Dry rot, or fusarium, is a fungal disease that affects the above-ground parts of potatoes during the period of growth and development, and usually appears on tubers during storage.
Causes of dry rot on potatoes
The source of this infection most often is the soil in which the fusarium fungus persists for a long time, the remains of leaves, tops and contaminated soil, which ends up in vegetable stores along with the tubers. The fungus clogs the vascular-fibrous bundles of the stems, and the plants quickly wither and dry out. Grayish-brown spots first appear on the tubers, then the peel wrinkles and the flesh dries out and rots.
Fusarium usually appears 2-3 months after harvest and. Dry rot quickly spreads throughout the tuber, but it remains light and dry. White or pink sporulation pads develop on the surface of the potato tuber. From these, the disease is transmitted to healthy tubers.
Most often, dry rot affects tubers damaged by insects, mechanically, or infected with late blight. Therefore, it is clear how important during the growing season is the fight against soil, in particular, preventive measures aimed at combating such a common fungal disease as late blight.
Fighting dry rot (fusarium)
There are practically no chemical means to combat dry rot. But you can prevent the occurrence of this disease if you carefully check all tubers before planting and remove infected ones. Immediately before germination, they should be treated with a solution of copper sulfate (1-2 g per 10 liters of water) to prevent late blight.
They will help to avoid the appearance of this disease: healthy planting material, removal of sick plants from the garden, that is, those that begin to wither, systematic pest control, avoiding mechanical damage during harvesting potatoes, drying them before storing them, cleaning and disinfection, ventilation vegetable stores during winter storage. During the winter, it doesn’t hurt to sort through the potatoes several times, removing tubers with signs of disease.
Some gardeners, in order to avoid crop losses from potatoes, plant using innovative technologies in barrels, bags and under hay. But they soon become convinced that this does not save the tubers from bacteria, fungi and viruses that provoke a variety of ailments. They mercilessly attack healthy plants and their fruits in the open ground, and even in the cellar. Others often act as carriers of pathogens. Let's take a closer look at what potato diseases there are and measures to combat them.
Important! It is almost impossible to instantly cure planted tubers from diseases of any nature. This is due to the fact that most pathogens infect soil or seed. As a result, the fight against them should begin with processing and treating the fruits, as well as carefully preparing the bed for planting.
Bacterial diseases of potatoes
Bacterial diseases of potatoes are provoked by various kinds of microbes, which gradually spread from the tubers along the stems, infecting everything. It is extremely difficult to fight them, since the soil in which the root crop grows also needs disinfection. 
To cope with such a task, timely and competent sowing changes are necessary. Sometimes this will take years with alternate sowing of microorganism-resistant crops, such as wheat, corn, barley, in the infected area.
Brown bacterial rot
The disease occurs due to the activity of microorganisms Ralstonia solanacearum on potatoes. Its first manifestations are noticeable during the flowering period of the crop, when root crops begin to form. At this time, yellowing and wilting of the foliage is observed, it becomes wrinkled and lifeless, and the stems droop down and turn brown over time.
As pathogenic bacteria multiply, softening and putrefactive processes are observed in the lower root part of the stem. Splitting is clearly visible along the sprouts, and the infected veins acquire a brown, putrid color. 
If you cut the stem of a diseased plant, you will see dark brown fibers on the cut ring. When such a sprout is squeezed, a gray-white cloudy mucus will be released from it.
Botanists classify brown rot as a vascular disease of potato and note the death of bushes as a result of clogging of xylem veins with a dense gumy mass. There are cases when the disease manifests itself only as verticillium wilt and ring rot, in which there is no splitting of the shoots and mucous discharge is observed. 
The disease on tubers is expressed by a softened vascular ring and the appearance of brown putrefactive elements on the core. Often, decay processes begin already in storage facilities. They are accompanied by mucous discharge and an unpleasant odor. Such potatoes infect all neighboring tubers and completely rot.
Did you know? According to the International Finance Corporation, Ukrainians annually consume about 4 million tons of potatoes, despite the fact that the average annual yield of root crops is approximately 18 -19 million tons.
The country's leading agronomists draw the attention of farmers and landowners to the fact that the fight against bacterial diseases of potatoes should be aimed at comprehensive protection against the pathogens described above. At the heart of all such measures is the management of relations between internal and external populations.
This means that the plant must be protected throughout the entire growing period using different methods, including seed production and organizational and economic nuances, as well as the principles of combining crops.
When brown rot appears, crop rotation and the application of optimal fertilizers are key in the fight against it. It will be possible to plant potatoes on infected soil only after 5 years. Seed tubers must be carefully sorted and heated for 20 to 30 days. This will help to accurately detect unsuitable material. It will also be indicated by a 0.002% solution of succinic acid, which is used to treat the fruits for half an hour. 
If during planting it becomes necessary to cut root crops, the knife must be disinfected with formaldehyde or potassium permanganate. Healthy, for preventive purposes, before planting, they are treated with chemicals such as: “TMTD”, “Rizoplan”, “Baktofit”, “Polycarbocin”, repeating the treatment twice on seedlings until budding begins.
Varieties with increased resistance to microbes are well cultivated: “Resource”, “Ulyanovsky”, “Udacha”, “”. Control of bacterial diseases of potatoes includes regular inspection and removal of diseased plants.
Experts advise carrying out the first cleaning after the stems reach a height of 25 centimeters, the second during flowering, and the third several weeks before harvest. It is important to completely mow the tops during this period so that they have time to dry before harvesting the fruits. The entire crop should be thoroughly dried before storing in the cellar. Preparatory work is also needed in the storage facility.
For this purpose, remove all the remaining last year's and, disinfect with a 2% aqueous solution and treat the walls with extinguished. When entering the room, place a mat soaked in a 5% solution of copper sulfate.
Important! To safely preserve potato tubers in the cellar, for the first 20 days the room temperature should not be lower than +13 °C, and the air humidity should be kept at 90%. In the future, gradual cooling to 2 degrees is necessary.
Ring rot
Signs of ring rot are quite noticeable on potato tubers and biomass. They appear after flowering in the form of yellowing of thin shoots and curling of leaves. Affected specimens are difficult to pull out, even with general cell death. This happens due to the destruction of the stringy structure of roots and shoots. 
The disease begins from the roots, but its first symptoms can be noticed on the fruits only when they are cut. Yellow or brown rings on the edges of the core indicate the further development of putrefactive processes that will eventually destroy the entire fruit. When pressed, gray-yellow mucus flows from the affected areas.
If, when examining the seeds, you did not notice signs of rot and planted such a root crop, dwarf, poorly developed, thin shoots with small deformed leaves will grow from it. You should not expect a large harvest from such bushes. 
In most cases, bacterial diseases arise due to poor-quality planting material, or due to mechanical damage during harvesting root crops, transporting tubers in contaminated containers, as well as when storage rules are violated. Today there are no special pesticides against putrefactive diseases of nightshade crops. 
They are fought with quarantine methods, which, in addition to proper preparation of planting material and harvesting, include sowing changes for 3 years, selection of resistant varieties, potato fields with potassium preparations and systematic removal of diseased plants at the first signs of rot.
Did you know? Potato diseases destroy from 30 to 65% of the crop.
Wet rot
The disease begins from the core of the tubers and is often difficult to detect in the initial stages of development. Its root cause is bacteria or fungal pathogens that enter the root crop due to mechanical damage or are carried by pests. Based on these factors, it becomes clear why potatoes quickly rot from the inside. 
This process is expressed in the softening of the tubers and the spread of a strong stench. Rotten tissues are initially white, but later they turn brown, acquiring darker shades. By the way, the skin is affected when the inside is completely rotten. It happens that the surface of root vegetables becomes covered with dark dents, from which, when squeezed, a whitish starchy substance flows out.
If a root crop is exposed to cold conditions, its eyelids die and the process of rotting begins. Therefore, such tubers should not be protected; it is better to use them immediately, otherwise they will ruin the entire harvest. Farmers note that very often potatoes are affected by this disease in the cellar, especially when the product freezes or, conversely, is piled in a compartment and stored at temperatures above +4°C. 
The appearance of wet rot is also accompanied by high indoor humidity and poor ventilation. This is explained by a lack of oxygen, which entails a decrease in the immunity of potato fruits. You can, again, get rid of the problem through comprehensive measures. To do this, it is important to ensure that the soil in which the crop grows is not waterlogged and is well loosened. When storing in storage, select healthy tubers and dry them thoroughly. 
It is advisable to treat seed potatoes with the chemical “Maxim” before placing them in the cellar. And also protect the crop from various kinds of abrasions and cuts, take timely measures to combat pests. For the winter, place root vegetables, regardless of their purpose, in boxes or vegetable nets. In cases where you find foci of putrefaction, remove all tubers from the infected area and try to use them as soon as possible. Also strictly follow the rules for storing potatoes (we mentioned them above).
Did you know? Every year, Europeans collect about 35 tons of potatoes from 1 hectare, while Ukrainians collect only 15 tons. This difference arises as a result of the fact that 95% of the product is cultivated in small farms, which, of course, affects the quality of the tubers.
Mixed internal rot
This disease of potato tubers, like previous types of bacteriosis, occurs when root crops are wintered improperly and as a result of mechanical abrasions, blows, and cuts. Symptoms depend on the type of pathogens that have entered the tissue membranes of tubers. You can observe the signs of wet or ring rot, as well as dry rot, that we have already described. A gray, pink or brown slippery coating will certainly appear on the affected areas. 
The methods of combating these microbes are no different from those mentioned above. Your main task is to protect the crop from mechanical damage and provide the right conditions for its conservation. It is important to disinfect seed material before planting with any antibacterial and antifungal chemicals. Experienced summer residents recommend the drugs “Fludioxonil” and “Maxim”.
Blackleg
The disease begins to manifest itself as soon as favorable conditions arrive: increased dampness or prolonged hot weather. During drought, the course of the disease is sluggish and becomes chronic. The black leg is noticeable on both the underground and above-ground parts of the potato: the stem below turns black, the leaves turn yellow, the bush gradually fades, and the root crops begin to rot.
In the heat, within a week, the sprouts will begin to soften in the root zone, which usually fall due to their own weight. Infected specimens are easily pulled out, and mucous discharge is visible on stem sections. Tubers rot from the stolon areas, becoming covered with dark spots. A sure sign of the disease are putrefactive spots on the potatoes, darkened skin, cracks from which a stinking, pulling liquid is released. Such root vegetables are very light, which indicates the complete destruction of their insides by bacteria. 
It is possible to overcome blackleg by strictly following the rules of agricultural technology for growing potatoes, harvesting and storing them. In this aspect, crop rotation, planting high-quality seeds, timely loosening of the soil, phyto-cleaning and weed elimination, and disinfection of work equipment are important. Before planting, it is advisable to treat the tubers with preparations such as: “Maxim”, “Prestige”, “TMTD”.
Important! In order for seed potatoes to be well preserved until spring, they need to be greened in the fall.
Fungal diseases of potatoes
Botanists describe this group of potato diseases as the most serious and dangerous. The appearance of various fungi on the bushes or in the roots of potatoes necessarily entails disease.
They are often carried by harmful insects or caused by improper conditions for cultivating root crops. Let's look at brief characteristics of the most common fungal diseases and methods of combating them.
Common scab
The disease appears as a result of the activity of radiant fungi of the genus Streptomycetes. The precursors to their occurrence are low levels, limestones, sandy, sandy loam substrates and hot weather conditions. The pathogen enters the tubers through the stem. Infected fruits lose their taste and presentation. Small brown asymmetrical spots appear on the potatoes, which “cork” over time. 
As they develop, the sores merge together, and a coating is barely noticeable on freshly dug fruits. In the sun it quickly dries out and loses its mark. The core of such root vegetables, despite the ulcerative crust formed on the outside, does not change. For preventive and therapeutic measures, Candidate of Biological Sciences, Professor of NUBiP of Ukraine Ivan Markov advises observing crop rotation and rules for fertilizing potatoes.
According to the scientist, fresh, overdose and contribute to the development of pathogens. Therefore, it is important to introduce physiologically acidic substances at the rate of 60 kg per 1 ha, which are manganese sulfate and ammonium sulfate. Nitrogen stabilizers are also desirable. 
The harmfulness of scab is significantly reduced with proper dosage of calcium chloride, manganese, boron, copper, and cobalt. The required amount of the listed chemicals for a specific field can be calculated based on its agrochemical examination, which can only be done by a specialist.
If there is no possibility or means for laboratory tests, you can use the cheapest way to combat scab, focusing on disease-resistant potato varieties. Do not be afraid of fungal diseases “Bozhedar”, “Kosen 95”, “Chernigovskaya 98”, “Lugovskaya”, “Borodyanskaya pink”, “Vesta”, “Symphony”, “Vodograi”, “Velox”, “Gatchinskaya”, “Volovetskaya” ", "Zarevo", "Lybid", "Drevlyanka", "Serpanok", "Poran", "Rozara" and other varieties with thin skin of reddish tones. 
Also, each owner of a land plot should take care of the condition. To enrich it with useful elements, it makes sense to organize the plowing of green manure: lupine, clover or. Before burying, high-quality root crops selected for planting are treated with the preparations “Maxim”, “” and the growth regulator “Agat-25K”. After buds begin to form on the seedlings, the soil must be irrigated for 4 weeks, maintaining humidity at 75%.
Powdery scab
You can save potatoes from slime mold by regular sowing changes, planting high-quality seed, which should first be treated with fungicides (Maxim). The collection of root crops should be organized in dry, warm weather, observing the above rules for harvesting and storing tubers. In heavily contaminated areas, re-cultivation of the plant is possible only after 7 years.
Did you know? According to the Main State Plant Protection Inspectorate of Ukraine, in 1996 all potato plantings in household plots and agricultural enterprises in the Lviv region were affected by scab. This was a burst of intense fungal development. The latest data on tuber infestation is 17 – 24%.
Silver scab
By spring, they will show clear dents and a silvery sheen, which occurs as a result of complex processes of tissue exfoliation and access of oxygen to the formed cavities. In cases where mass infection occurs, the upper shells of the fruit are severely deformed, losing moisture. 
Comfortable conditions for the development of silver scab on potatoes are dampness in storage and too high a temperature. For example, 1 hour at +15 °C is enough for the formation of pathogenic spores. At +3 °C, mushrooms are not produced.
Methods of combating silver scab are traditional, as in previous cases of bacterial and fungal diseases. They differ only in the means for disinfecting seed potatoes. Agronomists advise using the following drugs: “Vivatak 200”, “”, “Maxim”, “Bontan”, “Titusim”, “Nitrafen”, “Tekto 45”. Dressing should be carried out immediately after harvesting root crops.
Black scab (rhizoctoniosis)
Compared to silver and common scab, rhizoctonia affects not only tubers, but the entire plant. The disease appears from substrates infected with pathogens, especially in the cold season. This distinguishes black scab from other species and poses a great threat to tubers planted in unheated soil. 
Young shoots of diseased crops are very sparse and depressed. Black, warty dots are noticeable on root vegetables, which peel off easily and can merge together.
On the stems, the disease manifests itself as brown sores, which in the root part are covered with a felt-like whitish coating, and on the roots - with rough spots. The massive spread of fungal spores can significantly reduce the yield and completely destroy it in the cellar. 
Its development is favored by cold and dampness. Therefore, for prevention, do not rush to plant potatoes, give the soil a chance to heat up and lose excess moisture. Inspect seed roots thoroughly, discarding contaminated samples.
Before planting, it is important to treat healthy tubers with Fundazol, Prestige or Maxim. Timely rotation of crops in the garden, elimination of tops before harvesting and plant residues after harvest, and fertilizing the soil exclusively with rotted organic matter are also important. 
Important! To increase productivity, potatoes should be renewed every 4 years, giving preference to elite, uninfected varieties of Dutch selection.
It is also important to germinate seed tubers in the sun, since sprouts that appear in the dark are the first to be affected by black scab. Agrochemists advise treating diseased bushes with potent drugs: Ditan M-45, Colfugo, Mancozeb, Fenoram Super.
Important! To save healthy potatoes from the scourge of black scab, it is recommended to organize early harvesting of the fruit.
Alternaria (dry spotting)
Alternaria potato blight is caused by fungi of the genus Alternaria, which become more active in dry and hot weather. You can notice traces of their vital activity starting from the flowering period of the plant. Symptoms are clearly expressed until the root crops are harvested. The disease manifests itself on leaves and sprouts; rarely, fungi infect tubers. You should be alerted by brown round or triangular spots that appear on the foliage or stems. 
Myceliums are easily transported by the wind, infecting new areas of the garden. This is the danger of Alternaria leaf disease on potato leaves. The fact of focal spraying of spores becomes clear. Their formation is facilitated by frequent changes in damp and dry weather, lack of moisture, unfavorable soil conditions, lack of potassium and nitrogen, and excess phosphorus.
Young fruits become infected with the fungus when they come into contact with the soil when dug up, while mature fruits become infected in the presence of abrasions and other mechanical damage. To destroy the fungi that cause dry spotting, the first step is to eliminate the primary sources in the soil. This is done by autumn plowing. In the future, beds with potatoes should be placed as far as possible from tomatoes, since Alternaria blight is dangerous for all nightshades. 
Seed tubers should be carefully examined, discarding specimens with a black or brown surface and slightly concave spots with uneven but clear edges. It is important to fertilize grown seedlings on time. As soon as you notice the first signs of the disease, immediately spray the planting with any fungicide. It is advisable to re-treat depending on the degree of infection and the long-term effect of the drug used. 
It is better to carry out disinfection in cool and damp, possibly rainy, weather. The percentage of the harvest you save depends on following the harvesting rules and storing it in the cellar. We have already mentioned above how to do this correctly. 
Some summer residents share their experience of planting varieties resistant to Alternaria. For example: “Lina”, “Nevskaya”, “Victory”, “Fairy Tale”, “Reserve”, “Lyubava”, “Skoroplodnaya”, “Volzhanka”, “Master”.
Did you know? Spanish farmers flatly refused to cultivate potatoes only because the root crops frightened superstitions with their human-like shapes.
Potato cancer
This is a fungal quarantine disease provoked by microbes, due to the activity of which damaged tubers are prohibited from being transported from their places of growth. Pathogenic microorganisms spread to root crops and the root system of the plant. The cancer appears as growths with a wavy structure that resembles cauliflower. 
Over time, these formations increase in size, change color, and move to the root zone of the stems and stems. At the final stage of development, they become black with a slippery, putrefactive surface. The spores are easily transferred to healthy fruits, especially during times of high soil moisture. They get into the ground with the help of working equipment, animals and manure, and remain viable for 4 years.
To get rid of the problem, pour kerosene, bleach or formaldehyde on infected fruits and tops and bury them to a depth of at least 1 meter. As an alternative, some gardeners suggest burning all affected plants, although surviving potatoes are not suitable for seed, as they are a potential carrier of pathogens. It is better to use such tubers for food purposes. 
Of course, the purchase of seed material is carried out exclusively in specialized centers. Before planting, inspect the tubers - cancerous spores may be hiding under the soil stuck to their surface. Organic and mineral fertilizers help free soils from infectious microbes. But it is important to ensure that the manure is thoroughly rotted. Chemical methods of combating cancer are only available under the supervision of a plant quarantine inspector. 
Important!Tubers that have grown in cancer-affected areas can be disinfected before sowing using a 1% Fundazol suspension.
Dry rot (fusarium)
The reasons why dry rot appears on potatoes are considered to be gross errors in agricultural technology and unfavorable soils, as well as mechanical damage and improper storage of tubers in winter. The symptoms of the disease clearly appear on the tubers in the form of dark swamp-brown spots, which over time transform into shallow dents. The skin on the affected areas is wrinkled, and a pubescent coating is noticeable. The picture is similar inside the fruit. 
With the development of fusarium, the bushes of the plant begin to wither, droop the stems and lose viability. If you cut off a diseased sprout, you can see a dark ring where the blade passes.
In order to destroy pathogenic dry rot fungi, it is recommended to strictly follow the rules of agricultural technology and storage of the harvested crop, plant only high-quality material, protect potatoes from blows and cuts when harvesting, and annually carry out pre-sowing treatment of tubers with fungicidal preparations (for example, “Maxim”, “Prestige”). 
Late blight
A fungal potato disease called late blight is considered the most insidious of the entire list of ailments. It affects the entire plant, but appears primarily on the foliage during budding of the bushes. You can recognize the appearance of late blight by the brown felt spots that form on the underside of the leaves and, growing, cover the plant with a solid brown carpet with a light white coating. On the stems, the disease is indicated by long dark stripes. Such a plant is not able to fully develop; rotting processes begin in it. 
Favorable conditions for the occurrence of late blight are high humidity after prolonged rains, warm weather and lack of good ventilation. When the weather returns and the soil dries out, the mushrooms stop functioning. But this does not mean your victory over the disease, since after the first rain the disease will begin to progress. 
To cure a crop, in addition to traditional methods, proper cultivation and storage of root crops, be sure to spray the bushes with a boron mixture, “Oxychom” or “Polychom” at the initial signs of late blight. Some summer residents resort to folk technologies for prevention, treating the foliage with garlic tincture six times. This process begins at the beginning of flowering and is repeated every 14 days.
The preparation of seed material is also important. In addition to germination and discarding everything unsuitable, the tubers should be treated with Fitosprorin, boric acid or copper sulfate. The soil in contaminated areas in spring and autumn is also treated with the above-mentioned preparations. 
Did you know? In the 17th century, the French introduced the fashion of decorating costumes and wigs with bouquets of potato flowers. In this country, the plant has long been cultivated as an ornamental.
Potato blight
Phoma pathogens penetrate the root crops, stems and sides of potatoes, exerting a detrimental effect on them. The sore appears as elongated, shapeless spots covered with brown dots. 
As they develop, fungal spores ring the shoots and prevent the culture from developing. Affected bushes differ from healthy ones by loss of foliage color saturation and lifelessness. If no measures are taken, the plant will die. On tubers, signs of phomosis are expressed in the form of ulcers that spread up to 6 cm. Over time, deep cavities appear in the affected areas. Such specimens stored in the cellar contribute to the proliferation of mycelium. They are also accompanied by post-harvest residues and weeds abandoned in the garden. 
Viral diseases of potatoes
Dangerous pathogens of potato viral diseases cause damage to yields gradually, resembling a time bomb. In the first years, their vital activity is almost unnoticeable, but later they destroy up to 50% of the fruits. Carriers of such diseases are Colorado potato beetles, aphids, cicadas and other pests. Infection during processing of root crops is also possible. Let's look at the most common potato diseases caused by viruses.
Ordinary mosaic
It is caused by several viruses at the same time. Favorable conditions for this are mechanical processing and the presence of harmful insects in the garden bed. Appears on young leaves as barely noticeable light green dots of asymmetrical shape. Over time, this mottling darkens and spreads to the entire bush. 
Wrinkled mosaic
When infected, the leaf tissues of the plant swell greatly, forming peculiar folds. They arise as a result of poor outflow of assimilated products. 3 years after cultivating infected potatoes, you will notice how the plants degenerate into dwarf plants with corrugated, underdeveloped foliage and very fragile stems. Such a bush is not able to set buds and bear fruit. He will finish his own a month earlier than healthy specimens.
Striped mosaic
For banded, the characteristic features are mosaic specks, which, first of all, appear on the lower and middle leaf plates. Later, black stripes and veins form on the affected areas. The leaves break easily, die quickly, and often hang lifelessly, exposing the stem before budding begins. The pathogen overwinters in root crops.
Gothic potato tubers
The disease occurs through the ingestion of the spindle veroid virus (VVVV), which is why it is also called “spinoid virus.” The harmful microbe manifests itself by deforming the tubers, deteriorating their taste and presentation. The foliage of diseased bushes is too elongated, very small, and does not develop properly. The edges of these leaves have an anthocyanin tint. Diseased plants grow poorly, are stunted, and the color of the tubers of red-skinned varieties is lost. At the same time, the root crops grow small in size with a spindle-shaped shape. 
Did you know? The most dangerous and widespread viruses are the PLPV and PVY viruses, which reduce the weight, quantity and starchiness of tubers, killing up to 80% of the crop.
Necrosis of potato tubers
The development of necrosis on potatoes begins with the entry of the Tobacco rattle virus into the soil and tubers, which reduces the starch content and leads to necrosis of the fruit. Characteristic features of the disease are small light specks that cover the leaves, deformation of inflorescences, dark necrotic spots on root crops, which often bend into bizarre stripes, arcs or rings. 
A very high prevalence of this virus is observed in sandy and swampy areas. Today there is no drug for viral potato diseases that would immediately solve the problem. However, in order not to lose the entire harvest, if symptoms of any of the listed viral infections are detected, immediately organize phytocleaning, repeating it periodically until all affected plants are removed.
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Dry rot of potatoes or fusarium is a common disease of fungal etiology. The danger of the disease lies in the fact that the causative agent of the disease (fungus) is quickly transmitted and can destroy up to 20% of the crop. Moreover, after this disease, potatoes are affected by a number of other diseases. What to do if you notice the first signs on tubers and what are the preventive measures?
The pathogen Fusarium oxysporum spreads very quickly and this is its danger. Fungal spores may initially enter the plant through wind or manure. The reasons for the development may be the following:
- Excessive manure content in the soil where potatoes grow;
- Inadequate care of the plantation - the beds are not weeded, the soil is not loosened;
- Waterlogged soil in hot weather promotes the proliferation of fungal spores;
- Mechanical damage to tubers by wireworms, mole crickets, nematodes, as well as during harvesting (cuts, incisions, etc.).
Once on one plant, the pathogen quickly spreads to nearby bushes. Not only potatoes are affected, but also other garden crops (tomatoes, peppers, strawberries, etc.)
From the soil, the pathogen enters the tubers through wounds and cracks. After harvesting, during transportation, fungal spores along with soil residues are transferred to storage. There, fungi continue to multiply intensively throughout the winter storage period. One undetected diseased tuber can infect nearby potatoes.
Signs of illness
From the affected soil, the fungus along with nutrients enters the plant stems. The tips of the leaves begin to turn pale and turn whitish. A pink coating appears on the stem. The mycelium grows and completely covers the stem, preventing further penetration of nutrients and moisture into the leaves. Deprived of nutrition, the growth of the bush slows down, the leaves and tops quickly wither and dry out.
During winter storage, 1-2 months after harvest, brown spots begin to appear on the tubers. Over time, the spots increase in size and become sunken. The affected areas dry out and become like dust, and voids form inside the tubers, with white fungus on the walls. Over time, the tuber turns into a hard and light ball.
Measures to combat dry rot of potatoes
Fusarium is an incurable potato disease; its spread can only be prevented.
Location on
- Check your potato plantings periodically. If you notice affected bushes, remove them immediately. It is best to burn the tops and root crops from this bush. Never place affected bushes in a compost heap!
- Take care of your plantings: weed and loosen the soil on time. This will prevent waterlogging of the soil and thickening of plantings. Remember that high humidity is ideal conditions for fungal growth.
- Immediately sort mechanically damaged potatoes (with a shovel, pitchfork or pests) to the side, try to use them primarily for food or livestock feed.
In the underground
We leave only healthy, undamaged tubers for storage, and before storing the crop in the cellar, the tubers are thoroughly dried and left under diffused light for 1-2 weeks (for example, in a barn), only after that can the potatoes be removed for storage in the basement.
During the winter, it is necessary to sort through the tubers several times to identify those affected by fusarium. If affected root crops are found, they are immediately removed and thrown away. To prevent or reduce the development of fungal diseases on potatoes, they are sprinkled with ordinary wood ash.
Prevention
If you plant potatoes collected from an infected area next year, a new round of the disease cannot be avoided.
Preventive measures are as follows.
Maintain potato crop rotation, especially if there have already been signs of this disease. It is advisable not to plant potatoes in this place for five years. Disinfect the soil.
Experienced gardeners recommend treating potatoes with antibacterial drugs before planting: Bactofit. It is useful to treat the planting material with solutions of copper sulfate, boric acid, and manganese before planting. In addition to disinfection, copper accelerates the formation of tubers, increases resistance to disease, boron improves taste, manganese accumulates starch and vitamin C in tubers.
In spring, the storage must be disinfected, ventilated, and dried. Before storing potatoes for winter storage, they are treated with the drug “Maxim”.
Besides,
- plant potato varieties that are resistant to fungal diseases;
- avoid excess organic fertilizers containing nitrogen;
- Weed the beds in time to remove weeds, loosen the soil, this will prevent the soil from being too moist, especially in rainy summers.
The causes and treatment of potato fusarium are also discussed in this video, watch it.
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Fusarium, or dry rot on potatoes, is the most common and dangerous disease. This disease is caused by fungal infections. If their spread is not prevented in time, more than half of the harvest can be lost.
Most gardeners believe that this happens due to improper storage of the crop. But experts say: during storage, only a few percent are allowed to become ill. If we consider the statistics, then most often the infection occurs in young potatoes that are just planted in the soil, and much less often during storage.
The disease is very dangerous due to its easy transmission with soil, and it can also remain on potatoes. As a result, healthy potatoes also become sick.
How to deal with fusarium
Pathogens live in various types of soil. Most often, they manifest themselves only under favorable conditions. Most of all they love soil that is rich in nitrogen and well fertilized with manure. Therefore, it is not recommended to apply organic fertilizers frequently to avoid problems.
Spores, which constantly sleep in the soil, begin to penetrate into the potatoes through wounds and cracks under favorable conditions. As a result, the disease begins to develop rapidly, gradually affecting the roots, leaves and stems. After flowering begins, Fusarium wilt can be observed in plants.
The leaves at the tips gradually lighten, whitish spots appear, and as a result, the stems are gradually affected. The outer part of the plant becomes covered with a pink coating, and then the inner part is affected. It can be noticed when cut; it changes color in the first stages of development. After this, the growth of the potato becomes slower, and eventually it withers.
Dry rot does not necessarily spread during the initial stages of potato development. Every experienced gardener can dig up a fairly healthy potato and leave it for storage. After a few months, the tubers become covered with small brown spots, then they increase in size and disappear. Subsequently, it becomes like a light but hard ball.
Unfortunately, the disease has no cure. You can take preventive measures to stop the spread, but those tubers that are already affected will gradually deteriorate. In addition to all this, the infection also brings with it other fungi, which deprive the gardener of a large share of the harvest.
If the disease is already present in the soil, then it requires careful treatment. You can plant green manure in the required place, as they perfectly nourish and cleanse the soil. It is advisable to treat it with the drug phytosporin.
Preventive measures
- With proper crop rotation, all infections are often eliminated.
- Do not apply large amounts of fertilizer to the soil.
- Tops and weeds should be removed from garden areas to avoid re-infestation.
- Before planting tubers, they should be treated.
- It is advisable to choose varieties that are more resistant to infections.
Dry rot is common, mainly the peak of infection and subsequent reduction in yield - during storage in the cellar. Although the infection still develops on the site during the rapid growth of potato stems. And the infection gets into the cellar with clods of earth. The disease appears a few days after the tubers are put into long-term storage. First, smoky spots with a brown tint appear on the outside of the potatoes, slightly pressed into the tuber. Gradually the spots increase in size. The skin wrinkles, the flesh becomes dry and rotten. Small round ash-white or pink “pads” form on the affected part of the potato. The core becomes brown.
In infected tubers, under the influence of enzymes, pathogens destroy the walls of potato cells. The tubers become soft, dry, voids are created in the middle, filled with fleecy white, yellowish mycelium. Gradually the disease spreads to the entire potato. This is facilitated by increased temperature and humidity. And in a dry cellar, infected potatoes turn into “mummies”, becoming light and hard. The disease reaches its maximum development in the middle and at the end of the preservation period.
The causative agent of potato dry rot is fungi, which often come from the soil and form spores on the surface of the tubers, that is, the main source of infection. Losses of potatoes during storage from dry rot reach catastrophic proportions. Of the entire harvest, half is lost. Even when planting infected tubers, there is a delay in plant growth and development, and partial death of stems at the initial stage.
First of all, adhere to the agricultural technology of planting potatoes. You can plant potatoes in the place where they were planted previously after 4 years. For seeds, select only healthy tubers without any visible damage or contamination. Do not use fresh manure during planting.
If tubers are severely infested with dry rot, spray with fungicidal preparations.
Also, when harvesting potatoes, avoid mechanical damage and injury to the tubers. Before storing potatoes, be sure to adhere to the curing period, that is, keep the harvested crop at a temperature of 10 - 14 degrees for about 3 weeks.