Content
Diseases of potato tops damage the crop and can cause plant death. Such lesions have different origins. Diseases are caused by fungi, viruses and bacteria. Depending on the symptoms, the treatment method is chosen.
Causes of potato diseases
Potato diseases can be diagnosed by changes in the condition of the tops. Usually their pathogens are mixed from the stems to the root system.
There are various reasons why potato diseases appear:
- low resistance of varieties to pathogens;
- the presence of a fungus in the soil that affects potatoes, tomatoes and other nightshade crops;
- high humidity and hot weather, which provoke the spread of fungus;
- lack of nutrients;
- improper fertilization and watering.
Fungal diseases
Fungal diseases spread harmful spores. They can be stored on equipment, in planting material, or old tops. The development of fungal diseases occurs at high humidity and high ambient temperatures.The main diseases of potato tops, photos, descriptions and treatment are given below.
Late blight
One of the most common and dangerous potato diseases is late blight. The disease spreads to stems, tops and roots. Symptoms of late blight appear in the second half of the growing season, when plants begin to flower.
Late blight has the following symptoms:
- Weeping spots appear on the lower leaves, which become brown over time;
- a white coating forms on the back side of the sheet;
- the appearance of hard gray spots on potato tubers.
A set of measures will help prevent late blight. All of them are aimed at strengthening plant immunity and destroying the source of the disease:
- use of potash fertilizers;
- feeding potatoes with solutions based on boron, manganese and copper;
- spraying seedlings with a 0.2% solution copper sulfate.
When the first signs of the disease appear, chemical protective agents are used:
- Spraying with Bordeaux mixture 1% concentration. To prepare it, two solutions are prepared: based on copper sulfate and quicklime. Potatoes are processed every week.
- Use of chemicals. Oxychom is an effective remedy against late blight. A bucket of water requires 20 g of the substance. The resulting solution is used to spray potatoes.
Black scab
The disease manifests itself as a black coating on the tubers, which is easily removed. Black scab is dangerous because it damages potatoes intended for planting next year.
The disease actively develops when potatoes are planted early, when there is high humidity and low temperatures. As a result, tuber germination slows down. When exposed to black scab, the seedlings become brown and ulcers appear on them.
To protect potatoes from this disease, planting sites are constantly changed. Potatoes should be planted only after the soil has warmed up well. The crop is harvested only in dry weather to avoid the spread of the fungus.
If a disease is detected, the tubers will have to be eliminated. The remaining root vegetables are treated with the following preparations:
- "Ditan M-45". Add 0.2 kg of the substance to a bucket of water, after which the tubers are placed in the solution.
- Boric acid. A 1% solution is prepared for processing.
Potato cancer
One of the most dangerous potato diseases is cancer. The lesion covers the tubers on which growths appear. Today, about 18 varieties of fungus are known that can cause potato cancer.
The causative agents of the disease affect different types of plants that belong to the nightshade family. A favorable environment for the spread of the disease is a temperature of about 20 degrees and high humidity. The pathogen remains viable for 30 years.
Cancer looks like growths that gradually grow and turn brown. As a result, the tuber is destroyed. The causative agent of the disease spreads during the potato growing season due to the formation of zoospores. The fungus is transferred to the soil with root crops, seedlings, and persists on garden tools and equipment.
Quarantine measures help prevent the development of the disease. The material for planting is sorted out, after which the affected specimens are eliminated.
The soil is disinfected with a 2% Nitrafen solution. For every square meter, 20 liters of solution is required. Treatment is carried out according to instructions in early spring using protective equipment.
Dry rot
The disease is common in the southern and eastern regions. Dry rot can lead to the loss of 40% of the crop.
Its causative agent is a fungus that attacks potato tubers. The spread of the fungus occurs through infected roots, soil and plant debris.
Signs of the disease are:
- the top of the bush brightens and gradually fades;
- the lower part of the stem becomes brown;
- with high humidity, an orange or pinkish coating is found on the stem;
- when cutting the stem, the vessels of the plant are visible;
- Over time, the potato bush wilts.
On the affected tubers, grayish depressed spots spread, under which the pulp dries out. In the root crop, voids appear in which the mycelium is located. Such tubers have difficulty germinating and form weak bushes.
There is no universal cure for dry rot. To prevent the disease, planting material is treated with Fitosporin. To prevent the disease from spreading during potato storage, the tubers are placed for some time in a solution of the Maxim KS drug.
Alternaria blight
The spread of Alternaria blight is observed on potato stems, tops and tubers.The disease leads to a 30% reduction in yield. Usually the disease is diagnosed on mid- and late-ripening varieties.
Alternaria has a number of symptoms:
- two weeks before flowering, large brown or brown spots appear on the leaves;
- As the disease progresses, the spots merge, potato tops turn yellow and dies;
- the stems have elongated spots.
The disease is spread by insects and raindrops. When the temperature rises to 26 degrees and high humidity, the active development of fungus on potatoes begins. Weakened plants with low immunity are especially susceptible to Alternaria.
To combat the lesion, solutions of chemicals are used: “Kuproksat”, “Profit”, “Novozri”, “Metaxil”, “Ridomil”. For preventive purposes, planting material is treated.
Macrosporiasis
Macrosporiasis is a fungal disease that affects nightshade crops. It is determined by the following signs that appear before flowering begins:
- small spots of gray, brown or brown color on potato tops;
- spread of a faint black coating;
- With a lack of moisture, the tops gradually dry out.
The disease can also appear at later stages of potato development. In this case, the lesions are located along the edges of the leaf and are round in shape. With a high degree of disease development, the leaves curl into a tube.
The following methods help to get rid of the disease:
- Bordeaux mixture (during the growing season, a 1% solution is prepared, after harvesting, treatment is carried out with a 3% mixture);
- polycarbocin (the working solution is prepared from 0.4 kg of the drug per liter of water and is applied during budding, then the procedure is repeated after two weeks);
- potassium permanganate (10 g of the substance is taken per liter of water, after which the potato tops are sprayed).
Viral diseases
Diseases of a viral nature cause irreversible changes in plant organisms. Their impact leads to a change in color and deformation of the tops. As a result, the potatoes have a depressed appearance and develop slowly.
The infection persists in the tubers and has no external manifestations. After planting infected material, the potato development process is disrupted. Distributors of the virus are bedbugs, aphids, leafhoppers and other insects.
Diseases can be avoided by following preventive measures. This includes the selection of high-quality planting material, preventive treatment of tubers and soil.
Listed below are viral diseases of potato tops with photos and descriptions.
Striped mosaic
The disease affects the above-ground parts of potatoes and is diagnosed by the presence of mosaic spots or stripes. Dark brown stripes appear on the veins on the back of the leaf. As a result, the stems become more fragile.
In the last stages of the growing season, the lower leaves of the potato dry out and fall off. When tubers are damaged, bulges and rings appear on them.
Banded mosaic is spread by aphids. The disease spreads to healthy tubers through mechanical damage.
Wrinkled mosaic
Wrinkle-type mosaic appears as swelling of the leaf between the veins.As a result, the leaves become corrugated.
The disease is difficult to diagnose in the first year, since its manifestations are little noticeable externally. After three years, the wrinkled mosaic results in slow plant development. This is determined by the height of the plants, which does not reach the norm.
When affected by mosaic, potatoes have small, wrinkled leaves that break easily. Such potatoes do not bloom, and their growing season is shortened by 4 weeks compared to healthy plants.
Curling leaves
Potato leaves curl under the influence of a virus that spreads in the seed material. During the growing season, infection occurs through insects: aphids and bedbugs.
Viral infection leads to a decrease in yield. Losses can be up to 70%. At high soil and air temperatures, the spread of the disease accelerates. Lack of watering also causes curled leaves in potatoes.
The disease is determined by the following characteristics:
- the plant acquires a pale green color;
- the tops become yellow, and the back of the leaf turns pink;
- first, the lower leaves of the potato curl, after which the disease spreads to the top of the bush;
- twisting occurs along the central vein in the shape of a boat;
- the sheet plate becomes rigid and breaks upon any external contact.
The process of potato infection can take up to two years. If curled leaves are detected, the plant is removed. Torsion cannot be treated, so increased attention is paid to the selection of planting material, periodic inspection of plantings, and pest control.
Before planting, tubers are disinfected using special preparations.This will kill the virus before it spreads to the potatoes.
Mottling
In the presence of this disease, mosaic-shaped spots appear on young leaves. They are light green in color and irregular in shape. As the disease progresses, dark brown spots are diagnosed on the tops.
The causative agent of mottling is a virus that is transmitted through the interaction of healthy potato bushes with affected leaves. This occurs through direct contact, damage caused by garden tools, or insects.
To prevent mottling, the soil is treated with herbal preparations. The first procedure is carried out after the first potato shoots appear. Then the treatment is repeated twice during the season.
Needs to be eliminated on site weeds, which also attract the virus. Increased attention is paid to the fight against aphids, which serve as carriers of infection.
Gothic tubers
This disease is of viral origin and leads to stretching of potato tubers. As a result, they acquire a cylindrical shape, reminiscent of a spindle.
The virus affects potatoes at any stage of development. Upon contact with infected tops, the disease spreads to the leaves and stems of the plant. The pathogen can live in the soil and is carried by bedbugs, Colorado potato beetles and grasshoppers.
Gothic can be identified by a number of characteristics:
- small leaves located at an acute angle relative to the stem;
- potato shoots do not branch;
- after flowering the tops turn yellow;
- in the second year, the affected plants do not produce inflorescences;
- potatoes contain an increased number of eyes;
- During drought, the tubers crack and become stained.
Gothic appears on any potato varieties. To prevent disease, oats and rye are planted on the plot after harvesting. The root system of these plants has the ability to disinfect the soil.
The virus can be stored on gardening equipment for up to two years. In soil, the pathogen remains viable for two months.
Bacterial diseases
Bacterial diseases may not appear for a long time. Harmful bacteria are usually contained in planting material that looks completely healthy outwardly. The disease is detected after potato planting, when disturbances occur during its development.
Blackleg
The disease develops on potato seedlings, the tops of which begin to wither. As a result, the leaves turn yellow and gradually droop. The potato stem turns black and is easily pulled out of the ground.
When humidity is high, blackleg also spreads to adult plants. When the stem rots, its tissue becomes dark green, cavities appear on it, and blood vessels turn black. The spreader of the disease moves to formed potato tubers.
When affected by blackleg, up to 80% of the crop is lost. Infected root crops cannot be stored because they quickly rot. If the disease has spread to healthy tubers, weakened plants are formed as a result.
The infection spreads at low temperatures and high humidity. If unfavorable symptoms are detected, the plants are removed from the site.Healthy plants are treated with a solution of potassium permanganate at a concentration of 3%. Potato stems can be sprinkled with ash.
Ring rot
Disease Ring rot proceeds quite slowly. The following symptoms are observed:
- the tops turn yellow;
- the stems gradually wither and fall to the ground.
Ring rot continues until the period harvesting potatoes. The development of the disease is provoked by drought and hot weather. When the tuber is damaged, the vascular ring turns yellow, softens and rots.
When a disease is detected, the affected bushes are dug up and burned. Warming up the seed will help prevent ring rot. The disease manifests itself when the temperature rises to 18 degrees. Soft potato tubers on which black depressions have appeared are not used for planting.
The correct choice of planting site and the use of high-quality planting material will allow you to avoid ring rot. Fertilizers based on nitrogen and potassium are required to help strengthen the immunity of potatoes.
Prevention measures
With timely implementation of preventive measures, the likelihood of the spread of diseases can be significantly reduced.
Preventative measures for potato diseases are as follows:
- Selection of varieties resistant to pathogens. It is best to choose varieties bred specifically for your region. They take into account the composition of the soil and the climatic conditions of the area.
- If signs of disease are detected, curly leaves and other affected parts should be destroyed by burning.
- Compliance with crop rotation rules.It is recommended to plant potatoes in places where cabbage, pumpkin, cucumbers, and legumes previously grew. It is prohibited to plant in beds where sunflowers and nightshade crops previously grew.
- Treatment of tubers before planting. The use of special preparations makes it possible to destroy the sources of the disease living on planting material. Fitosporin, Prestige or Maxim are suitable for these purposes. First, a working solution is prepared according to the proportions indicated on the package. Potato tubers are dipped into it for 15 minutes.
- Timely care of plantings. This includes hilling the plants, watering and fertilizing.
Conclusion
The development of diseases can be detected by the external condition of the potato: the leaves begin to curl and turn yellow, and spots appear on them. As a result, plant development slows down and crops are lost. Following agricultural practices and choosing high-quality tubers for planting will help protect potato plantations from diseases. Potatoes need to be processed periodically to prevent diseases.
This year, many potato bushes died - first, near the ground, the stem became soft and watery, then the whole bush dried up... It looks like someone has chewed through the stem. In such bushes the potatoes are small or not at all. Although initially the bush was large.
Immediately after the potatoes sprouted (about two weeks), bright yellow leaves appeared on some bushes. I can't figure out what it is.
Hello! Today, July 10, 2019 I noticed the collapsed potato bushes... several bushes with yellowed leaves at the bottom and are already preparing to fall apart (so to speak)... I read about potato diseases, but nothing fits this...
Good afternoon
Most likely, those few potato bushes whose leaves have begun to turn yellow are early ripening. Potato bushes begin to decay 2-3 weeks before ripening. Perhaps you just happened to come across potatoes of a different variety when planting. There is no need to panic or worry.
A neighbor gave me 2 potatoes for divorce. The potatoes did not sprout for a long time. Then twisted shoots appeared, like ferns in spring. Again they take a long time to unfold, but there are no leaves, but as if there are only veins. So far everything is fine with my potatoes. Have I damaged my plantings? Thank you.
Good afternoon
It is unlikely that you have done any harm to your potato plantings. In this case, you need to wait a little to see what happens next. Observe the new potato bushes for at least 2-3 weeks. And if possible, ask a few questions to the neighbor who shared the tubers with you. Find out what kind of potato variety it is, how it grows on her site, and whether there are any differences. You will always have time to dig.
We wish you high harvests!
Hello! Explain what kind of disease this potato has - the upper leaves begin to shrink, their edges are raspberry-colored, and then the whole bush withers?
What is the reason, the tops of the potatoes turn black after flowering, first the leaf along the edge begins to turn black, then the tops turn black with black dots and dry out, we treat them with fungicides regularly.?
Hello! Your potatoes have clearly been affected by late blight. All nightshade crops suffer from this pathogenic fungus. You did not write what fungicides you treated the crop with - not all of them are capable of destroying late blight. In addition, even the “right” drugs will not always help - the fungus quickly adapts.
Copper-containing fungicides cope best with it. They will need to treat not only the plants, but also the soil after harvesting the potatoes. In the spring, before planting, the procedure should be repeated - the spores live and overwinter in the ground.
Nightshade crops cannot be planted in one place for two years in a row. You should not change their places, namely: plant potatoes where tomatoes, peppers or eggplants grew last year. The crops have only one pest, and it won’t go away. Unfortunately, this does not always work out.
If you followed all the planting rules, you may have planted infected tubers. The fungus could get on the potatoes even when diseased and healthy root crops were lying next to each other.
Late blight is so insidious that treatment does not always give the desired result. So the drugs need to be changed.