What are the diseases of potato tops: description and treatment
Diseases of potato tops lead to yield loss and a decrease in the starchiness of tubers. The main cause of disease development is pathogenic microorganisms. Preventive measures, the use of healthy planting material, treatment with chemicals and proven folk methods will help preserve the harvest.
Read more about why potato tops turn yellow and dry out ahead of time and what to do if the potatoes have wilted.
Reasons why potatoes can get sick
Pathogens – fungi, viruses and bacteria. Non-communicable diseases arise under the influence of environmental conditions. During drought and high soil temperatures, early frosts, and lack of nutrients in plants, physiological processes are disrupted, which leads to a decrease in productivity and a deterioration in the seed qualities of tubers.
How to distinguish diseases from a lack of microelements and errors in cultivation and care
With a lack of nutrients and errors in care, physiological diseases develop.
Difference between physiological diseases and infectious diseases:
- there is no pathogen;
- at the same time, most of the plants in the garden are massively affected;
- the course of the disease can be suspended or stopped completely by eliminating the harmful environmental factor.
A lack of nutrients simultaneously manifests itself in all organs of the plant and rarely leads to its death.. Most often, potatoes are stunted. The leaves change color, become deformed, and the ovaries die. Excess micro- and macroelements causes leaf burn and death of ovaries.
The table clearly shows the signs of mineral nutrition disorders:
|
Element |
Symptoms |
|
| Flaw |
Excess |
|
| Nitrogen | Light yellow leaf color, stunted growth | Delayed flowering, leaf burns, plant death |
| Calcium | The apical leaves turn pink and curl into a funnel | Symptoms of poisoning are unknown |
| Phosphorus | The leaves become smaller, brighten, and are located at an angle to the stem. During tuberization, a narrow brown stripe appears at their tips. | Rarely manifests itself as chlorosis |
| Bor | Dying of the growing point, increased development of lateral shoots. Internodes are shortened, the bush seems squat | During drought, seedlings are delayed, growth is weakened, and chlorosis develops. With sufficient rainfall or timely watering, potatoes recover |
| Potassium | The leaves first turn dark green, then turn bronze, wrinkle and curl downward. | Potato leaves turn black and become smaller |
| Copper | Dying of leaves in the upper tier | Dark green leaves |
| Manganese | Chlorosis of leaves between the veins. With severe starvation, necrotic spots form | Chlorosis on the edges of old leaves |
| Zinc | Necrotic spots on the underside of the leaf blade, chlorosis of the bases of the leaf lobes, spreading to their apex | Leaves turn red and die |
Freezing, high humidity or drought lead to wilting and lodging of the tops, necrosis and spots on the leaves.
It can be useful:
What are the diseases of potato tops?
Infectious diseases – fungal, bacterial and viral, transmitted from diseased plants to healthy ones.
Fungal
Fungal spores penetrate plant tissue through stomata or mechanical damage. The mycelium grows, penetrates the cells, feeding on cell sap. Plant metabolism is disrupted, growth slows down, and the yield and keeping quality of tubers decreases.
Late blight
Appears at the beginning of flowering. Rapidly growing brown spots form on the lower leaves. With high humidity, a white coating forms at the border of healthy and affected areas. In hot weather, the leaves dry out and die, in rainy weather they rot. The stems are covered with oblong brown spots. Pathogen late blight persists in soil and on seeds.
Alternaria blight
Potato Alternaria develops in the budding phase. Brown or black spots with concentric zoning appear on the lower leaves. Then they merge - the potato tops turn black, the leaves dry out and die. The development of the disease is favored by hot weather with heavy rains and morning dew, and a lack of nitrogen.
Fusarium wilt
Distributed in the southern and southeastern regions. Pathogen most often affects potatoes during the flowering period. The upper leaves lighten and fade. The lower part of the stem turns brown, becomes covered with a pink coating and dies. Potato tops turn yellow and dry out within a few days.
Verticillium wilt
Affects potatoes during the flowering phase. First, the edges of the leaves turn yellow, then light brown spots with a yellow border appear on the plate. In rainy weather, the stems and lower leaves become covered with a thin gray coating.
Black scab, or rhizoctoniasis
Affects stems, causes rot and death of seedlings in areas with cold, long springs. Seedlings grown from sick rhizoctoniasis tubers become covered with brown spots and die. The bases of the surviving stems rot during the flowering phase and become covered with a white felt coating - a “white leg” is formed.
Fomoz
Affects tops in the second half of the growing season. Elongated spots appear on the stems, which lighten over time.
Treatment methods
Use chemical fungicides – “Thanos”, “Mancozeb”, “Novozir”, “Profit”. During the growing season, the tops are sprayed with a 0.2–0.3% solution.
tops treated with biological protective drugs 2-3 times with an interval of 7-10 days, starting from the budding phase:
- “Ecosil” – dilute 5 ml in 1 liter of water;
- “Bitoxibacillin” - use 30 g per 1 hundred square meters;
- “Baktofit” – 30-50 ml per hundred square meters;
- "Gibbersib" - 0.015 g per hundred square meters;
- "Fitosporin" - 6 g per hundred square meters.
Traditional methods:
- before planting, the tubers are treated with copper sulfate - 2 g per 10 liters of water or potassium permanganate - 10 g per 10 liters of water;
- take 100 g of copper sulfate and soda ash, dilute them in 10 liters of water and spray the tops during the growing season - 4-6 liters of working solution will be required for 1 hundred square meters.
An effective method of combating fungal diseases – drying the tubers in the sun for 4 hours immediately after digging.
Bacterial
Sources of bacterial infection – soil, weeds from the Solanaceae family, infected tubers.
Ring rot
Stems affected by ring rot wilt from the top. In humid weather with moderate temperatures, wilting occurs slowly, and intensifies in hot weather.
Brown rot
Brown bacterial rot causes the formation of brown oblong stripes on the basal part of the stem and on the veins. The first signs appear during the flowering phase - the stems dry out, the leaves wither, wrinkle and droop.
Blackleg
Black potato leg begins with yellowing of the lower leaves. The upper leaves grow at an acute angle and turn yellow later. The stem rots, softens and easily breaks off in the area of the root neck.
Treatment methods
Diseased plants are removed throughout the growing season.. The risk of disease development is reduced by timely mowing of tops and removing them from the field.
Folk remedies
1 kg of dried wormwood is boiled for 10-15 minutes in a small amount of water. Cool, add 1 liter of infusion of dry bird droppings (1 kg of droppings are infused for 1-2 days in a small amount of water). The mixture is filtered and added with water to 10 liters. Add 40 g of laundry soap shavings to the working solution. Potatoes are processed from the beginning of budding 2-3 times with an interval of 2 weeks.
Tops also sprayed with tobacco decoction.
Chemical
On the day of planting, the tubers are treated drug "TMTD" (2.1-2.5 l/t).
Before storing potatoes, they are treated with a fungicide. “Maxim” - take 2 ml of the product for 10 kg of potatoes, dilute it in 50 ml of water and spray it.
Biological method: pre-planting treatment with Planriz fungicide - 100 kg will require 1 liter of 0.1% working solution.
Viral
Diseased plants cannot be treated. Pathogens accumulate in subsequent generations of tubers.
Important! Viruses are transmitted from diseased plants to healthy ones by contact - insects, fungi, nematodes, cutting tubers, contact of stems, leaves and roots.
Speckled mosaic
Speckled or ordinary mosaic leads to a sharp decrease in photosynthesis. Light green spots of various shapes and sizes form on young leaves. The tops are stunted, the leaves turn yellow and fall off prematurely.
Striped mosaic
Appears as necrotic stripes, mosaics or spots on the leaves. On the underside of the plate, dark brown streaks and spots form on the veins. From the lower tier, the damage spreads to the petioles and stems. By the end of the growing season, the leaves dry out and fall off.
Wrinkled mosaic
Causes up to 30% yield loss. The color of the leaves becomes lighter, the edges of the blades bend down, and corrugation forms. The leaves die and hang on the stems without falling. The disease appears en masse in hot weather in the middle of the growing season. Plants do not bloom, ending their development 3-4 weeks earlier.
Curling leaves
Leads to net necrosis of tubers, reduces yield by 50%. The lower leaf blades curl along the midrib, then become hard and rustling. The development of the disease is promoted by hot weather and lack of moisture.
Vein banding
Causes deformation of the bush and stunting. Light brown stripes and streaks appear on the leaves. The veins become watery and the leaves die.
Disease Control
Control methods include treatment with biological products for preventive purposes. “Agat 25 K”, “Biosil”, “Fitosporin-M”, “Gumi-20M”. Before planting, the tubers are soaked for 1 hour in the working solution, then dried.Biological products containing a live culture of bacteria and mineral elements develop resistance to viral diseases in potatoes.
Prevention measures
To prevent the development and spread of diseases, observe crop rotation – potatoes are returned to their original place no sooner than after 3 years. The best predecessors are legumes, grains and melons.
Before storage or before planting, the tubers are heated for 2-3 weeks at a temperature of +14...+18°C. During this time, diseased tubers are identified and only healthy material is used.
When choosing a variety, take into account that early-ripening potatoes are most susceptible to diseases. Varieties resistant to viruses are grown - Zekura, Lady Rosetta, Moskvoretsky, Pamir, Luck, Lugovskoy, Maidas.
Insecticides are used to kill insects, disease carriers - aphids and leafhoppers. After harvesting, all tops and weeds that harbor infections are burned.
Potato bushes grown from overwintered tubers are destroyed.
Tips and tricks from experienced gardeners
Gardeners share their experience in treating potato tops diseases.
Irina, Yaroslavl: “I inspect the potato plant every day. I destroy bushes with ring rot, pour 1 liter of copper sulfate solution into the hole - 100 g per 10 liters of water.".
Maxim, Bryansk: “Before planting, we treat the soil against fungal diseases with a solution containing copper. In the spring, before digging, dilute 1 tbsp in 10 liters of water. l. copper sulfate or copper oxychloride at the rate of 0.5 liters per 1 m². The second time we spray with Bordeaux mixture 1% at the rate of 0.5 liters per 1 m².”.
Anton, Pskov region: “The resistance of tubers to frost and disease increases if the potatoes are fed with potassium sulfate or wood ash during flowering. I dilute 2 tbsp in 10 liters of water. l. potassium sulfate or 2 cups of wood ash, pour 0.5 liters under each bush. Potassium sulfate can be replaced with potassium chloride".
Conclusion
A set of techniques, including preventive and protective measures, will reduce crop losses from diseases of tops and tubers. Studying the causes and symptoms of diseases, timely chemical and biological protection, the use of disinfected tubers when planting - these measures taken in combination will reduce the likelihood of plant damage.