A lot of trouble brings potato disease to potato growers. Photo, description and treatment of scab (rhizoctonia), dry rot - the subject of our conversation. After all, potatoes are the main food in many countries. It is easy to grow on a private plot, which makes it popular with gardeners, truck farmers. But potatoes are susceptible to many diseases. The main pathogens are various fungi, bacteria, viruses. Prevention is almost the only remedy. Many diseases can be prevented if preventive measures have been taken in time or the treatment is started at the initial stage.
.- Scab or rizoctonia is a common disease of potatoes
- Description of the disease
- How to struggle, how to protect the harvest
- Dry rot
- Description of the disease
- Control and prevention measures
- Can I eat contaminated potatoes?
Scab or rizoctonia is a common disease of potatoes
Description of the disease
Scab, black leg or rhizoctonia is a fungal disease of the potato that occurs wherever it is grown.
The causative agent is the fungus Rhizoctonia Solani, which can be found in the soil, even when there is no potato. The parasitic activity of the pathogen is determined by the temperature, humidity, and state of the host plant. The pathogen of rhizoctonia infects not only tubers, but also other parts - stems, stolons, roots.Rizoctonia is one of the most common fungal diseases of potatoes on household plots, called a black leg or black scab. Especially the big damage he causes under conditions favorable for the development of pathogens.
Rizoctonia - manifests itself in the form of black scab, rotting of eyes, sprouts, death of roots, as well as "black stem" stems in wet weather. At the beginning of the disease, the lesions on the stalks, roots, stems are reddish-brown in color. When they mature, they turn into coarse ulcers with cracks. If the ulcers are significant, they can gird the stem, preventing the normal movement of juices and carbohydrates throughout the plant. Thus, the symptoms of the disease can be seen on the ground and on the tuber.
.On infected stalks, stems above or below the soil surface level, you can see sunken brown ulcers of various sizes and shapes. These ulcers can be shingles - in this case, the plant sooner or later dies. On such stolons can not originate, develop young nodules.
Black plaque is the most visible sign of a potato disease. In this phase of the disease, the fungus Rhizoctonia Solani forms outgrowths from dark brown to black, as if potatoes are stained in the ground. But this is not the earth, these are the so-called sclerotia, which are on the surface. They are irregular in shape, ranging from small flat spots to large convex spots. Although these structures closely adhere to the surface of the tuber, they do not penetrate inside, do not spoil the taste of potatoes.
However, if such potatoes are used as seed material, the sclerotia will hamper the development of planted potatoes - they can even destroy it. This is because during the growing season the fungus Rhizoctonia Solani affects the root system, the base of the plant stems. The movement of nutrients from leaves to young tubers is disturbed. The upper leaves twist along the main vein. It creates the appearance that they are affected by aphids.
The main source of infection is the seed material. Sometimes heavily infected potatoes can not even form stems. This symptom is called "without top it can be confused with the same symptoms as growing from physiologically old seeds.
↑ back to content ↑How to struggle, how to protect the harvest
Treatment of rhizoctonia, black scab, requires an integrated approach, knowledge of each stage of the disease. One of the most important means of combating the disease is the acquisition, planting of seed material only of high quality, which is not infected with pathogenic fungi.
Effective way to fight potato diseases - prevention - presowing light germination of tubers. The introduction of overgrown manure, superphosphate, potassium fertilizers reduces the negative effect of the pathogen.
Potatoes are best planted after corn, beets, beans, peas.The weakest plants are the most affected, but it practically does not affect the germs of germinating tubers. Therefore, it is very important to plant potatoes before planting, that it would be possible to discard potatoes infected with rhizoctonia prior to planting. It is equally important after the rain to loosen the soil so that a crust does not form. In this case, favorable conditions are not created for the fungus that causes the disease.
.Processing of potatoes before planting,% solution of boric acid also protects it from infection with rhizoctonia. The volume of the solution should be prepared at a rate of 50 ml per 1 kg of tubers.
.The disease is most strongly manifested in cold and wet seasons. Microspores persist in potatoes or in plant residues up to two years. When cutting seed with the presence of infected tubers among them, for example, when growing potatoes from the eyes, it is possible to infect healthy ones. So do not forget to remove from your site sick bushes. Cut the tops before digging the crop so that the bacteria of the rhizoctonia can not get from the leaves to the tubers. Be sure to sprout the seed material in time to remove the sick potatoes. Try to be sure to warm in the sun, dry, and green the seed before removing it for storage.
↑ back to content ↑Dry rot
Description of the disease
Dry rot is caused by several species of fungi of the genus Fusarium, hence the name dry fusarium rot. If you, when examining potatoes periodically in the cellar, find dry, dented spots on the peel, this indicates that it is affected by dry fusarium rot. These spots are the first symptoms of the disease. As a rule, they appear on the surface of the tuber. Gradually the flesh under the stain dries up, becomes rotten. The skin is wrinkled, torn. In the resulting voids, the mycelium grows, that is, the mycelium with maturing spores.
Causes dry rot of potatoes fungi of the genus Fusarium of several species. Depending on the type of spores are similar to grayish-white, yellowish or pink convex pads.
Where could this potato disease come from? This can be said at the location of the spots.
If the dry rot on the tubers only appeared from the side of the stylon end (a small dent on the potato, where the stolon was attached), then all the soil of your garden is infected with this fungus. Let us explain: the stolon is a lateral underground shoot, at the end of which the potato tuber ripens. This potato "umbilical cord according to which a growing tuber gets nutrients from the bush.
And if the potatoes are hit from different sides, then the reason for improper harvesting, poor storage. Most often the disease begins to rage where there have been injuries, cuts, lesions of phytophthora or scab.
Perhaps it's too warm in your cellar. At an increased storage temperature, dry rot rapidly develops and spreads. As is known, the optimal temperature for storing potatoes is 1-3 degrees above zero.
.Control and prevention measures
Most methods to combat this disease of potatoes are aimed at preventing tuber injuries during harvesting or laying for storage. Preventing damage to the surface of the potato will greatly help avoid infection.
If soil is contaminated in your area, then it should not be planted there for at least five or six years. Ciderates or crops sown in such a field will remove the fungus from the ground, but this may take several years. Therefore, the main thing is to prevent contamination of the soil. And this can be achieved only by careful selection of seed material.
↑ back to content ↑Can I eat contaminated potatoes?
Is it possible to eat potato infected with scab? Or should they be thrown away? Not at all. Select them, remove the damaged parts. Feel free to fry potatoes for dinner or cook mashed potatoes.
On the contrary, potatoes affected by dry rot, is not recommended. Even if you have a tuber struck only on one side, you should not eat, supposedly healthy, the other half. Be completely sorry, throw out the whole tuber.
.To ensure that your potatoes are healthy, select or buy for planting quality seed. Pay attention to the characteristics of the variety, the resistance to a disease. Potatoes intended for future planting, dig out earlier than for food and storage, as the longer it will be in the ground, the greater the likelihood of infection. Try to observe a crop rotation.
