The preservation of fresh apples and pears in the winter is affected by various diseases that could occur on the fruits on the tree. By their nature, they are all divided into physiological, caused by a violation of the internal processes of tissues, and infectious. Therefore, it is not necessary to be upset that there are holes somewhere in apples and pears, somewhere a rotten barrel, and somewhere an ugly shape. It is necessary to draw conclusions in order to prevent these diseases in the next year. This article will help you with this.Why do apples and pears rot during storage?
Physiological diseases of apples and pears
Bitter dimple (subcutaneous spotting)
It is found either on a tree or after 1.5-2 months of storage. It has been observed that bitter dimple is more often found on larger fruits that have grown in shading.
On the fruits appear deepened to a few millimeters, small, green on yellow, or dark purple on red apples, unevenly rounded spots, more often - on the one hand, around the calyx. Over time, the spots turn brown, and the affected areas acquire a spongy and bitter taste.
The causes of this disease can be:
- lack of potassium;
- excessive pruning;
- high doses of nitrogen;
- high humidity in the spring and summer;
- untimely late harvesting of fruits.
Tan (superficial burn, skin browning)
It can be detected at the time of harvest, and may occur at the 4-5th month of storage. Fruits taken ahead of time are more affected by tanning than harvested at the optimum time for their variety.
It appears in the form of light brownish or bluish-greenish spots, which eventually become covered with brown spots. Gradually, the affected areas grow and can cover not only the entire surface of the fetus, but also subcutaneous tissue. The fruit rots.
The causes of a superficial burn can be:
- thickened crown;
- lack of potassium or phosphorus;
- excess nitrogen;
- excess moisture in late summer or early fall;
- too high temperatures during the ripening period of the crop.
In the storehouse, the manifestation of these symptoms can be triggered by a temperature drop or high humidity.Bitter pinched apple (subcutaneous spotting). Tan (superficial burn, brown skin) apple.
Wet burn (low temperature)
This physiological disorder of apples and pears manifests itself in storages if the temperature regime is not observed, or rather, in low temperatures. It appears in the form of an irregular shape of brown, indented spots or ribbon-like areas with a sharp border. The pulp of the fruit under the spots becomes watery, brown.
Reasons for the development of burns:
- harvesting well-ripened fruits in cold weather;
- a combination of inadequate air circulation, high humidity and low temperatures in the storage.
It occurs due to rupture of part of the walls of the fetal cells, due to which the intercellular space fills the cell sap. Fruits affected by glassiness lose their characteristic taste and become tasteless. The provocateur of the phenomenon is the difference in osmotic pressure in the cells of tissues and the intercellular space, which provokes a rapid transition of starch into sugar.
Reasons contributing to the development of vitreous apples and pears:
- lack of potassium;
- late eating of fruits, coinciding with cold weather;
- improper storage conditions - increased humidity combined with low temperatures and insufficient air circulation.
Swelling (swelling, powdery decay of the fruit)
Manifested in the loss of tissue of the correct consistency. In affected fruits, the flesh becomes loose, becomes powdery, bursts, sometimes to the very core of the fruit.
- high doses of nitrogen were introduced;
- the tree received less calcium;
- late harvesting.
Beating the core of apples and pears
This disorder occurs as a result of prolonged storage. It manifests itself in the form of browning of fetal tissues around the seed chamber (and sometimes with it). In appearance, this process is not reflected.
Contribute to the phenomenon of:
- excess moisture in terms of fruit ripening;
- long-term storage;
- violation of storage conditions (poor ventilation, high or very low temperature).
It occurs when the fruit loses up to 5% of its mass. Usually manifests itself in the wrong storage mode of apples and pears - high temperature or low humidity. In addition, the late harvesting also contributes to the development of this disorder.
It develops for two reasons: either as the natural aging of apples and pears during very long storage, or due to the low temperature regime of storage. It manifests itself in the appearance of sharply delimited browned zones of pulp, sometimes with the capture of the seed chamber. In the later stages of development, it also appears on the skin in the form of large, fuzzy, bluish-green spots.
Contribute to the development of this disease:
- lack of calcium;
- increased doses of nitrogen;
- late harvest.
How to store apples and pears with physiological diseases?
In most cases, physiological problems of fruit storage arise due to improper nutrition of plants from which they were removed. To prevent this, you must comply agricultural technology fruit cultivation: nutritional deficiency correction, proper fertilizer application, regular watering, proper pruning, timely harvesting.
If there is a lack of calcium in the spring, already 10 days after the end of flowering, with an interval of 15 days, it is recommended that a cycle of treatments (from 4 to 8) on foliage with preparations containing calcium is recommended.
They help preserve apples and pears with physiological diseases proper preparation and then storage fruits: timely harvesting, rejection of fruits with signs of damage, immediate storage, compliance with temperature and moisture storage conditions (read about this at the end of the article).
Read also our material. Why do apples rot on branches?
Microbiological diseases of apples and pears
This category includes fruit damage associated with fungal diseases - various rot.
Fruit rot (monilial rot, moniliosis)
The cause of the disease is the fungi Monilia fructigenum and Monilia laxa, which infect apples and pears on the tree through mechanical damage. Often a lesion is already apparent in the garden. If not, then in the conditions of improper storage mode in the repository.
One type of lesion begins to develop with a small rapidly growing brown spot, which gradually covers the entire surface of the fetus. Simultaneously with the expansion of the borders of the rotten tissue, concentrically located light pads of conidia are formed on its surface. Over time, the affected fetus dries out, mummifies. If the disease manifests itself in the repository, it is transmitted to neighboring fruits.
If the infection with the fungus was late or occurred at the time of preparation of the removed fruit for transportation, the second type of disease development manifests itself - darkening of the fruit. The entire surface of the apple (pear) gradually blackens (acquires a bluish-black color), becomes shiny, smooth, leathery. With this manifestation of the disease, sporulation is often not observed, so neighboring fruits do not become infected.
Moniliosis is easily recognized by several other signs: the flesh softens, becomes spongy, brown-brown, acquires a sweetish-wine taste.
Bitter rot (gleosporious rot, anthracnose)
The most common disease. Called immediately by a number of fungi - Gleosporium album, Gleosporium fructigenum, Gleosporium perennans.
Mushroom spores affect the tissues of apples and pears even on trees during wet weather, through lentils that have not had time to try out. They remain in a sleeping state until the fruit is fully ripened. They begin to develop already during storage. Symptoms may vary depending on which fungus is affected.
- The disease develops on well-ripened fruits in the form of several adjacent, rounded, sharply defined, depressed, brown spots with light concentrically arranged small sporulation pads.
- Sharply limited brown spots appear, which are quickly pressed in. The sporulation of the fungus is located under the skin, which breaks with time, and the pulp in the center, due to the released conidia, appears pink.
- Small rounded, slightly depressed spots appear, which quickly increase to a size of 4-8 mm, in other cases 30-35 mm. A dark border, 2 mm wide, is outlined along the contour of these spots. On the surface there are gray sporulation pads.
The fruits acquire a bitter taste. Mummified.
Infection occurs even on trees. Small, dark, clearly defined spots appear on the skin of the fruit in bulk. If the lesion occurred early - apples and pears grow with deformities, cracking forms on the affected areas. If at full ripening, the spots form very small, weakly visible, and are more pronounced already during storage, the fruits wither or are additionally affected by rot.
The causative agent of scab, barn form - the mushroom Fusicladium dendriticum - on apples, Fusicladium pirinum - on pears.Apple fruit rot (monilial rot, moniliosis). The bitter rot of an apple. Scab pears.
Gray rot (botrythic rot, botritis, gray mold rot, focal rot)
Called by Botrytis cinerea, which penetrates the fruit through a calyx or skin lesions.
The development of the disease begins with slightly depressed brown areas that grow and capture the entire surface of the fetus. The affected areas turn brown, covered with a cotton-like mushroom coating. Damaged apples and pears smell sour.
If the summer season turned out to be rainy, apples and pears infected with focal rot rot in the trees.
Blue mold (blue mold, penicillus rot, gray mold, penicillosis)
The causative agents are the fungi Penicillium expansum and Penicillium digitatum. Disputes fall into the fruit when the skin is damaged.
The manifestation of the disease begins with a small watery (putrefactive) speck, which gradually grows not only on the surface, but also in the depth of the pulp, is slightly pressed and becomes folded. If you press it lightly - the skin breaks easily, releasing moisture. The disease progresses, a white mycelium appears on the affected area, and then a bluish sporulation in the form of many grayish-greenish, greenish-bluish pads. Spoiled apples and pears have a smell and taste of mold.
The bluish mold is able to develop under the storage mode 0 ... -2 C, but the higher the temperature, the more intensive its development.
Olive mold rot (alternariosis)
The causative agent of the disease is the fungus Alternaria tenuis Nees. It infects fruits in the garden through various kinds of mechanical damage (insect bites, hail, blows), however, the manifestation of the lesion begins at the end of the storage period, when apples and pears over-ripen.
Damage to the fetus begins with a dark brown or black dense spot of irregular shape, which over time becomes covered with an olive velvety coating.Blue pear mold. The initial stage of olive mold of apple.
Black Rot (Black Cancer Rot)
The causative agent is the fungus Sphaeropsis malorum Pk. Penetrates apples and pears in the garden. It begins to appear with a small brown spot, slowly growing and covered with black, concentrically located tubercles - mushroom picnids. Further, the fetus turns black and mummifies. But if, when apples and pears are blackened as a result of defeat by moniliosis (fruit rot), the skin of the fruits has a smooth surface and a bluish tint, then when damaged by black cancer, due to the abundance of pycnids, it is simply black, rough.
The main source of infection of the fruits of apple trees and pears with black rot is the bark of trees affected by cancer.
Focal rot (botritis, gray mold rot)
The defeat of the fruits occurs even on the tree, through lentils and damage to the skin. The causative agent is the fungus Botrytis cinerea Pers.
The manifestation of defeat begins with a dark brown, slightly deepened rotten spot. As the disease develops, the affected area is covered with a cotton-like mycelium of the fungus. Mold quickly spreads to neighboring fruits, resulting in whole "nests" of rotting apples and pears. Rotten specimens have a sour musty smell.
In another embodiment, a small spot of rot (up to 2 cm in diameter) can develop only near the calyx.
In rainy summers, botritis-infected apples and pears rot on the tree.
Fusarium rot (Fusarium)
The causative agent is the fungus Fusarium avenaceum (Fr.) Sacc. The future crop is striking even in the flowering period, penetrating the embryo sac, and the disease manifests itself already at the time of fruit ripening.
The lesion develops in the inner part of apples and pears - in the seed chamber (whitish-pink or dark sporulation pads are formed), then in the pulp and only then on the surface of the fruit (a whitish, gray or yellowish cotton-like coating sometimes forms in small bunches).Black rot of apple on a tree. Focal rot of a pear. Fusarium rot of an apple.
The causative agent is the fungus Cladosporium herbarum. It affects the fruit still on the tree. On the skin, small brown (often oval) heavily buried, sharply limited areas of rot, which quickly grow into spots of irregular shape with partial staining in black, initially appear. In conditions of high humidity, brown pads of sporulation of the fungus grow on the affected areas.
Ways to prevent rot of yalok and pears
- Selection of scab resistant varieties.
- Compliance with agricultural technology of culture, including timely cleaning of plants from mummified fruits, sanitary and thinning pruning of trees, chemical methods of combating diseases and pests.
- Disinfection of storage and recycled containers.
- Timely eating fruits.
- Culling fruits with signs of disease.
- Careful removal and packing in containers to prevent skin injuries.
- Compliance with temperature and humidity storage conditions.
Read also our material of the 15 best varieties of pears for the middle strip.
Basic rules for storing apples and pears
It is necessary to disinfect the premises reserved for storage of apples and pears in advance, no later than 20 days before the fruits are picked. Various means are suitable for disinfection: sulfur checkers (if the store is located at some distance from the apartment building), whitewashing with a 15% solution of lime with the addition of 2% copper sulfate.
The storage temperature of apples and pears on average is + 0.5 ... + 1 ° C (up to + 5 ° C), with a humidity regime of 80-90% with ventilation. However, such widespread varieties of apples as "Antonovka" and "Winner" at a temperature of below + 4 ° C are affected by the turning of the pulp. For most winter varieties, the recommended temperature range is -1 ... + 2 ° C, with a relative humidity of 90-95%.
It is easy to raise humidity in the storage by hanging wet burlap or water plates.
When harvesting for storage, it is necessary to carefully inspect each fruit, discarding anything that has signs of disease damage, as well as deformity. Lay out products in disinfected boxes and refrigerate immediately. Apples and pears left at elevated temperature for a day lose their shelf life by about two weeks!
During storage, apples and many varieties of pears emit ethylene - a substance that enhances the aging of plant tissues. For this reason, they are stored separately from other stocks - vegetables, grapes.