Contents
Getting high yields is impossible without measures aimed at the prevention and control of pests and diseases. To do this, you need to know what they are, when and how they reproduce, which parts of the plant affect, the factors that contribute to their spread. Pear diseases and pests are usually closely related to one or another phase of tree development. Protective measures should be tied to them, and not guided by a calendar.
Fungal diseases of pear and methods of struggle
Fungal infections account for about 80% of fruit tree diseases. The causative agents are living organisms that reproduce by spores – fungi that feed on the mycelium, threads penetrating plant tissue.
They are transmitted from infected pears to healthy ones by insects, wind, raindrops, through contaminated tools or the hands of owners or gardeners. Contribute to the spread of fungal diseases punctures and damage made by pests, frost holes, sunburn, uncovered wound surfaces left after pear pruning.
Fungal spores hide in the soil, cracks in the bark, under plant debris. With primary infection, the disease cannot be seen with the naked eye. Subsequently, the main sign of the pear colonization with fungal spores is the covering of the leaves with spots, and after a while – their shedding.
brown spot
This disease most commonly affects the leaves, young branches, and fruit of pears in southern nurseries or orchards. It manifests itself:
- the formation of rounded brown spots on the leaves;
- small dark brown elliptical depressed spots appear on diseased pear shoots;
- fruits are covered with round carmine marks.
Over time, the leaves fall on the pear, the fruits become blistered and crack. The disease begins to manifest itself in late May or early June, reaches a peak by July-August.
The mycelium of the fungus overwinters in young shoots and on fallen leaves. The disease is favored by warm damp weather and heavy soils.
This is a common disease, it is impossible to get rid of it without 2-3 preventive spring treatments of pears from pests and diseases with copper-containing preparations or colloidal sulfur. The first is carried out along the green cone, the next – after 10-14 days.
Pear moniliosis
All fruit crops are affected by fruit rot or moniliosis. This is a disease of inflorescences, branches and young shoots, but most of all the spores are found on fruits. On the surface of the pears, grayish or yellowish pads with spores appear scattered or forming characteristic circles.
If measures are not taken in a timely manner, within a week the disease can cover the entire fetus, which eventually dries out and mummifies. Most infected pears fall off, but some can hang on a tree for up to two years, constantly remaining a focus of the disease. During storage, the fruits may become glossy and blacken.
At the beginning of the season, moniliosis affects flowers and leaves – they dry out, but do not crumble, sometimes in wet weather, grayish pads with fungal spores appear on the surface. When the disease affects the branches, the bark cracks, turns brown, and shrivels. The tops of young shoots sometimes dry out.
Mushroom spores overwinter on mummified pears, fallen diseased flowers and leaves, and plant debris not harvested in autumn. They begin life at temperatures from 2-3 ° to 32-35 ° C in rainy weather, but if the fruits are damaged by insects, the presence of moisture is not necessary. New conidia appear throughout the summer and cause secondary infection.
The development of the disease can be caused by dirty hands or tools, and any mechanical damage to the fruit, including insects, contributes.
It is impossible to cure fruit rot if all mummified pears and affected branches are not removed from the tree. To prevent the disease, it is necessary to carry out anti-aging and sanitary pruning, remove plant debris, especially carrion.
Pears are processed:
- after leaf fall in autumn and before bud swelling in spring, 4-5% calcium polysulfide (lime-sulfur decoction);
- immediately before flowering (along the white cone) and after it – 1% Bordeaux liquid.
Milky luster
There are two types of the disease:
- false milky shine caused by frostbite of a pear and of a non-parasitic nature;
- a real milky sheen caused by infection with a fungal disease.
All fruit trees are affected, more often in cold regions with severe winters. External signs of non-parasitic, caused by frostbite, and fungal (often accompanied by damage from low temperatures) pear leaf diseases are similar.
In both cases, the vegetative organs change color to light gray, with a milky tinge. In leaves affected by a fungal disease, this color is due to the penetration of mycelium into the tissue. If you cut an infected branch, the wood will turn brown. By autumn, the fruiting bodies of the fungus are formed, similar to leathery growths up to 3 cm in size and attached to diseased branches.
The spores matured in the fruiting bodies of fungi are sown twice – at the beginning and end of the vegetative season, and cause the re-development of the disease. Infected with a milky sheen, pear leaves become smaller and dry out.
Cold winters, insufficient preparation of the tree for winter, and a lack of nutrients contribute to the emergence and development of the disease.
The fungus that causes a milky sheen on a pear is considered relatively harmless. But its treatment involves the removal of the affected branches, in which it is necessary to capture 15 cm of healthy tissue. If you do not pay attention to the disease, the whole tree may die in a few years.
Mučnistaâ rosa
Pear often suffers from powdery mildew infection, the disease manifests itself as a white coating on flowers, leaves and young shoots. By the middle of summer, the plaque grows, turns gray and resembles felt. Fruit growth slows down, they crack and rust.
The fungus overwinters in buds and branches, rarely in fallen leaves. The spores are dispersed in the spring when the buds open and during the first warm rains. Cool rainy weather favors the development of the disease.
It is necessary to fight powdery mildew by carrying out standard sanitary measures and repeated spraying of the disease with foundationazole or calcium polysulfide (it is better to alternate the preparations):
- I – at the beginning of the opening of leaf buds;
- II – when opening flower buds;
- III – after falling petals.
With a strong development of the disease, 2 more treatments should be done with an interval of 2 weeks.
destroyed
If on a pear the leaves darkened and became stained with an olive coating, and clearly defined, cracked areas of the same color appeared on the fruits, the tree fell ill with scab. Shoots are rarely affected by this fungus. Scab reduces the quality and quantity of the crop, pears lose their marketable appearance, deform, and become woody in the affected areas.
The fungus overwinters in fallen leaves. Spores germinate at temperatures from 0 to 30 ° C. Primary infection in most cases occurs immediately after flowering, in summer – secondary. Young growing organs are especially susceptible to infection. The development of the disease requires high humidity.
To prevent the development and occurrence of the disease, plant debris is removed from the site in the fall. Spraying with 1% Bordeaux mixture or other copper-containing preparation is carried out at least 4 times:
- with the isolation of flower buds;
- on a pink cone (opening of flower buds);
- when the petals fall;
- 2 weeks after flowering.
Severe infestations or no treatments in previous years may require additional sprays.
Blue scab spray
Instead of multiple treatments in the spring and summer of pear scab, you can do one at the very beginning of the season. As soon as the flower buds swell, the tree is sprayed with 4-6% Bordeaux mixture. It is impossible to delay this procedure – a copper-containing drug in high concentration can destroy the crop rather than the disease.
If the spring was rainy, after 30-45 days, a control treatment of the pear with 1% Bordeaux mixture is carried out.
Rust on pear leaves
Pear trees do not infect each other with rust. An indispensable condition for the occurrence of this fungal disease is the proximity of juniper. A sign of infection is the appearance of burgundy spots on the leaves of the pear with an orange edging above, below – yellow or orange pads with spores. Swollen spots form on shoots and fruits.
In the spring, before the buds open and after the petals fall, the pear is treated with a copper-containing preparation, and after leaf fall – with a concentrated (0,7 kg per 10 l) solution of urea.
Sooty fungus
It is correct to call this disease black, and not sooty fungus. It appears as a black, easily washable film covering leaves, fruits, pear shoots. These are spores and mycelium of the fungus, so that the black does not infect the tree, and is not a parasite. The disease simply settles where the insects have already “worked”, releasing sticky juice when the green organs of the plant are destroyed.
The soot fungus actually harms the pear, although it does not directly feed on its leaves and flowers. But the mob covers them with a black coating that covers the stomata and interferes with photosynthesis. The disease depresses the plant, does not allow it to eat, breathe and fully produce chlorophyll. In fruits covered with soot fungus, the taste and appearance deteriorate, and the commercial and consumer value decreases.
Before fighting the mob, you need to destroy the cause that caused the appearance of the disease – pests. First, the pear is sprayed with an insecticide, and after 2-3 days – with a copper-containing preparation.
Cytosporosis
Pear leaves wither, branches and whole trees dry out – all these are signs of a dangerous fungal disease of pome crops of cytosporosis. The infection is introduced into the places of damage on the trunk:
- freezers;
- timely untreated wound surfaces left after pruning a tree;
- violations of the integrity of the cortex resulting from a sunburn;
- mechanical damage of any nature.
First, small pieces of bark become reddish-brown or brown-yellow, then dry out. Small swellings (fruiting bodies of mushrooms) appear on the dead areas of the pear. At the border with living tissue, cracks appear, populated by spores, and the disease spreads further.
Cytosporosis can proceed in a chronic form, destroying the pear slowly, or at lightning speed, when entire skeletal branches dry out in 1-2 months. According to the external signs and course of the disease, this is very similar to black cancer. The differences are that with cytosporosis, the bark remains red-brown, and does not turn black and is poorly separated from the wood.
Pear bacterial diseases and treatment
A group of diseases caused by unicellular organisms that enter plant tissues through stomata and pores, or injuries of any origin:
- timely unlubricated slices left after pear pruning;
- freezers;
- wounds left on leaves and fruits by insect pests;
- damage to the bark and shoots.
Outwardly, bacterial diseases of the pear appear as rot, the affected areas are first covered with oily spots, then turn brown and die.
pear bacteriosis
The disease manifests itself in spring with darkening of the edge of young leaves. Therefore, at the initial stage, it is confused with frostbite. Gradually, pear leaves turn completely brown, the disease spreads to petioles and shoots. On the cut of the branches, the darkening of the wood is visible – this is a lesion of the vascular system of the plant.
Pears of any age can be affected. Treatment consists in removing the affected branches and treating the tree with copper-containing preparations.
Bacterial burn
A dangerous infectious disease that proceeds quickly and often leads to the death of a pear. Bacteria, together with juices, are carried through the tissues and cause their death.
Treatment is carried out by spraying with copper-containing drugs or antibiotics. With a strong lesion, infected branches are removed. If the disease is left unattended for a long time, the pear may die.
Bacterial pear cancer (necrosis)
The disease causes damage to the skeletal branches and trunk, usually on adult fruit-bearing pears. First, small cracks appear on the bark, then they grow and turn into wounds surrounded by brown spots. The leaves and fruits of the pear turn red, the flowers and shoots turn brown. Then the vegetative organs dry up, but do not fall off.
On the saw cut of pear branches affected by bacterial cancer, dark rings and stripes are clearly visible. The disease softens the wood, it becomes brown, wet. Often in the spring, the bark first swells, then bursts and is left hanging in tatters.
This disease can easily be introduced to healthy plants if you immediately switch to work on a healthy tree from an infected pear. Insects take part in the spread of necrosis, but rarely. The bacterium often invades through apical buds and damaged areas, and occasionally penetrates through stomata.
The disease depresses the pear, reduces its yield, and sometimes destroys the tree. Even if the infection is detected on time and timely treatment is carried out, it is impossible to completely get rid of it.
Bacterial cancer on a pear can be prevented or slowed down, not cured. Anyway;
- the affected branches are removed, capturing about 10-15 cm of healthy tissue:
- saw cuts are treated with garden pitch or special paint;
- if the disease has spread to the trunk, it is cleaned by cutting out all the diseased wood and part of the healthy one;
- prepare a mash from a mixture of mullein and clay (1: 1), diluted to the consistency of sour cream with Bordeaux mixture, coat the wound surface with it;
- a dressing impregnated with a copper-containing preparation is applied on top.
Pear in spring and autumn is treated with copper-containing preparations.
Virus diseases of pear trees
Viruses enter the cell and multiply there. External manifestations of the disease:
- leaves become variegated (mosaic);
- vegetative organs are deformed;
- the leaves on the pear become small;
- parts of the plant die.
Peddlers of viral diseases are insects that carry infected cell sap from an already affected tree to a healthy one. Through dirty hands or a garden tool, hosts can infect pears and other fruit crops.
By and large, viral diseases are still a mystery even to scientists. There is no reliable way to deal with them, and affected plants often have to be destroyed in order to prevent the spread of infection.
Furrowing of wood
The striation virus is usually transmitted by plant grafting or pruning. Therefore, most often the disease affects young pear seedlings, which become infected at 2-3 years and do not live long.
External manifestations of striated wood:
- branches flatten, and eventually twist;
- young pear leaves turn yellow and fall off ahead of time;
- diseased wood dies;
- clearly visible necrotic furrows and spots appear on the cortex.
As a result, the connection between the crown and the root system is broken, the pear dies. It makes no sense to treat the disease, but the tree must be removed from the site as quickly as possible and burned.
A witch’s broom
Under this collective name may be hidden:
- fungal infection of a pear;
- viral disease;
- evergreen parasitic plant mistletoe.
Outwardly, they look alike and do not benefit the tree. But if the fungus can be treated, and mistletoe can be fought, then if the pear is affected by viral proliferation, the plant must be uprooted and burned.
At the site of penetration of the disease, dormant buds wake up and many thin shoots grow with underdeveloped, quickly shedding leaves. They tangle with each other and form a spherical cluster, really like mistletoe.
If this is a fungal disease, then there are light lumps on the shoots, the pear must be treated. Mistletoe can be recognized by its elliptical-elongated attractive leaves. It is impossible to get rid of the virus. The pear will have to be destroyed.
mosaic disease
This viral disease usually affects young trees. External manifestations become clearly visible closer to the middle of the growing season. The disease covers pear leaves with light green, yellow or white spots and intricately curved stripes. There are several mosaic strains that differ in the speed of propagation and the sharpness of the pattern. The venation of the pear leaf becomes clearly visible.
The virus has no cure. On mature trees, the external signs of the disease are weakly expressed. Only pale spots appear on the leaves of the most susceptible pear varieties to the virus.
Pear pests
There are many species of insects for which plants are not only a habitat, but also a breeding ground, an object of food. They can in a short time cause significant harm even to mature trees, and if measures are not taken to exterminate pests, destroy or spoil the crop.
Unfortunately, it is impossible to prevent the invasion of insects on pears and other fruit crops. But it is in the power of the gardener to destroy pests for at least one season and reduce their population.
Insects that parasitize plants are divided into two groups according to the nature of their diet:
- gnawing (beetles, caterpillars) – those who eat pear leaves and buds damage pear fruits;
- sucking (mites, aphids) suck the juices from the vegetative organs, piercing them with their proboscis, which causes the young leaves of the pear to turn yellow, the buds to crumble, the fruits to lose their marketable and nutritional value.
Hawthorn
Butterfly belonging to the Belyanka family with translucent white wings up to 7 cm in span, decorated with black veins. Caterpillars about 5 cm long hibernate in cocoons, from which they emerge during bud opening. Each butterfly lays 200-500 eggs.
The mass invasion of hawthorn, lasting 3-4 years, is replaced by a decrease in the number of the pest, lasting 6-7 years. In Our Country, the butterfly is common in Siberia, the Far East and the territory of the entire European part.
Hawthorn caterpillars cause significant harm to the pear – they eat buds, buds, and can damage up to 15% of the leaves. During the years of mass reproduction, they are able to completely bare the fruit tree. Parasitizing on pear leaves, the pest rolls them into a tube and tightens it with cobwebs.
Before bud break, the pear is processed:
- Nitrofen;
- Bicol;
- Lepidocidoma.
During the growing season, spraying is recommended:
- Tool;
- Heraldry;
- Samurai Super;
- Cyperus;
- Bitoxibacillin;
- Aliotom.
Pear tube turner
The pear is most harmed by adults during the laying of eggs – they roll the leaf into a tube, which makes it dry out. The pear or grape tube turner is a yellow-green beetle with a bluish tint, 6-9 mm long. They give one generation a year, each female lays up to 250 eggs – 8-9 in one “tube”.
Pests overwinter in the ground, burrowing 5-10 cm, a small part – under plant debris. At the end of April, immature beetles come out and eat pear buds.
To combat the tube-roller, you need to remove fallen leaves and dig up the ground under the trees. During the growing season, pears are sprayed with pesticides:
- Alfachance;
- Clonrin.
During the mass release of beetles from wintering, trees are shaken 3-4 times, pests are collected on a tarpaulin or agrofibre and destroyed. Straw impregnated with insecticides is laid out under the pears.
sawyer
A flying insect similar to a reduced fly with a yellowish-brown body and transparent wings up to 6 mm long is common in the southern regions. Adults are practically harmless, white-yellow larvae about 1 cm long are dangerous for pears.
The female lays eggs in flower buds, one at a time. The hatched larva does not come out, but feeds on the ovaries. After destroying one fruit, she moves on to the next. Before leaving for the winter, each caterpillar manages to spoil 1-3 pears. If nothing is done, up to 4% of the crop can be destroyed.
The larvae overwinter in the ground, pupae of them develop in the spring, long before the pear blossoms. By the time the buds appear, the sawfly has time to hatch and reach sexual maturity.
You can fight the pest by spraying pears 5-6 days before the buds open and immediately after the petals fall off with drugs:
- Fufanon;
- Zolon;
- Intra-C-M;
- Di-68;
- Iskra M.
The ovaries damaged by the sawfly are cut off by hand and destroyed.
Plodojorka
The pear codling moth is a butterfly belonging to the leaf roller family with a wingspan of 17 to 22 mm. It feeds exclusively on pear fruits, and prefers early varieties.
The upper wings are dark gray, decorated with transverse wavy lines and a brownish spot, the lower ones are reddish, with a gray fringe. Folding, they stretch along the abdomen. During the vegetative season, one generation of codling moths appears. Each female lays from 35 to 80 eggs, from which dirty-white caterpillars 11-17 mm long with a brown-yellow head emerge.
They cause the greatest harm to the pear, gnaw through the fruits, eat the seeds and fill the cavities with excrement. This stage lasts 22-45 days, depending on weather conditions.
The codling moth is most common in the southern regions and Siberia. With a mass accumulation, the pest can spoil up to 90% of the pear crop – the fruits eaten by caterpillars lose their consumer and commercial value.
Fall plowing will help reduce the insect population. The remaining caterpillars are controlled with organophosphorus pesticides by treating the pear before and after flowering. Recommended to use:
- Sail;
- Karbofos;
- Agravertin;
- Spark;
- Clinmix.
aphid
There are about 4 thousand species of aphids, they all parasitize plants and feed on their juice. Some damage pear trees, although one variety would be enough to classify the insect as especially dangerous.
Aphids not only pierce young vegetative organs and drink cell sap from them, releasing a sticky secret. They can spread viruses and other diseases, cause warts and other abnormal growths on pear leaves.
Aphids are small winged insects a few millimeters long. It is characterized by symbiosis with ants.
It is with the destruction of ants that it is necessary to begin the fight against aphids, otherwise all measures will be taken in vain. The natural enemies of the pest are beneficial insects:
- ladybugs;
- journal;
- lacewings.
Before bud break, pears are treated against aphids with an insecticide Preparation 30 Plus. Before and after flowering, the trees are sprayed with Litoks and Sumition, during the growing season – with Fufanon, Iskra M, Intra-Ts-M.
Of the biological preparations, Fitoverm is recommended. Good results are obtained by processing with folk remedies.
preventive measures
Spraying with pesticides and folk remedies give good results. But is it worth waiting for the leaves to turn brown on the pear, or some insect starts to gnaw them? It is better to prevent the occurrence of diseases and pests.
To do this:
- carefully carry out all sanitary measures;
- increase the tree’s own immunity;
- comply with the rules of agricultural technology;
- carefully cover with paint or garden varnish all damage, including those left after pruning;
- process a pear in the spring from pests and diseases;
- prevent frost cracks, sunburn and damage to the stem by hares;
- whiten the skeletal branches and trunk of a pear with milk of lime in autumn and spring;
- clean old bark;
- dig up the trunk circle in autumn and spring.
Disease-like problems can occur with improper care. For example:
- with a lack of phosphorus, bronze leaves appear on the pear;
- a critical lack of moisture causes drying of the vegetative organs and shedding of the ovary;
- overflows can cause rotting of the root system, the development of putrefactive diseases, and make the leaves on the pear purple.
Conclusion
Pear diseases affect a poorly maintained tree. It is easier for pests to feed on flabby leaves of a weakened plant. Only proper care and timely preventive treatments will make the pear healthy and allow you to get a good harvest.