Potatoes grow well in almost any climatic conditions. It tolerates acidic soil, but the harvest rises significantly after liming. A large amount of moisture and light are, in fact, the only conditions for the growth of potatoes. But even in ideal conditions, the culture is under the threat of infection by fungi, viruses and bacteria. Here we consider the most basic problems and universal solutions that will help to cope not only with the examples presented, but also to prevent many other similar diseases. Despite the fact that potato varieties resistant to late blight, nematode or scab are derived, diseases and pests still continue to destroy the crop. But for every enemy there is a weapon.
The wireworm is a larva of a click beetle. It is a small gray insect with a length of 12-15 mm. It got its name because it makes a clicking sound, turning from back to paws. One female lays from 50 to 200 eggs in the spring, from which the ill-fated wireworm is born. The larvae are able to destroy the whole crop, so first of all it is necessary to protect it from the beetles themselves.
There are three ways that are suitable for combating this parasite:
- A peeled potato is strung on a stick and buried in the ground for about 7 centimeters. It is better to make several such potatoes in order to cover a large area. The larvae of the click beetle will gather on it, and in four days it will be possible to dig it out. Destroy pests can be using boiling water or fire.
- When planting potatoes, pour sunflower oil with finely chopped chicken eggshell into the ground. Such a solution will kill the wireworm before it reaches the potato. This method will help the harvest not only from the wireworm, many other earthen insects die in such a solution, for example, a bear.
- Two weeks before planting, bury corn grains in the ground - about 2-3 nests per square meter. Wireworm attracts not only potatoes, the larvae will be happy to gather around the grains. When the corn germinates, you can dig it out, harvest the larvae and burn them, or pour boiling water over it.
Late blight (phytophthora) is not only the cause of the loss of the tomato crop, but also the most common potato disease, and the control of them is important for all farmers, regardless of the crop. For potatoes, late blight is especially destructive, as it can infect the entire field within two weeks. Losses reach 70% yield. Late blight spreads through fungal spores, which allows it to quickly move underground and infect tubers.
In the first days of the appearance of late blight is manifested in darkening on the leaves. Also on the underside of the sheet appears white bloom. These are germinating fungal spores. They fall down, infecting the roots and fruits of potatoes. A little later on the tubers appear brown spots.
Fight against late blight
Dangerous fungus requires serious integrated measures. So, it is necessary:
- Use potato varieties resistant to late blight.
- Select healthy tubers for planting.
- Treat tubers with fungicidal agents.
- Spud when needed.
- Increase doses of phosphate-potassium fertilizer.
- Apply fertilizers containing copper, or spraying a solution of copper sulphate.
- Remove tops before harvesting.
The nematode disease is caused not by a virus or a bacterium, but by a microscopic worm that parasitizes potatoes. It is easy to check for the presence of a pest: if the bushes wither, and their small leaves are uneven or even pale in color, there is a nematode. Shrubs become frail, and small roots. In July, small balls will appear on these spines (from half a millimeter) with small processes. These are female nematodes; if they develop further, they will turn into cysts, which remain in the ground for another 15 years. There are about 600 worm eggs in the cysts.
After the appearance of nematodes, it is necessary to wait at least 6 years before sowing the area again. However, there are other ways.
Potatoes of early or unstable to the nematode variety are placed in boxes in one layer, powdered with peat chips and planted after 20 days. After 50 days, the crop is harvested, and the plot is thoroughly cleaned of the tops. The plot itself is sown with legumes or corn. This will clear the soil of the worm by about 70%.
If you sow rye on the plot, it will also significantly reduce the parasite population.
It is worth noting that the potato attracts the nematode more than other plants.
The most common potato disease after late blight is scab. It degrades the quality and appearance of tubers and reduces the level of starch in them by almost 30%. Productivity is almost halved. During storage, infected tubers are highly susceptible to rot.
The scab is caused by mold - a radiant mushroom. It penetrates the potato lentils and mechanical damage, forming on the surface of the sores, which merge together and form a cork tissue. White bloom appears on the tubers - the mycelium of the radiant fungus. When dried, they disappear, and the flesh is almost unchanged.
There are five types of lesions:
- Flat. It affects the skin of young tubers, from which the skin hardens.
- Mesh. Covers tubers with a variety of netted grooves.
- Convex. Appears in the form of grooves, which later become covered with growths.
- Deep. Deep ulcers of various shapes, surrounded by peel breaks. Visible when harvesting potatoes.
- Convex-deep. The combination of two types of damage. Overgrowth with deep ulcers and ruptures of the skin.
Scab pathogens are stored in the ground for several years. They are not affected by negative climatic factors, they persist even in droughts and at temperatures of -30 ° C. Hot and dry weather during flowering only contributes to infection.
The source of infection is always the soil. Tubers can not infect each other, so they can be stored together.
The scab is not easy to notice right away, so it is impossible to save already infected potatoes. Other types of diseases and pests even “warn” about their appearance, but it is better to deal with all in advance using the following procedures:
- Compliance with crop rotation.
- Cultivation on the site sideral cultures.
- Use healthy fruit for sowing.
- The use of acidic fertilizers.
- Thorough preparation.
- The use of resistant varieties.
- Regular watering during the growing season.
The disease has spread everywhere where potatoes are grown. Diseases and treatment of solanaceous plants are still more studied in the southern regions, since in the south there are ideal conditions for the growth and spread of fungi, which tolerate alternariosis.
Depending on the period of the disease can manifest itself in different ways. Infection begins after rain or thick dew. Spores of the fungus fall into the cracks, mechanical damage or natural grooves. Acid begins to be released, from which the stalks rot and die. At low temperatures, development is insignificant, but in hot weather, the disease has a dangerous effect on yield. Incubation lasts up to a week.
The first signs are visible on small plants, up to 20 cm high. Later on the leaves appear dark brown spots. With good development conditions, they can be seen on the third day. Smoky-gray conidia appear a little later. Damaged plant parts are fragile and soft.
On the tubers, extruded dark spots of rot appear, sometimes even with wrinkles. Eventually, the tubers begin to rot completely, drying out and blackening.
In the southern regions, potato disease and control require special attention. There are three ways to protect the crop:
- Agrotechnical. Use only a healthy, disease-resistant planting material, observe crop rotation and do not forget that early potato varieties are most susceptible to infection. Seed material must be heated for the first two weeks at a temperature of up to 20 ° C. During storage, make sure that there are no sick tubers. Alternaria can be transmitted from one fetus to another. Remove tops in a timely manner, it is better to conduct desiccation using special means.
- Biological. Spray the tubers before planting Integral, Baktofit, or Planriz.
- Chemical. Preparations "Ridomil Gold We", "VDG" and "Bravo" will relieve you of all existing mushrooms, depriving them of comfortable conditions. Before planting, you can also spray potatoes with the Maxim fungicide solution.
Diseases of potatoes and the fight against them, as well as other pests, always require special attention. The harvest depends on how well all the requirements are met. The article is not for nothing that photos of potato diseases are given, because the enemy must be known in person.
How to distinguish and recognize?
The causative agent is the lower fungus Oomycete. The incubation stage lasts from 3 to 15 days, so the first signs of damage appear very quickly. Zoospores are stored in the soil and seed. With wind and rain, they spread throughout the potato field. For sprouting stems rise to the tops and down into the tubers with moisture. Conditions for progressive infection:
- temperature of 20 degrees
- humidity 90%.
The main manifestations of brown rot:
- brown leaves on the leaves, quickly spreading along the bush,
- on the back of the sheet - white bloom containing spores,
- a little later, the leaves completely darken, curl up and dry out,
- tubers are covered with lead-gray indented seals,
- spots penetrate deep into the form of stains.
Prevention of disease, the top 12 rules
Prevention comes down to the following tips:
- The soil should be light, non-clayey, drained and even.
- The plot is lit and ventilated.
- The varieties are resistant and strong.
- Tubers are healthy.
- Landing to do early.
- Harvest in dry weather.
- Rotations every three years.
- Tubers for storage dry well.
- Sowing sideratov for the winter is mandatory - mustard, radish, oats, wheat.
- In early spring, they are buried in the ground for rotting.
- Fertilizer of the earth with phosphate and potash preparations.
- Treatment of tubers before planting with fungicides - Agat-25K, Immunocytophate.
Important! When making the autumn bulkhead of tubers, patients just need to burn.
Breeders constantly bring new resistant varieties to the pathogen. Here are the most popular ones:
This does not mean that these representatives will not become infected with the fungus. But the disease in them will proceed in the mildest form.
Late blight is not treated, but it is necessary to fight to contain it. The first spraying is carried out at a height of 25 cm tops. For this, Bordeaux mixture, copper sulphate, copper sulphate, and manganese solution are widely used. When there is a risk of late blight, for the treatment of plants using special tools:
- Epin, treated before flowering,
- drugs that increase the protective forces of the plant: Silk, Krezacin, Immunocytophate,
- contact antifungal agents - Efal, Ditan, copper oxychloride,
- Ridomild Gold MC, Ridomil MC, Oxy. These fungicides are sprayed during the height of the disease. But only before flowering,
- Bravo, Alufit, good to use after flowering.
Who causes the disease, deceit pathogen
The causative agent of the disease is the synobitrium endobioticum. Fungus, parasitizing on the nightshade, and quickly leading to their death. It damages the tubers, without touching the roots. The fungus does not withstand high temperatures or frost. Where the soil freezes to -12 or heats up to +30, there is no cancer. The pathogen overwinters in zoosporangia with 300 spores each. Stored in this form, it can up to 30 years. For germination you need:
The pathogen moves through the capillaries of the soil. He has 12 hours to implement. Once in the plant cells, it produces toxins. These substances cause the rapid growth of neighboring cells - a tumor-like formation in the form of growth is formed.
- the owner himself - his shoes and clothes,
- polluted garden supplies,
- humus of animals that ate infected potatoes,
- soil worms,
- garden pests
- diseased plants.
Manifestations of the disease
Cancer lesion symptoms are specific, they are difficult to confuse with something. Key features:
- tubers, less often stolons and stalks are affected,
- on the potatoes next to the eyes grow bumps,
- growths are formed from tubercles.
There are three types of cancer:
- Sheet-shaped. Overgrowths are like leaves.
- Scaby. On the peel many small growths.
- Corrugated. The surface is knobby and wrinkled,
To prevent the disease you need:
- Crop rotation every three years.
- Tomatoes and peppers to plant away.
- Acquire planting tubers in proven nurseries.
- When a cancer outbreak occurs nearby, acquire resistant varieties.
Important! Experts suggest that sick potatoes are a threat to human health. Its tubers should not be used for food.
- early - Forget-me-not, Spring, Anosta, Aksu,
- medium - Condor, Nevsky, Sante, Andretta,
- later - Cardinal, Lasunak.
- 0.5% Benomyl solution is used to disinfect the planting material. To do this, for 30 minutes the seeds and tubers are immersed in the solution.
- 1% Fundazol process tubers for half an hour on the eve of disembarkation.
- To destroy the fungus in the soil using a 2% solution of Nitrofen. At 1m2 20 l. For 3 years in this area you can not plant anything.
How to recognize Alternaria?
The disease affects the middle and late varieties. Signs appear two weeks before flowering. Symptoms of Alternaria:
- brown dry spots on leaves up to 3 cm,
- the shape is rounded, there are spherical rings,
- the disease starts from below, and rises up,
- leaves are affected from the center to the periphery,
- after 20 days on the stains there is a raid with spores,
- with stems everything happens exactly the same
- in-depth spots appear on the tubers.
Treatment is performed when symptoms are detected as quickly as possible. Primary spraying is carried out when the tops begin to close. The decision to conduct the following depends on the course of the disease. During the season, make no more than 4 treatments. For spraying used chemicals. Their use is regulated by the manufacturer. It:
To prevent Alternaria, you must:
- Destruction of infected potato residues.
- Deep plowing.
- Crop rotation every 3 years.
- Use sustainable varieties: Master, Reserve, Victory, Blue, Resource.
- Seed material soaked in biological products - Agat-25, Baktofit, Integral.
- In time to reject diseased tubers.
Fomoz, button rot
The disease is among the most dangerous and formidable of all potato pathologies. This disease has many names - gangrene, fomoznaya and button rot. Huge damage is applied to potatoes with fomoz. The plant rots and dies, the tubers do not ripen. If the wind blows and it rains, the disease becomes epidemic. In storage stores up to 25% of the potato crop.
An imperfect strain of pathogen fungi belongs to the genus Thomas. Different strains of pathogens affect the stems and root system. Spores hide in special formations of pycnidae that form on the peel of a tuber. Favorable conditions for the defeat are:
Method of distribution - airborne.
How does fomoz manifest?
The first signs of infection are visible in the vegetation stage. The defeat of the tubers is determined by digging the crop. During storage, the fomoz continues to progress, until April, the potato is completely rotted.
- dark elongated spots appear at the base of the petioles,
- they surround the stem annularly,
- on closer inspection, brown pycnids are visible,
- infected stems quickly rot,
- the infection gets into the soil and into the tubers through the eyes, wounds on the peel,
- stolons are infected, and through them the whole potato.
Ocellar form of fomoz is distinguished. The pathogen is entered through the eyes. Putrid dents are quickly formed. Potatoes are massively dying.
There is another form of gangrene - necrosis of the epidermis. On a peel shallow ulcers, no more than 5 mm are noticeable. They can completely cover the skin or partially. The color of the affected tissue varies from pink, yellow to brown.
The disease has 3 stages:
- Initial. On tubers appear circles, similar to the hole left by a button. Hence the name - button rot. The diseased tissues on the incision are separated by a strip, contain spores, and have a brown color.
- The height of the disease. In the tubers appear cavities covered with a layer of mushroom mycelium. Sick tissues turn black.
- The final one. Tubers wither, dead tissues and pycnidia remain inside.
The disease belongs to fungal diseases. The causative agent affects mainly tubers and stolons. Potato becomes tasteless, loses 30% of starch. Experts identify 4 types of the disease:
- Black - rizoktonioz.
Pathogens are stored in tubers, soil, potato debris. Prefer alkaline dry ground. Penetrate cracks in the peel. Potatoes are well preserved.
Manifestations - ulcers of various shapes cover the rind of the tuber, there are cracks.
Наиболее часто встречающийся вид болезни. Патоген имеет вид куска слизи, медленно перемещающегося. Болеют клубни, столоны. Potatoes are stored poorly - quickly rot. The source of infection can be contaminated soil, tubers, animal manure, eating a diseased potato. The development of scab contributes to heavy ground, abundance of moisture, heat up to 18 degrees.
- whitish growths on the roots
- there are many warts on the peel,
- the shape, size, relief of the spots are different,
- affected areas open, forming ulcers,
- disputes persist,
- tubers rot quickly.
Plants grown on sandy and loam plants are ill. Optimum conditions - humidity 90%, temperature about 20 degrees. Affected potatoes are stored well, do not rot, only slightly dries out.
Signs by which pathology can be distinguished:
- the rind of the potato looks wrinkled,
- the color of the spots is like silver paint,
- during storage stains may darken, grow brown, press in,
- under the shell, when the cut is visible black formation.
It is considered one of the most dangerous fungal diseases. It occurs at any stage of development. Optimum conditions - high humidity and heat. If the spring is cold and damp, the bushes are massively dying. Crop losses reach 25%.
What are the main symptoms to help recognize rhizoctoniosis?
- Black spots on potatoes.
- They do not wash off, do not scrape and not scraped.
- The stems are low and quickly fade in the sun.
- The leaves are twisted.
- The stem has a white leg.
Viral diseases: what are and how to fight?
Viral diseases are the main reason for decreasing the level of yield, since plants affected by such a contagion are lagging behind, blooming rather poorly, and as a result, the tubers are small and tasteless. There are several most common viral diseases in our country:
- Mottled mosaic, which is manifested in the appearance of light and dark spots on the leaves of plants.
- Striped mosaic - it is expressed in the death of veins on sheets, petioles and stems. After this, brown small spots begin to appear, which are especially noticeable on the surface of the leaves. If you do not take care of the plants in time and do not start a fight, your plants will simply wither.
- Often there is a spindle tuber. The disease is expressed in the delayed growth of plants, the torsion of the leaves, the tubers take a spindle shape.
Whatever viral disease catches up potatoes, there are no optimal methods to combat them. But to prevent the disease is quite simple, first of all, choose a healthy seed.
In order to prevent the harvest should be harvested in time and remove the tops, because it is through the aerial part that viruses penetrate.
A nematode is exactly that type of pest that needs to be fought especially actively. It is recommended to grow resistant varieties, carefully cultivate the soil, properly prepare planting material. You can use chemicals, or resort to the radical method - an infected shrub is removed along with the roots and burned.
Nematode gives offspring that can survive in harsh climatic conditions. Therefore, the infected area is subjected to disinfection, planted on it exposed to the pest of culture is prohibited for at least four years.