Prevention and treatment of potato scab

If vegetable crops grow on the site, then most likely there are potatoes on it. Large areas are allocated for this root crop, so the necessary crop rotation is not always possible to arrange. As a result of planting potatoes in one place, she may develop some kind of disease; the most common of all the possible list is potato scab. When it occurs, the tubers of the vegetable are affected.

Diseased tubers do not threaten human health, they are quite suitable for use, but their nutritional value is lower than healthy ones. In this case, the starch content in the harvested crop is reduced by almost half. But these are not all the "gifts" of the scab. Such potatoes are poorly stored, rot develops in it faster. A rich harvest can turn into a rich amount of waste: potatoes, which took so much cultivation effort, are simply thrown away. Successfully overwintered diseased tubers, planted again on the site, will not bring a healthy generation. The general lesion of the peel also extends to the eyes, they will hatch, but they will give weak shoots, so you can forget about a good harvest.

Such a disease can be ignored for a while, but it tends to spread quickly, covering more and more new tubers, and the spores of the disease are very viable, they can successfully be in the ground for up to 3 years.

Scab forms and signs of damage

Potato scab, like any serious disease, has several varieties. We will provide a description of each here so that you can accurately identify the affected tubers.

There are 3 forms of scab:

1. common scab;
2. powdery scab;
3. the scab is silvery.

Common scab develops comfortably at high temperatures (+ 25-30 degrees) and in alkaline soil, depleted in moisture. If you carried out liming of the soil on the site, then this is also a favorable factor for the development of potato scab. The causative agent of the disease is formed on organic residues in the soil and, if favorable conditions are created, passes to the tubers through any mechanical damage to the peel. When storing potatoes, you cannot get infected with the disease, so it does not develop, this is possible only in the soil, but when infected, it is preserved until next year and does not disappear anywhere. Only tubers are affected, you can notice this if you dig up the root crop. Visually, these are ulcers that have an irregular shape; with the growth of potatoes, these areas also grow in size and harden. Sometimes the affected areas form cracks. You can even observe a picture when the potato is completely covered with such formations. Scab opens the way in tubers for both dry and wet rot pathogens. The causative agents of the disease are very viable; they can successfully exist in the soil for years. The most susceptible to this type of scab are varieties with a thin skin or having a red color.

Another type of potato scab is a powdery scab, generated by a special type of fungus that can move independently and is a small slimy lump. In this case, not only the tuber is affected, the roots and the underground part of the stem get sick. During storage, the infected tubers dry out, and if there is a slight excess of moisture in the storage, the potatoes actively rot. The visually diseased tuber is covered with a colony of "warts". The spots can have different shapes and pronounced relief.When the potatoes have already been dug up, these formations dry out so much that the peel bursts, forming ulcers. These ulcers are filled with a dusty brown substance, which includes fungal spores and the remains of potato tissue. These potato "craters" are star-shaped with the edges turned outward. On the roots, the disease manifests itself as the formation of irregular white growths. The source of such a misfortune is the soil infected with the disease, manure and damaged planting material. Favorable conditions for powdery scab are waterlogged soil, while the temperature can be relatively low - 12-18 degrees. Most often it develops on heavy soils, where it retains its viability for 5 years.

The silvery scab of potatoes differs from previous diseases in the main feature - the affected tuber does not rot during storage. Here the action is somewhat different. Affected tubers lose moisture and, accordingly, weight. The peel is wrinkled, has a silvery sheen in the affected areas; lesions are especially noticeable on red-skinned varieties. The causative agent of this type of scab is a type of fungus; it penetrates the tuber through the soil and spreads to other tubers. During harvesting or storage, gray-brown spots of various sizes form in the potatoes, they can be slightly depressed, if you peel the peel, then black formations are observed under it. Lesions are clearly visible in early spring or on green potatoes. Diseased tubers do not germinate well. This disease is formed when vegetables are grown on sandy loam, as well as on loamy soils, if there is an elevated temperature during the period of tuberization. The disease spreads at high humidity - more than 90%, and temperatures higher than 3 degrees.

Prevention and treatment methods

Each of the forms of scab considered by us has different pathogens, but the result is the same - the potatoes deteriorate, and the yield of the site decreases. Even if you did not find signs of the disease on the dug tubers, this does not mean that it will not come to your garden next year, so you should know not only the methods of treatment, but also take preventive measures. And you can deal with potato scab in any of its manifestations.

You should monitor the planting material - this is the most important rule. Try to take only healthy, viable tubers for planting. Use the measures of pre-planting dressing of tubers, there are special preparations for this. If, nevertheless, slightly affected tubers were caught in the planting, then during the flowering period of the plants, the potatoes should be watered abundantly with water. Copper, manganese and boron when applied at planting significantly reduce the incidence of disease.

Try to change the place of planting potatoes and alternate it with planting legumes. If the place is permanent and it is not possible to change it, never apply fresh manure as fertilizer.

If your soil has alkaline characteristics, it should be acidified, for this we use a solution of ammonium sulfate - 2 tbsp. tablespoons of the substance per 10 liters of water. Water during flowering at the rate of approximately half a liter per 1 bush.

10-14 days before harvesting the potatoes, it is useful to mow all the tops so that the potato peel gets stronger.

After harvesting, plant green manure in an empty area. They will bring a large warehouse to the improvement of the soil and saturate it with useful substances. These can be cereals (rye, wheat), legumes (lupine, peas), cruciferous (rapeseed, mustard) or mixtures of these crops.

Monitor the environment in the room where the potatoes are stored. Avoid excessive moisture and heat.

Zircon can suppress the development of potato scab. It is used during the budding period. This is a growth regulator. Even its single use gives a high positive effect, and the yield increases at the same time.

The preparation "Fito Plus" is able to significantly reduce the infestation of tubers.They should process the planting potatoes and spray the plant during the growing season. Dose for use - 1 sachet for 3 liters of water.

Highly resistant varieties

The varieties bred in our country: Aspia, Bezhitsky, Bryanskaya novinka, Ramensky, Varmas, Vestnik, Vilnya, Vyatka, Zhukovsky early, Lyubimets, Posvit, Prasna, Reserve, Spring, Skoroplodny and others.

There are also foreign analogues: Alpha, Element, Krostotr, Lady Rosetta, Mentor, Nicolas, Ostara, Patrones, Prevalent, Prokura, Saturn.

Do not forget about preventive measures even when using varieties that are highly resistant to potato scab, and then your harvest will only delight.

Video "Potato scab and how to deal with it"

The video tells about such a disease of potatoes as scab, and about methods of dealing with it.