Why are raspberries incomplete and small. Why raspberries dry and what to do? What do raspberries love?

Raspberry, although unpretentious, pays handsomely for care.

The raspberry season is almost over. Only remontant varieties can still please lovers sweet berry. This year's raspberries disappointed many: the berries are small, bony. Why?

We often treat raspberries like a weed - it grows and grows on its own. Usually summer residents dissuade: in the forest, she does without any care! Raspberry is really quite unpretentious. But if you follow the rules of proper planting and care, then she will thank you with a good harvest.

What do raspberries love?

Raspberries are quite light-requiring, in deep shade it does not bear fruit well. The acidity of the soil should be 5.5-6 units. And yet - raspberries love moisture. Large juicy berries ripen only if there was enough rainfall. And the past season was quite dry, so many of the berries went small and bony. Not everyone has the opportunity to water the entire garden, and it takes a lot of time and effort. And I am a supporter of the fact that the cottage was not a burden, but a pleasure.

This year I did an experiment. I usually have raspberries under a deep layer of mulch - peat, straw, tree leaves, rotted manure. So, I left part of the raspberries under the mulch, and the other part without it. So, where the raspberries were mulched, she gave large berries even though I didn't water it. Mulch itself retains moisture. And where the bushes grew without it, the berries were small and dryish. So in the spring, do not be lazy, mulch planting raspberries, and see for yourself that agricultural technology still needs to be observed! Some try to plant raspberries in low places, but raspberries cannot stand flooded places or places where groundwater is high.

Mulch is useful not only because it retains moisture. Gradually rotting, it becomes an additional food. And raspberries are quite demanding on nutrition. Therefore, with weak growth, bushes in early June are fed with manure infusion in a ratio of 5: 1 at the rate of one bucket for 4-5 plants. Moreover, it should be taken into account that remontant varieties “take out” more nutrients, therefore, the doses of fertilizers should be larger.

Nothing is eternal

The raspberry harvest could also disappoint because the raspberry, perhaps already old, degenerated. If he is more than five to seven years old, then in the fall you need to make new plantings. There are many things to take into account.

First, the choice of varieties is important. It is worth buying seedlings in a specialized farm. Would be nice to have multiple varieties. different terms maturation. And if you plant two or three more bushes remontant raspberry, which bears fruit from August to October, the period of consumption of fresh berries increases significantly.

Secondly, you need to plant seedlings in a new place where there were no raspberries. long time. Raspberries tolerate light shading in the morning for one to two hours, and the rest of the time it should be in the sun. It is convenient to plant in one row along fences and sheds - it is easy to approach from two sides to collect, tie up, serve. Best time for landing - August-September. Seedlings will have time to take root before winter and will begin to grow rapidly in spring.

It is not worth planting tightly, the harvest will not increase from this - the bushes will grow, the sun will not be enough for everyone, and the quality of the berries will suffer from this.

Neither deep nor shallow

When planting, you need to monitor the depth of planting raspberry seedlings in the soil. Large deepening should not be allowed - this will lead to the slow development and death of plants. A shallow planting leads to the drying of the basal buds and the formation of a superficial root system, which in dry summer period does not provide the plant with moisture, and in winter it can freeze slightly. After complete shrinkage of the soil root neck seedling should be at the level of the soil surface.

It would be nice to fence off the raspberry plantation from the rest of the plot: raspberries give a lot of root shoots and can flood areas that are not intended for it at all. To do this, you need to dig into the soil to a depth of about 30 cm, for example, boards. One of my acquaintances cut the barrels into rings and thus protected each bush individually. It looked, I must admit, not bad.

root system do not disturb!

Thirdly, the soil in the raspberries does not need to be dug and loosened. On the contrary, during the summer add mulch under the raspberries - for example, weeded weeds, mowed lawn grass. The root system of raspberries must not be damaged. The fact is that it consists of many dormant buds, and if we cut it when digging, then for the nearest bud it is a signal to jump out in the form of an escape. Thus, the raspberry thickens, depletes and is not up to fruiting - to feed the young shoots. Therefore, all young raspberry shoots must be weeded out during the summer.

Fourthly, one often sees the dry bare ends of raspberry stems. They are frozen in the winter. Raspberry bushes are advised to bend down to the ground and tie to the base of a nearby bush. Do not be afraid to bend down the raspberries. If this is done before frost, then the shoots will still be flexible, elastic. What does this approach give? In this form, raspberries winter well under the snow and preserve flower buds along the entire length of the run. When spring comes, fruit twigs are distributed along the entire length of the shoot and fruiting will be from top to bottom, which means that the harvest will come out richer.

Everything that worked - remove

Fifth, in the spring it is worth tying up all the overwintered shoots to a trellis of wooden stakes and wire. It turns out a beautiful, organized row of raspberries, which is a pleasure to work with all summer.

Sixthly, many, having collected the last berries from raspberries, forget about it until spring. This is mistake. It is necessary to cut the fruiting shoots, and the sooner the better. This brightens the raspberry row, the sun and wind contribute to the ripening of young shoots. And not everything that's cut needs to be dragged on compost heap. Leaves from cut shoots, small twigs can be dried and added to tea in winter, it becomes fragrant and fortified from this.

" Raspberries

Twice a year you can eat raspberries. Ripening begins at the beginning of summer, the second stage of fruiting - in September, when you can treat yourself to raspberries until the first frost. raspberry bush unpretentious plant, but it is also susceptible to various diseases. One of the most common is the drying of leaves, berries and shoots. In this article we will try to figure out why the berries, leaves dry and what to do in such cases, what are the methods of treatment.

The drying process is called withering away syndrome. Most young plants are susceptible to it, because with the growth of a shrub, young shoots crack. This contributes to the rapid penetration of insect larvae and phytopathogenic fungi, the main culprits of drying, into the interior of the stem.

• Disease caused by the reproduction of phytopathogenic fungi, manifested in the death of the stems in early spring. After winter, infected branches slowly grow back and dry out. If the plant does not have enough moisture, then the process is faster. If you do not take action, you can lose more than half of the stems and ovaries of raspberries.

Stems will crack more if they don't get enough water. Excessive fertilization of the soil with growth accelerators will also affect the integrity of the branches, because they do not have time to turf.

• The culprit of infection of raspberry bushes is gall midge. Getting through natural cracks or mechanical damage inside the stem, it lays larvae that feed on the bark of the plant and destroy it. protective layer- periderm. This is the main barrier that prevents the penetration of phytopathogenic fungi into the interior of the plant.

Shoots become a feeding trough for larvae. In place of their greater accumulation, ulcers appear that prevent the spread of nutrients throughout the plant. This leads to the death of the upper part of the stem. The disease manifests itself in the form of purple or dark brown spots on the shoots..

Why do berries dry up?

The drying of raspberries is facilitated by various viral diseases that are spread by cicadas and aphids. These sucking insects carry the infection from diseased plants. The diseases are different, but the result is the same for everyone - the drying of the berries.

• With viral chlorosis of the berry develop poorly, do not have time to gain juice and color, and eventually dry out.
• With a yellow mosaic if the berry does not completely dry out, then it develops unilaterally and has a dryish, insipid taste.

• Curly characterized by underdevelopment of berries and their drying. Bushes infected with this virus die within a few years.

First of all, diseases affect the crop. The one-sided development of berries, their shedding and drying should be a signal for the start of emergency action.

Why do leaves dry and curl during fruiting?

Viral and bacterial diseases of raspberries, spread by flying insects, provoke the drying of the leaves, even during fruiting. Diseases that affect berries primarily affect the condition of the leaves and their development. The same viruses have a negative effect on the plant and yield:

1. Viral chlorosis. Infected leaves begin to turn yellow, dry and curl in the midst of growth and flowering along with berries, shoots become small compared to healthy ones.
2. yellow mosaic. This disease is characterized by yellowing leaves with twisted dry edges. It is an insect-borne virus that appears in late spring and mid-August.
3. Curly. You can distinguish healthy shoots from diseased ones by several signs:

• slowdown growth;
• thickening in diameter;
• leaf color change to brown;
• reduction in leaf size and their drying.

Viral chlorosis Wishing mosaic
Curly

What is chlorosis and how to treat it

A disease that is often infected raspberry bush, is chlorosis. His by nature of origin are divided into:

What does a bush affected by this virus look like:

• turning yellow first in the center, then the whole leaves;
• shoots are thinning and pulled out
• berries or not formed at all, or half matures, and the other half dries.

Chlorosis should be dealt with immediately after planting. For this, there is a whole a range of products for spraying the plant and protecting it from sucking insects. If you want to harvest this year, then you should process in 2 stages:

• In early spring, before bud break, use a 3% solution of Nitrafen or a 0.2% solution of Nicotine sulfate.
• Before flowering emulsion of 30% Methylmercaptophos.

Before raspberries begin to ripen after spraying, at least 45 days must pass.

If chlorosis was provoked by unfavorable weather conditions, watering cold water or lack organic compounds, you have to try improve the quality of plant care:

• normalize watering warm water , it is better if it is river or lake, heated in the sun;
• make the soil more fertile through the application of mineral fertilizers;

• soften the ground forest floor or peat.

Remember that it is easier to protect against the disease than to cure later.

How to protect raspberries from pests and diseases

Mulching is one way to protect. By protecting the roots of the plant, such a surface layer will allow the plant to get stronger and push back the process of cracking the stems when they become resistant to the disease. The mulch layer must be removed when the first buds appear. The soil under it is always saturated with moisture, this can cause rotting, death of the kidneys and eventually drying out.

Mulching is one of essential conditions preparing the plant for winter. It prevents freezing of roots and shoots, prevents the evaporation of moisture and protects against constant winds in some regions.

If you cut off the damaged stems in time, you can save part of the shrub. You need to cut off all areas covered with dark spots and small growths.. It will be better to remove the entire "sick" shoot completely.

Let the bush grow stronger and grow, spraying will help, which must be carried out during a period of rapid growth, at the beginning and in the middle of summer. The lower part of the plant is processed, from the ground level by 25 - 30 cm upwards. For this, mixtures of Aktellik - 0.2%, Fufanon - 0.3% and Topaz - 0.1% are suitable. Fruiting raspberries should be sprayed with the same preparations before flowering and after harvesting. In order to preserve the integrity of the berries, after flowering, 3 treatments with the Fitoverm biological product should be carried out - 0.3% with an interval of 1 week.

Proper planting of young plants

How new bushes are planted will depend on their resistance to gall midge larvae and viral diseases.

• Young plants should be planted away from old bushes, which can be infected with larvae and fungi.

• It is necessary to wash the roots under the pressure of water and wash all the soil from them. It is recommended to dig a small hole nearby, where water and soil residues will drain. The roots may contain unhatched gall midge eggs that need to be neutralized, i.e. bury.

Roots should be placed on a hard surface or placed in metal mesh so as not to damage.

• After landing completely cut raspberry stalks even if you plant in the spring.

If possible, raspberries should be covered nonwoven fabric to prevent infection with viral infections that are carried by flying insects.

Once every 2 weeks, spray with Bordeaux mixture or other chemicals allowed for raspberries. During this period, it is important high yield while strengthening the stems and protecting against pests and diseases.

In response to these statements, the seller said that agricultural technology must be observed, and not complain about varieties. The buyer just waved his hand, saying that this was a common excuse.

Let's try to figure out who is right and who is wrong. I have seen large-fruited raspberry varieties with a harvest not only at exhibitions, but also in nurseries and experienced gardeners. I met the same varieties on “amateur” sites.

Let's take a look at my observations together and conclude: what raspberries love and how to please them.

First of all, it must be said that the approach to growing large-fruited varieties is completely different for amateurs and professionals. Most gardeners believe that by replacing their ordinary raspberries with large-fruited ones, they will immediately receive a crop of super-large berries (while not changing anything in agricultural technology).

Experienced gardeners and agronomists understand that all modern varieties create and grow on a high agricultural background. Without it, good results cannot be achieved. Getting, to put it mildly, into “average” conditions, the variety begins to degrade and produce “average” berries, slightly larger than usual. Agronomists love to repeat one wise phrase: “Even the most good grade can be ruined by poor agricultural technology.”

Basic Mistakes

growing raspberries

1. Lack of light. We honestly admit that for raspberries we have not the most best places. Where does it grow most often? Along a fence, behind a house, a barn, or in a corner of a garden behind large apple tree. Is there enough lighting there? As a rule, no. This is the first mistake.

Raspberries need a lot of light. Remember, in the forest the most good raspberry grows on clearings. Therefore, plant it in a completely open area.

2. Planting raspberries on raspberries. It often happens that new varieties are planted in the same place where old raspberries grew. The owner believes that he carefully cleared the site from the previous plantings and removed all the roots. But this is a delusion! It is impossible to remove raspberries without a trace! It sprouts even from the smallest roots.

Sometimes old raspberries are not harvested at all (they regret it), but a new variety is planted nearby.

What happens? As new seedlings grow, they begin to give offspring. At the same time, old raspberries also sprout. It is extremely difficult to distinguish these shoots. Moreover, some large-fruited varieties give very little shoots (especially at a young age). At the same time, old varieties “creep” in all directions. As a result, the gardener begins to propagate his old raspberries by layering. Naturally, he gets small berries from her, and then “shifts” the blame on a new variety.

Let's not forget that according to the rules of agricultural technology, a change of crops should be observed. An apple tree is not planted after an apple tree and another place is chosen for it. But it is customary to plant raspberries along the border of the garden, and, as you know, there is only one border. So new varieties fall into the same place.

Remember, you cannot plant raspberries after raspberries! Highlight for new seedlings

a separate area away from the old bushes.

3. Preparation of the landing site. The soil in most garden plots is not fertile. Therefore, before boarding, you need to pay organic fertilizers. Often this rule is ignored. In a hurry, the earth is only dug up and the purchased plants are planted.

Raspberry loves fertile soils. This is noticeable even in the forest. The largest berries ripen on bushes that grow in a small depression, where more forest litter has accumulated, that is, where there is more humus.

According to the description, modern varieties yield 6-7 kg per bush (record - 10 kg). To achieve such results, experienced gardeners, when planting, add 1 bucket of rotted manure to each hole and liter jar ash. Everything is mixed with the ground and raspberries are planted.

4. Quality of care. Compare how we cherish and care for Victoria (large-fruited strawberries). For her in the garden - the most honorable place. And for some reason we regret the place for raspberries. But why is she worse? Her growth is too high, and even forms thickets. I don't want to ruin the view.

And you do not allow to thickets. If the raspberry grows uncontrollably, it obscures itself, it lacks nutrition. This is the biggest mistake! All this leads to the degeneration of the variety. On the contrary, well-groomed plantings of raspberries give a bountiful harvest of large, sweet berries. This is a real pride and decoration of the garden!

Take care of your raspberries. Avoid overgrowth. In the spring, tie the bushes to a trellis or stake. In the summer, remove small shoots, plant layering. In autumn, thin out the bushes completely or cut them off completely (for remontant or “annual” varieties).

5. Watering. A very common mistake is lack of moisture. Many gardeners do not understand that in addition to precipitation, raspberries need additional watering. After all, no one waters it in nature. But on the other hand, in the forest, the largest berries are given by bushes that have grown in a small hollow, where moisture from the rain lingers longer.

Sometimes the lack of watering is associated with a banal reason - the hose to the fence where the raspberries are planted simply does not reach. And if the length is enough, then they don’t linger near the raspberries for a long time: they only moisten the ground from the hose, and water does not penetrate to the depth of the roots.

Raspberries love moisture. Water it abundantly. Norma - a bucket of water on an adult bush. Watering frequency - depending on the weather. The soil under the raspberries should always be moist.

To prevent water from spreading during irrigation, it is recommended to plant raspberries in a trench. After planting, its depth should be 10-15 cm from the soil level. The width must be made about a meter, then the moisture is more evenly distributed in the root zone. It is advisable to strengthen the sides with boards so that over time the trench does not become level from precipitation and watering.

6. Mulching. This agricultural technique is recommended for all crops. But few people use it for raspberries. What does he give? Retains moisture in the soil. Prevents the growth of weeds. Prevents the formation of a crust on the soil and keeps it loose. Protects roots from snowless frosts. Prevents the growth of pests in the soil. All this improves the conditions for the growth of raspberries and increases its yield.

For raspberries, not only good soil moisture is important, but also a sufficient amount of air for the roots. If you do not use mulching, then you often have to loosen the soil. This leads to damage to the roots, as they are very superficial in raspberries.

The term “mulching” is relatively recent. But the approach itself is far from new. In the old days they said that raspberries love "all kinds of garbage." Therefore, they carried any organic matter under it: in the fall - bedding from livestock (straw manure), in the spring - small twigs from pruning, in the summer - mowed grass and weeded weeds. By the way, it is the presence of small branches along with other organic matter that makes the soil especially loose, with an abundance of air.

Raspberries need to be mulched. This should be done at least twice a year: in the fall before the onset of cold weather and in early spring before the start of the growing season. In summer, it is advisable to pour mulching materials as they dry on

I did everything right!

At the exhibition, the offended buyer assured that he grew raspberries in accordance with all the rules, but did not receive the promised super-berries. What's the matter?

In defense of a diligent gardener, the following can be said. The basis of new raspberry varieties was a special large-fruited gene. External signs the plant that retains this gene has long sepals. The disadvantage of this gene is its instability. That is, part of the varietal plants (a small percentage) produces ordinary fruits. During flowering, short sepals are visible on such shoots. This is not a disease, but the return of the plant to its natural state.

In this regard, the reproduction of large-fruited varieties requires special care. Shoots with short sepals must be ruthlessly disposed of. But in the pursuit of profit (or out of ignorance), nurseries do not always comply with this requirement. That is, among the seedlings of real large-fruited varieties, reborn plants can also come across. Therefore, it is best to buy raspberries in reliable, proven nurseries. Or come to the nursery yourself and choose seedlings on the spot.

How to determine the authenticity of a large-fruited seedling if at the time of sale (in spring or autumn) it does not bloom and does not have the same sepals?

Experienced gardeners convince that raspberries can be planted throughout the summer. First, most varietal seedlings are now sold in containers or bags. And secondly, in the summer, raspberry seedlings take root well if you dig them out with big ball earth. Only the shoots must be shortened (up to 40-45 cm)! Spill the hole well with water and put a peg. After that, cover the roots with earth and water again. Mulch the soil. Wrap the plant with a spunbond or sheet to protect from the sun. With this planting, the survival rate of plants is 100%.

Without proper care, large-fruited varieties still show their properties and give berries larger than usual. However, they never reach their maximum dimensions. In the photo, just such a case: in the center - a berry ordinary variety and large-fruited variety Patricia. Subject to all requirements, Patricia's berries grow larger.

Large-fruited varieties raspberries Arbat, Generalisimo, Pride of Russia, Beauty of Russia, Abundant, Divine, Paradise pleasure, Inaccessible, Ideal, Patricia, Tarusa, Just lovely, Maroseyka, etc.

For comparison. A good garden raspberry gives berries of 3.5-4 g. Large-fruited varieties - 14-18 g each, and the most outstanding ones - up to 23 g. Modern remontant varieties berries weigh up to 12 g.

Material prepared

You can find this article in the newspaper "Magic Garden" 2010 No. 10.

Number of impressions: 25948

When the berries of a delicious and vitamin berry are sick, or appearance clumsy, here you can already make a diagnosis - a disease. And if this still happened, then you need to sanitize the bushes.

It is necessary to dilute the solution against the fungus and treat the bushes with it, otherwise all plantings may die completely.

If you have grown a variety that was previously large-fruited, then agricultural technology also plays an important role. This usually happens when there is no proper care and attention to the bushes of this plant, everything grows by gravity.

First you need to take a pruner and cut out all the weak shoots, this includes young ones. It is necessary to pay attention to the fact how the earth was loosened, whether its roots were damaged.

If so, then the berries will be small. You can correct the situation, for this purpose manure is introduced, and the depth of loosening is also reduced to three or five centimeters.

Pay attention to whether you feed this plant on time, this must be done once during flowering.

So that the raspberry does not undergo the disease, it must be treated with Fufanon before it blooms, according to the instructions.

Once a week, you need to set aside time and inspect all the shoots of the plant. The soil can be depleted and lead to such consequences. This happens when bushes grow in one place for many years.

Every six to eight years, a plantation with bushes should change its place of residence. Don't forget to eliminate all weeds.

Material prepared:

Deputy President of the Association of Gardeners of Russia (APPYAPM), Leading Specialist of the APPYAPM for berry crops

d.s.-x. n., Professor, Saratov State Agrarian University named after V.I. N.I. Vavilov "

Danilova T.A.

Specialist of APPYPM, student of MichGAU

Using the material of Prof. Edward Żurawicz, Dr. Miroslava Cieślińska

The results of studying the influence of viral diseases and external conditions on the quality of raspberries on industrial plantations

Industrial raspberry plantation

Raspberries are the most common berry crops and one of the fastest growing. Flowers almost never fall under return frosts, since raspberries bloom later. Another advantage of raspberries is long-term fruiting. Proper organization berry conveyor - selection of the optimal assortment, the use of special technological methods, which allows you to get fresh raspberries from June to October.

The ratio of varieties for an industrial plantation

Raspberries are one of the most ancient berry crops in our country, and one of the most popular. It can grow in various soil and climatic zones. Most raspberry varieties have sufficient winter hardiness and do not need special pollinator varieties. However, when cross pollination raspberry yield is increasing.

Raspberry cultivars are descended from two species: the red raspberry, which has several subspecies, and the blackberry, or black raspberry.

Red raspberries contain a large number of carotene, vitamins C, B 1, B 2, B 6, PP, E and other useful substances.

Red raspberries are more common and are used fresh and processed.

Monitoring soil pH with a pH meter

Raspberries should not be planted on soils that are too heavy or close-lying. ground water. The reaction of the soil solution (pH) should be slightly acidic.

Raspberries are a complex multidrupe. The drupes are located on the receptacle. An important role is played by the strength of the drupes. At ripe berries raspberry drupes are easily separated from the receptacle. When forming fragile berries, the drupes disintegrate during harvest. These fruits do not have a commercial value, since in this case the presentation is completely lost.

Fruits from non-pollinated flowers are usually smaller and ripen unevenly, they can be colored on one side and remain green on the other. These signs can only be observed in berries during the ripening period.

Red raspberry leaf, cv. Molling Jewel, affected by raspberry ring spot

It has long been known that the formation of fragile, decaying drupes can be a consequence of the defeat of some viruses. One of these is the MIDORA ring spot virus (so-called tomato ring spot virus ToRSV), which is transmitted by soil nematodes. Observations have shown that severe lesions caused by ToRSV even lead to growth retardation, uneven fruit set. In addition, the development of the virus contributes to the decay of berries during harvest.

Various types of virions under an electron microscope, magnified 135,000 times. Raspberry ring spot virus

Resistance to the virus also depends on the raspberry variety. The Canby variety, which is not resistant to it, is widely cultivated in areas with a warm climate (USA, Canada, Western Europe), variety Villa-Mette has a relative resistance to ToRSV. Despite all the signs shown on the leaves, the berries on the bushes are not affected by the virus, they correspond to the norm, have correct form and uniform color.

Ringspot virus is transmitted by nematodes, while raspberry mosaic virus (TBRV) is transmitted by aphids. There have been cases of total loss in the past presentation raspberries of the Latham variety from the mosaic virus.

Mosaic virus-infected raspberry plants

A mosaic of raspberries is seen as viral disease, including:

• a) the ability is transmitted by aphids between hosts of Rubus Amphorophora rubi (Kalt.) and A. agathonica Hottes.
• b) manifestation of signs such as necrosis of the tips of the shoots and (or) their mottling, if transferred to susceptible clones of Rubus henryi Hemsl. et Kuntze or R. occidentalis L. Vein chlorosis viruses are not considered part of the raspberry mosaic virus group because they are not transmitted by Amphorophora aphids.

Raspberry dwarf virus

The raspberry double dwarf virus (called RBDV), which is carried by pollen and seeds, can also be the cause of crumbling berries. This most commonly occurs when the pathogen is Black Raspberry Necrosis Virus (aka Black Raspberry Necrosis Virus - BRNV) transmitted by aphids. Damage to raspberries by a complex of RBDV, ToRSV and TBRV viruses, in addition to many other symptoms (leaf spot, growth inhibition, shrub dieback), also causes shoot deformation.

Phytoplasmic diseases of raspberries can also be the cause of fragile fusion of drupes. This pathogen causes flower degeneration. Small ripening fruits are scattered during harvest. The problem of the decay of red raspberries is known to berry growers not only in Eastern Europe. Viruses are undoubtedly the cause of this, but not always the primary one. A more detailed analysis of these issues is presented at the meeting of the European working group German researchers in Dublin (Ireland). The results of a study conducted over many years in the Baden-Württemberg region, which is one of the provinces in southern Germany where a relatively large gross harvest of raspberries is obtained, were discussed. The presented works show that the problem of the decay of raspberries is quite common and well known to berry growers. A survey of farmers showed that raspberry yield losses range from 5 to 30%, depending on the year. However, so far, it has not been possible to find a clear relationship between berry decay and soil type, pH, agricultural practices prior to planting raspberries, soil organic matter content, and herbicides used. Insignificant nitrogen content in the soil is likely to limit the decay of berries, and the frequent establishment of new stands due to planting material from existing plantations is likely to contribute to this problem.

I.V. Mukhanin demonstrates high-quality photoneutral type raspberry cultivar Polka

The literature describes many causes of this disease, genetic and physiological. Studies conducted in research centers in the USA and Canada have proven the fact that the cause of the decay of berries can be: somatic mutation of individual clones of some raspberry varieties, disturbances occurring in the process of meiosis, damage to flowers, as well as hereditary factors. This is confirmed by the results of an experiment in Germany, which used plants of the variety Schönemann with pronounced strong signs of berry decay.

During the first year of observation, 20 to 40% of decaying berries were found on plants of the Himbostar and Malling Promise varieties, almost none of them were found in the Glen May and Schönemann varieties. Interestingly, during the second year of the study, berry decay was observed in the Himbostar variety, while it was not observed in other plants. It should be added that neither pathogens nor signs of the disease could be detected on the plants.

Raspberry varieties Malling Promise

The appearance of decaying berries at harvest also depends on external factors(e.g. temperature, soil moisture). Studies have shown that not all viruses that infect plants cause berry disease. In addition, it was noted that plants that in one year have crumbling fruits, on next year characterized by normal berries. Therefore, it is believed that internal factors can change the effect of viruses on the quality of raspberries.

The reason for fragile berries can also be the lack of good pollination and fertilization. Fewer crumbling berries were found on plants with free pollination. Microscopic studies have shown that two seeds are formed in an uninfected raspberry, one of which then degenerates. In the event of the decay of the berries, both seeds degenerate.

The reason for the decay of berries is the wrong agricultural technology of raspberries, and in particular, the lack of an “in vitro” health improvement system. The results of the survey, which included many German raspberry growers, confirmed that more problematic berries were found in plantations established using planting material from industrial plantations than in plants obtained "in vitro".

Growing raspberries in vitro

Plants of the cultivar Schönemann were compared in the fourth and fifth years of cultivation on plantations established using the traditional method and using cuttings obtained "in vitro" (1997 and 1998). In the material obtained "in vitro", it was not possible to establish which kidneys were used - apical or lateral (axial). The plants of traditional breeding both years had the same number of crumbling berries. Plants grown "in vitro" behave differently. In traditionally propagated plants, all the berries decay during harvest, while in test-tube plants, usually 1-2%.

As a result of the research, it has been suggested that the strength of berries can be affected by the content of cytokinin (growth regulator) in the medium in which raspberries grow while in vitro. More or less significant correlations were found.

As one of the reasons for the possible decay of berries, one should consider the impact climatic conditions. It is necessary to remember about the decay of wild raspberry berries ()