 cm long 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.

Varieties resistant to disease

Not all varieties of pears react equally to fungal diseases, in particular to rust. There are pears that are highly susceptible to the disease, they often have red spots on the leaves, but there are more resistant ones. The most resistant varieties are:

1. Bere Bosk – autumn variety, moderately tolerates severe frosts. Gives a high yield under favorable conditions, resistant to fungal diseases. The fruits are large, regular shape, brown-golden color.
2. Summer Williams – a variety demanding on fertile soil and regular fertilization, has an average resistance to frost and drought. Medium-sized fruits, tied in 2-3 pieces, have a pleasant taste. Resistant to diseases, but susceptible to attack by insect pests.
3. Cure – winter variety, frost-resistant and drought-resistant, undemanding to the state of the soil. Under favorable conditions, it resists fungal diseases well. In a weakened state, it can get sick with scab.
4. Clapp’s favorite – summer variety, yields in late July – early August. The 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 suffer from fungal diseases.
5. Yakovlevskaya – winter-hardy variety with high yield. In favorable conditions, it can retain taste and commercial qualities 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

With pear disease, orange spots on the leaves can lead to the death of the entire crop if you do not start fighting rust fungus spores in time. But the best method for ensuring healthy fruit plantings is preventive care, which includes not only regular spraying of the garden with appropriate fungicides, but also timely watering and top dressing with fertilizers. Growing a healthy rich garden is like raising children.