Phytophthora - one of the most dangerous and most widespread diseases of potatoes. Infection occurs through rain water which, flowing down on the infected stalks and leaves, will get to the soil and also during gathering potatoes.
To understand that tubers of potatoes are infected with phytophthora, at once it is impossible, it will become noticeable only 2-3 weeks later after harvesting. On tubers there are firm to the touch, spots kind of pressed. Over time they get inside, than cause rotting. Under favorable conditions the development of disease goes pretty fast. As a result, potatoes removed on storage together with the infected tubers can be also infected. Not to allow emergence and spread of this disease, it is necessary to observe alternation of cultures. Causative agents of phytophthora can be in the soil therefore it is not recommended to grow up 2 years in a row potatoes on one site.
At detection of infection of single plants, the tops of vegetable on them is cut off as low as possible, taken out from the site and dug in or burned. The harvest from sick plants is dug out in the last turn not to cause infection of healthy potatoes. Tubers for the subsequent landing select only healthy, without symptoms of various diseases. If under one bush there is at least one sick tuber, then and all potatoes which are dug out here cannot be used as planting stock.
At mass infection with phytophthora before harvesting it is recommended to spray plants with solution of copper vitriol. Further the tops of vegetable needs to be cut off, taken out from the site and to burn. On the infected soil it is possible to grow up potatoes only in several years.
The dug-out harvest should not be removed on storage at once, it is better to allow it to dry out well, and then to make selection of the infected tubers. They are also taken out out of borders of the seasonal dacha and dug in more deeply to the soil, having filled up them with chloric lime. Without these actions sick potatoes will become disease source.
When landing in the spring of tubers, even slightly struck with phytophthora, there will be soil infection. Together with growth of potatoes will begin the development and the mushroom striking young sprouts and the soil. Therefore to grow up healthy harvest of potatoes, it is necessary to select planting stock carefully.