Potato cancer is one of the most dangerous diseases affecting potato tubers. As a result of infection, the fetus has an unattractive appearance. The worst thing is that it becomes unfit for consumption. Cancer is common not only in European countries, but also on other continents.
Signs of potato damage
The disease is distinguished by certain symptoms. If you identify them in time, you can prevent the spread of infection and preserve a healthy part of the crop. Potato tubers are covered with growths that are similar to the shape of cauliflower. As a rule, they appear from ocelli.The size can vary from a few millimeters to tens of centimeters.
The growths on the potato tuber at the beginning of the disease have a light yellow tint. Over time, the color changes to dark brown. The infected fruit disintegrates and rots. In rare cases, they appear between the lower leaves and stems. If the roots remain untouched, this means that the disease affects young tissue.
Signs of the disease may vary depending on climatic conditions. If they are unfavorable, the leaf-like growths are shaped like a pine cone. The top is covered with small hard crusts, similar to scab. The corrugated form of infection leads to the fact that the tubers become wrinkled, the potato skin becomes covered with depressions, ridges and waves.
The causative agent of the disease
The development of the disease occurs under the influence of a pathogenic fungus. Its name is Synchytrium endobioticum (Schilb.) Perc. In addition to the potato tuber, it also parasitizes tomatoes, wild nightshade and physalis. In this case, the fungus attacks the root system of crops.
Features of the pest
The fungus cannot survive drought or cold. Therefore, there is no potato cancer in the southern and northern regions. In the first case, over a long period of time, the soil warms up to +30 °C to a depth of 10 cm. In the second, it freezes to -11 °C.
Overwintering of the pathogenic fungus in the soil occurs in the form of zoosporangia. They are cysts covered with a durable membrane. In spring they transform into zoospores. Zoosporangia tend to live in the soil for 30 years, waiting for suitable conditions.
For the fungus to fully develop, the soil temperature should be in the range from +15 to +18 °C. At the same time, the humidity is not less than 80%. The same conditions must exist for normal potato growth.Most zoosporangia are formed from June to July. Just when the potato tuber is forming.
Sources of infection
A pathogenic fungus can enter a potato plot in several ways:
- melt water in spring;
- manure from animals fed raw potato fruits;
- through instruments used in the quarantine zone;
- gardener's shoes and clothes;
- the fungus is carried by insects and earthworms;
- diseased potato tubers acting as planting material.
Earthworms are able to live deep in the layers of soil. They act as the main carriers of the fungus. The causative agents of the disease are found at a depth of 50 cm from the surface of the earth. Such cases occur quite often.
The intracellular organism that causes the disease is highly resistant to external conditions. That is why the source of infection can be stored in the ground for 30 years. Dry weather slows down the development of the fungus; some zoospores die as a result of lack of moisture. Due to its vitality, the fungus is dangerous and harmful to potatoes.
Fighting methods
If at least one infected tuber is found on the site, you should immediately notify the plant protection inspectorate. To prevent zoosporangia from getting into manure, diseased potatoes are not fed to animals. Bushes that are affected by cancer are burned along with the tops and tubers.
To get rid of them, they throw them into a deep hole, sprinkling bleach on top.
Diseased root vegetables do not pose a danger to humans, but still they should not be eaten.
Agricultural technology
Every year, in the spring, part of the sporangia becomes active. As a rule, only 30% of pathogenic fungi can withstand winter cold.The essence of agricultural techniques is to open as many cysts as possible. Zoospores that do not find a host die.
To achieve this, use the following methods:
- In the spring, before planting potatoes, fertilize the area. At least 300 kg of manure is used per 1 hectare of land. Disinfection of soil in a greenhouse occurs under the influence of urea. For 1 sq. m is 1.5 substances.
- The plot of land where potatoes grew last year is planted with corn. The root system of the crop secretes a special substance that promotes the release of zoospores. Legumes and rye are considered good soil “cleaners.”
- Planting potato varieties resistant to fungus.
In fact, vegetables are highly susceptible to the effects of zoospores. The affected cell is deprived of the ability to feed the parasite and dies over time. The tissue around it hardens, forming a pustule that contains the dead pathogen. Healthy tissue pushes out the pustule, and the wound heals.
The soil can be completely cleared within 6 years by planting potato varieties that are not susceptible to fungal attack. At the same time, the variety is changed every 4 years to eliminate the possibility of potato cancer adapting to it. It is under no circumstances recommended to sow infected areas with Blue-Eyes and Lorch. They have special sensitivity to the pathogen.
Chemistry
Before planting the planting material, it is soaked in a 0.5% Benomyl solution, another name is Benleint. As an alternative, take a 1% solution of Fundazol. To destroy the source of infection, the ground is watered with pesticides. For 1 sq. m take 20 liters of Nitrophen.
Such actions represent a real chemical operation that should only be performed by a specialist.After applying chemicals, the land is unsuitable for growing any crops. Potatoes or any other vegetable are planted after 3 years. This method of fighting fungus is considered the most extreme of all existing ones.
Prevention
Disinfecting an area is a difficult process that requires time and effort. To avoid contamination of a land plot, you must:
- Remove weeds from the potato bed and around the area.
- Maintain crop rotation, not planting crops in the same place every year in a row. You can plant the vegetable in the same place after 4 years.
- Do not buy planting material in the place where the infection occurred. The same goes for manure.
- Do not plant any crops that belong to the nightshade family close to potato beds.
- If you still cannot avoid infection, plant cancer-resistant crops the next season.
The fungus that causes potato cancer is incredibly resilient. Not every living organism has such properties. For this reason, experts do not recommend planting potatoes of the same variety in the area where the infestation occurred.
Be sure to use different planting material. The agricultural crops market offers a wide range of potato varieties that have good protective properties of the immune system.
Gardeners who have had to deal with potato cancer should adhere to the rules of combating the disease. Under no circumstances should you use chemicals yourself. Especially when it comes to garden or summer cottage plots. The procedure for eliminating fungus is carried out exclusively by experienced people.The fungus that provokes the development of potato cancer is quite dangerous and requires immediate action on the part of humans.
