The potatoes, which have fallen in chips, lose about 30% of starch, their taste is made worse, and they are stored much less time. Since the diseased potato is in the ground, then immediately notice and cure the disease, when the potatoes grow, it is impossible. Because of this, it is very important to carry out preventive measures for the disease..
Table of contents
- What is a scab in potatoes?
- As manifested in potatoes
- Risectoniasis (black scab)
- Where does the disease come from and how does it develop?
- How to fight
- What types of potatoes are considered highly resistant to disease
What is a scab in potatoes?
Parsh - a disease caused by a fungus, usually more oftenaffects tubers, sometimes roots and part of the stem, located under the ground..
As manifested in potatoes
Parsha on potato is divided into 4 forms: ordinary, silvery, powdery and rhizoctonia (black scab).
Spores of the fungus penetrate the tubers through the cracks in the peel. When stored, the potatoes do not become infected, since under adverse conditions the pathogens are at rest, but do not die.
Scab usually falls on potatoes, which has scarlet or thin peel. If you plant potatoes deep into the ground, intensively watered with the growth of tubers, then the risk of falling ill.
Symptoms: visible on tuberssolid ulcers of irregular shape, ulcers can cover all the potatoes or on the diseased places on the peel cracks are visible.
It often appears if the potatoes are planted in sandy loam and loam, the optimum air temperature for the disease is 18-20 degrees, and humidity is increased by 85-100%.
The fungus penetrates the tubers through the ground, then passes over to the remaining potatoes. The difference between this form and others -diseased tubers do not rot in the vaults, but only lose moisture.
Symptoms:the skin is wrinkled, a silvery color appears on the diseased areas, it is especially evident in varieties with scarlet skin. Gradually the brownish-gray spots grow, sometimes they look depressed.
She ismost common, it is a pathogen that can move. The disease occurs on tubers, roots and the underground part of the stem.
When placed in storage, sick potatoes dry, but if the environment is excess moisture, the potatoes rot. Often in diseased potatoes, even late blight and dry rot are added to the scab.
Sources - land, diseased seed potatoes and manure (when feeding cattle with diseased potatoes, fungal spores do not lose activity even after passing through the digestion of a cow). The disease occurs on heavy lands that have excess water at a temperature of 12-18 degrees.
Symptoms:on the roots visible whitish growths, having a diverse form, gradually they become brown. On the diseased tuber, warts and various spots are visible. After a while, the diseased areas dry up, after bursting and appearing ulcers, they show a gray-brown substance - spores. More potatoes rot.
Risectoniasis (black scab)
Can hit potatoes with a strong humidity and air temperature of 17 degrees, if the spring is often precipitation, and cold weather. Loss of harvest from black scab -20-25%.
Symptoms:black spots on tubers, reminiscent of the earth, they can not be washed off from the tubers and difficult to scrape, but they do not harm the tuber. The diseased bushes wither in the daytime, grow low, they have twisted leaves. If there are rains and heat, then on the stem you can see the "white foot".. .
Where does the disease come from and how does it develop?
Reasons for the appearance:
- The affected land.
- Sick tubers, on which the disease is not visible, but there is a fungus, since it is not visible at the initial distribution.
- The overabundance in the nitrogen soil stimulates the development of the scab.
- If you plant potatoes in one place from year to year, then in the ground there will be diseases.
- High ground temperature.
- Earth, which has acidic properties.
- Soil fertilization before planting potatoesfresh manure.
How to fight
MaksimIs a contact fungicide. Killing the fungus, Maxim retains the useful microflora of the earth. Add 4 ml of Max., 5 - l of water. Use, processing 10 kg of tubers.
To get rid of the disease tubers are sprayed before planting:
- 13 g Agata25K added to 1 liter of water, this composition is enough for 100 kg of potatoes;
- 10 g Phytosporin M is dissolved in 5 liters of water, use this rate for 20 kg of tubers;
- 10 drops Krezatsina drip into 2 liters of water, use this composition for 40 kg of potatoes.
Phytosporin is sprayed with bushes3 times per season, in 1 packet of the drug add 3 liters of water, after spray.
Take 25-50 g of Kuprosata, add to the ten-liter bucket of water, spray the bushes. The second time the bushes are treated after 10 days, but no later than 20 days before digging out the bushes.
The bushes are also sprayed with preparationsAlbit, Colfugo, Acrobat MC, Mancozeb, Profit Gold, Fenoram super, Ordan.
- For landing, selectabsolutely healthy tubers. Before planting tubers should be treated with special compounds.
- Every year, change the place of planting potatoes, plant potatoes after beans, peas, beans. Do not use fresh manure as a fertilizer.
- If you have alkaline soil, then make it more acidic by adding a solution of 2 tbsp. spoons of ammonium sulphate in a ten-liter bucket of water and strait plot. When flowering under one bush pour, l solution.
- 14 days before the digging of potatoesshave the tops.
- The room for storing potatoes should be dry and cool.
What types of potatoes are considered highly resistant to disease
- Alyona- early variety. The tubers are oval, they have a scarlet skin and a white flesh. Potatoes are resistant to scab, cancer, drought. But it is not resistant to late blight, it will have to be fought with.
- Snow White- medium-early variety. It is good and long to be stored. It has resistance to scab and late blight. Oval tubers have a yellowish skin and white flesh, eyes are tiny.
- Resource- mid-ripening. Resistant to drought and heat. Almost not prone to viral diseases, scab. Resistant to mechanical damage. Tubers oval with a beige skin.
- Lasunok (Lasunak)- mid-late, it is withdrawn in Belarus. It has excellent taste, high yield. Resistant to scab, it is almost not affected by the Colorado beetle.
- Pace- late. A large, round-flat with a creamy hue and a creamy hue of flesh, has a wonderful taste. Resistant to scab.
In order that the potato is not affected by scab, it is worthwhile to select for planting special varieties that are resistant to this disease, and also not to neglect the prevention..