How to deal with scab on potatoes and heal the land
Scab is one of the most common fungal infections in potatoes. The disease spoils not only the appearance of the tubers. Deterioration in taste and reduced storage. The spores of the fungus multiply quickly and capture more and more plants, so it is worthwhile to understand the reasons for its appearance, and learn how to get rid of the scab on the potatoes. Photos and descriptions of scab species will help to more accurately diagnose the disease and take effective measures in time.
The content of the article
What is potato scab
Outwardly, it resembles scabs on tubers. The defeat begins with small ulcers - if you do not pay attention to them in time, the disease reaches an extreme degree of manifestation - the appearance of deep cracks with torn edges. Bacteria develop in these tubers and the potato rots.
Disease spread
The disease affects mainly tubers., extremely rarely goes to tops and roots.
Fungus spreads by spores from one bush to another and gradually captures the entire field, if measures are not taken in time. Spores survive in the ground for up to three years, which is why it is so important to change the planting site.
You can spread the fungus by using fresh organic matter.: scab spores remain functional after passing through the digestive tract of the animal. The cause of the disease may be incomplete disposal of infected potato tops in autumn.
It is impossible to notice the scab during the growth of potatoes., therefore, it is important to take into account the presence of fungus on the tubers during harvest and take preventive measures for the next year.
Causes of potato infection
The main reasons for the defeat of culture:
- non-observance of crop rotation - it is important to change the planting site at least once every three years;
- planting diseased tubers;
- increased nitrogen content in the soil;
- hot (25-30 ° C) dry weather promotes the growth of the fungus;
- improper application of organic fertilizers;
- weak soil acidity;
- improper potato storage equipment - high temperatures and humidity, a large volume of potatoes with poor ventilation.
Reference. Loamy and sandy loam soils are more susceptible to scab damage. Before planting, the tubers must be pickled. Potatoes are planted deeper to exclude an excess of oxygen.
How does scab appear on potatoes
There are several types of scab, depending on colors, shapes and signs of damage.
Ordinary
Tuber spots in the form of hard sores with a dry rim of dark yellow or brown... They can cover whole potatoes or separate areas. Common scab appears due to shallow planting and air access to the tubers, with improper introduction of lime and wood ash into the soil. It manifests itself in poor moisture soils.
Spores enter the tuber through mechanical damage to the peel... Often exposed to fungus varieties with a thin red skin. The affected vegetable is poor in minerals, vitamins and amino acids.
Silvery
A distinctive feature is the appearance in the form of silvery spots... First, brown spots or black soot-like spots form. When the skin peels off, a gray spot appears in its place. The tuber becomes wrinkled. The spot size can cover up to 40% of the total tuber.
This type of fungus dries tops, which leads to early death of the entire plant., softens the affected tuber, drying it out. The taste of such potatoes is unpleasant, they are not suitable for planting. The development of the fungus begins at a temperature of + 3 ° C and high humidity (80-90%).
Other potato diseases:
Powdery
Sign - small focal growths on the stem... White growths are visible on the tubers, which turn brown over time. The ulcers contain brown dust from the spores of the fungus and the remains of the tuber tissue. Subsequently, the potato rots.
Sources of the disease - infected planting material, manure, humus, chicken droppings... Another reason is too wet soil. This type of scab affects the roots and stems of vegetable crops. Tubers become susceptible to late blight and dry rot.
Black, or rhizoctonia
Develops in high humidity and affects the plant from tuber to leaves... This type of fungus looks like black loose spots, similar to adhering lumps of earth. Cover the tuber in small areas not more than 5 mm in girth. If the disease is activated in the early stages of plant development, it can destroy the entire bush.
The tubers are poorly stored, the rot does not develop deeply, but other types of rot are often formed on itthat destroys the crop completely. Early detection of potato rhizoctoniae will help start treatment on time.
Lumpy
Only tubers are affected - tubercles appear, which then turn into pits with putrid contents... It manifests itself brightest in the third or fourth month of storage. Poorly dried tubers suffer the most.
How to deal with scab
There are many methods of dealing with scab - folk recipes, chemicals and biological methods.
Folk methods
Use available organic fertilizers and herbal remediesthat increase the resistance of tubers to scab. At different stages of growth, the following medicinal compositions are used (the ratio of the mass of fertilizer and water is indicated):
before germination, the planting material is sprayed with a 1.5% solution of boric acid;- when planting, 1 l of poultry manure solution (1:15) is introduced into each well;
- during the period of stem growth - watering 0.5 liters of liquid mullein or bird droppings per 1 bush (0.5: 10 liters);
- during the formation of the bush - watering 1 liter per bush of weekly infusion of nettle (10 kg: 100 liters);
- during the budding period, 1 liter of ash solution is poured under the bush (3 tbsp. l.: 10 l);
- during flowering, 0.5 l of mullein solution is added to the bush (2 glasses: 10 l).
Chemical and biological methods
In addition to folk methods, the following drugs are effective:
- "Maxim". Tubers are sprayed with the drug in the fall before storage (2:50 ml of water) and in the spring before planting.
- "Prestige KS". Tubers are treated before germination (70-100 ml of the drug is dissolved in 1 liter of water).
- Fitosporin M. To treat tubers, before planting, dilute 10 g of the drug in 5 liters of water. During the season, 3 treatments are carried out with watering the bushes.
- "Agat-25". Seed potatoes are sprayed before planting, the bushes are treated (7g per 500 ml of water).
- "Quadris". Serves for soil cultivation and protects it for two months (3 ml per 10 l of water). The composition is enough for spraying 10 m² of land.
How to cure the earth from scab
How to heal the soil if scab has appeared on the potatoes? A simple way is to use green manure plants that disinfect the soil.
Example. You can sow mustard. When the shoots are 15-20 cm tall, dig up the ground together with young greenery. Also sprinkle dry mustard between the bushes before watering.
Agrotechnical method: the site is sown with cereals (oats, rye), legumes (clover, vetch, soybeans), cruciferous (mustard, rapeseed, oil radish) or these crops are sown in the fall. The next year, potatoes are planted in this place.
Alkaline soils require acidification with ammonium sulfate at the rate of 2 tbsp. l. 10 liters of water. A barrier for the fungus will be created by superphosphate, potassium magnesium, potassium permanganate, boric acid and copper sulfate.
Is it possible to eat potatoes with scab
Scab is not dangerous for human health, but the taste of the infected tuber is noticeably deteriorating... The starch content in it drops by 2 times, and with it the content of nutrients. Tubers affected by scab are poorly stored and rot.
They also cannot be used for planting, since this will entail further spread of the disease, the appearance of even more ulcerated tubers, and a decrease in the yield in general.
Read also:
Scab-resistant potato varieties
There are no varieties of potato crops that are absolutely resistant to this disease, but gardeners noted early ripening varieties that are less susceptible to damage: Spring white, Lugovskoy, Zhukovsky early, high-yielding variety Elizaveta with tasty tubers, which is suitable for growing in the middle lane, in the Far East and North Caucasus. Temp is a late ripening variety characterized by scab resistance, high yield and good keeping quality.
Also have variety immunity Amber, Domodedovsky, Zarechny, Alena, Snow White, Resource, Lasunok.
Infection prevention measures
Rehabilitation of potatoes is carried out in the directions protection of tubers and destruction of fungus in the soil in the following ways:
- compliance with crop rotation;
- refusal to fertilize the soil with fresh manure;
- drying the crop;
- careful selection of seed potatoes without signs of scab damage;
- seed dressing with special preparations (polycarbocin or "TMTD");
- storing potatoes in a cold, dry, ventilated area;
- sprouting potatoes in the light - greening (protects not only from scab, but also from many diseases, as well as from rodents and insect pests);
- regular watering of the bushes during bud formation and flowering;
- choice for planting scab resistant varieties.
Before being sent for long-term storage, the potatoes are dried for several hours and the infected one is immediately destroyed.... Scab spores can spread through the air. This is facilitated by the humidity of the room, therefore it is important to avoid the formation of condensation in the vegetable store.
Conclusion
Scab is a common disease that affects not only potatoes, but also other crops. Having discovered signs of the disease, they immediately begin to fight for a healthy harvest. By cultivating the soil and planting tubers, using a useful vegetable neighborhood in the potato plot, knowing what actions lead to the spread of the fungus, observing the crop rotation, you will definitely achieve positive results and get rid of this disease.