Many gardeners who grow their own seedlings have encountered the phenomenon popularly called \"blackleg\". It is a disease associated with blackening and rotting of the root neck at the junction with the stem. The disease is predominantly fungal, insidious and can eventually lead to the death of all seedlings. However, similar signs are possible with bacterial or viral lesions of seedlings. Therefore, preventive measures capable of preventing black leg disease play an important role in the fight against it in the first place.
- General information
- Preventive measures
- Methods for fighting black feet
- Video on, How to combat blackleg in seedlings
Darkening and rotting of the root neck in seedlings or blackleg is a fairly common pathology to which plants in the cruciferous and nightshade family are most commonly affected:
In addition, many flower seedlings are susceptible to black feet.
It is usually active from the time the seeds germinate until 2-3 complete leaves have formed. Then, as the seedlings develop and acquire a certain immunity, the possibility of black feet is reduced, although it cannot be ruled out completely.
In most cases, the main causes of black leg infestation of seedlings are due to violations of one or more agronomic practices, which include:
- use of contaminated soil;
- excessive watering;
- overly dense planting (lack of air circulation, reduced light exposure, moisture retention);
- insufficient light exposure;
- significant temperature fluctuations;
- high humidity combined with elevated temperature;
- overuse of nitrogen-containing fertilizers;
- lack or irregular ventilation;
- use of old growing boxes and containers (untreated).
The causative agents (fungi of the species Olpidium, Pythium, Rhizotia and Fusarium) live in the top layer of soil, where they feed on various organic residues. However, under favorable conditions (considerable humidity and temperature within the range of +22-28°C) they also move to the root neck of plants. Thus the stem begins to darken and thin at the place where it emerges from the ground, then turns black and falls off. As a result, no nutrients get from the root system to the above-ground parts of the plant, resulting in its final death.
The disease is quite fast spreading and quickly passes to healthy seedlings. The fungus is tenacious and can survive in temperatures ranging from + 2°C to + 33°C for several years.
If effective measures are not taken in time, the pathology can spread to all seedlings in just days, eventually leading to loss of all seedlings.
The main remedy against black leg on seedlings is to take preventive measures against the development of this disease as well as to observe the requirements of agricultural technology.
- Purchasing quality seeds that are relatively resistant to this disease from proven producers. However, no variety of various crops currently has absolute 100% resistance to the disease.
- Strict adherence to the seed sowing instructions.
- Use planting containers (pots, tablets, etc.) made of peat. It has been noted that seedlings grown in such containers without soil are practically not subject to various rotting phenomena. Some experienced gardeners even use toilet paper rolls for similar purposes.
- Disinfecting the soil. The list of popular and effective remedies is quite long:
- перманганат калия;
- «Здоровая земля»;
- «Максим дачник»;
- \"Baikal EM-1\";
- \"Shining\" and others.
Состав and mechanism of action of these drugs are varied, but in the end their use results in the death of pathogens. They should be used strictly according to the manufacturer's instructions. After the application of the above remedies it is advisable to give 2-3 days rest for the soil. This also minimizes the risk of negative effect of substances on seeds.
- Exclude the use of manure in land mixture formation that promotes favorable nutritive environment for various fungi species.
- Use calcined coarse river sand as a top layer to prevent mold and decay processes.
- Use soil with normal acidity as the blackleg pathogens prefer an acidic environment. If the soil is excessively acidic, it is possible to improve it by adding limestone, dolomite flour or wood ash.
- Create a drainage layer in the container for growing seedlings.
- Pre-sowing treatment of seeds from own preparation or those purchased from unknown persons at market. The following preparations have worked well:
- перманганат калия;
- \"Trichoderma Veride\";
- \"Phytosporin-M\" and others.
Способ of the preparation of the working solutions and the treatment times are determined from the enclosed instructions.
As a rule, seeds sold in specialized stores are completely ready for sowing. They have been properly prepared as often shown by their unusual coloration.
- Maintain the optimum watering regime, humidity and temperature recommended for the cultivation of the seedlings of the respective crops.
- Preventing overwatering of the soil.
- Use standing water with a comfortable temperature of +21-25°C for irrigation.
- Regularly aerate the seedlings and remove condensation.
- Use additional light when the daylight hours are short.
- Roeing the ground to allow oxygen access to the root system.
- Timely thinning of seedlings and avoid overgrowth.
- Use Kornevin, Kornestim, Korn-Super and similar rooting stimulants allowing a shorter rooting time when transplanting (picking) seedlings.
Many gardeners advise burning soil in an oven to decontaminate it. The soil is placed in a metal container, steeped in boiling water, and then placed for 30 minutes in an oven heated to 100° C or higher. However, in this case, useful bacteria are also destroyed. To repopulate them, the preparation \"Fitosporin\", which includes soil microorganisms, is well suited.
Dardeners recommend powdering the top layer of soil with ash or crushed charcoal and watering seedlings that are prone to rot with a solution of baking soda (1 tsp per 1 cup of water) as a preventative against rot. The remedy not only has good bactericidal qualities but also helps reduce soil acidity.
The risk of black stem in seedlings is quite high if no preventive measures are taken.
Ways to combat black stem
If black stem infection cannot be avoided, immediate measures must be taken to save the remaining plants. First of all, remove all diseased specimens with a clump of soil in front of them, and then treat the soil and the remaining seedlings. Both proven folk methods and a variety of biological and chemical preparations are possible.
A traditional and often used treatment is a Phytosporin solution (consumption - 100 ml of the preparation per 10 liters of water). The seedlings are not only watered with it, but they are also sprayed from the moment of the formation of two true leaves.
For a similar purpose, 1% solution of Bordeaux liquid or copper sulfate could be used from \"on hand\". After treatment it is recommended to cover the ground with a mixture of crushed wood ash and copper sulfate (one teaspoon of copper sulfate per cup of ash).
Special care must be taken when using potassium permanganate. The solution should be pale pink with a basic substance consumption of not more than 1 g/1 L of water. Otherwise, you can burn the immature roots of seedlings. It is also recommended to pre-water the soil with clean water before applying manganese.
In cases where many affected specimens are found, the healthy seedlings should be unpacked and planted in individual containers with pre-disinfected soil.
To water such crops, an infusion of onion husk, which contains many phytoncides, is useful. To prepare such a mixture, 500 grams of onion husks are needed and 3 liters of warm water are poured over them. After a day's infusion means is ready for use. The frequency of watering is once every four days. The infusion not only destroys pathogenic microbes, but also serves as an excellent growth stimulator.
An even greater disinfectant effect is achieved by a composition using vodka instead of water in the proportion 1 part vodka for 10 parts of onion infusion. Spraying the soil is made 2 times with an interval of 7-10 days.
For the first signs of black leg infestation, ash solution can be helpful. First, a concentrate is prepared: 2 cups of ash per 1 l of boiling water. Before use, the composition is infused for 6 hours and diluted with water in a 1:10 ratio.
Some gardeners use heavily ground egg shells to sprinkle the soil with it, as well as spraying the crop with an infusion of marigold.
The following biological and chemical preparations are effective in controlling blackleg:
- \"Bactofit SP\";
- \"Metronidazole\" (an antimicrobial used to treat humans);
- \"Previcur Energy\";
- \"Fundazol\" and others.
Применять They should be used strictly as directed, They must not be overdosed.
Video on how to fight blackleg in seedlings
Follow these instructions and your seedlings will not have blackleg. The author of the video explained in detail the prevention and treatment of this disease. Присоединяйтесь к просмотру!