We will show you how to recognize the symptoms of clubroot and how to successfully prevent and combat it.
Symptoms of Clubroot
In addition to insects, our beloved cabbage is unfortunately also affected by a fungal disease that is very difficult to combat. Clubroot (Plasmodiophora brassicae) is a dreaded disease affecting all cabbage plants (Brassicacea). An infected cabbage plant can be recognized by the fact that the plant initially grows poorly and later develops wilted leaves, which also turn yellow. If your cabbage then also sags on warm days and lets the leaves droop, you should dig up one of the diseased plants. An infestation with the fungal pathogen is present when the roots are bulbous and thickened. To avoid confusion with the infestation of the cabbage weevil, we recommend cutting off a thickened root. If the root is white and not hollow, it is most likely clubroot.
Pathogen
The clubroot (Plasmodiophora brassicae) is a crop rotation disease that is feared in agriculture. The slime mold feels very comfortable, especially in warm and wet soil. If there is also an acidic pH value, the clubroot has perfect living conditions. The disease is also dangerous because of its very hardy spores. As a rule, the spores can survive in the soil for many years. Unfortunately, the disease can break out again after a long break in cabbage cultivation. The unwelcome pest nests in the roots of the cabbage plants and releases hormones that lead to the typical thickening of the roots. These tissue growths are used by clubroot as a source of food. Because of the severe damage to the roots, the plant cannot take out enough water and nutrients. The disease spreads through many routes and is difficult to monitor because the slime mold cannot be seen with the naked eye. He even has spurs with so-called flagella. With this thread-like appendage, the spore canmove yourself.
Clubroot: Preventive Measures
In order to prevent clubroot disease from occurring in the first place, you should take a closer look at its habitat. So the earth! If you have a choice between sandy soil and heavy loamy soil for cabbage cultivation, go for the light sandy soil. The soil dries faster and offers the clubroot poor living conditions. However, the low nutrient content of sandy soils should be taken into account. So don't forget to fertilize, as cabbage is a heavy feeder. The second important aspect is the pH value. Unfortunately, this cannot be seen with the naked eye, but can be determined with a pH test. If the pH you measured is below 6, then you should definitely consider liming the soil. Not only does clubroot then have almost no chance, but liming has many other positive effects on the soil. This includes, for example, better nutrient availability.
In addition to the living conditions of the fungus, crop rotation is a central point that must be observed. Ideally, a cabbage patch should only be planted with cruciferous vegetables again after 3 to 5 years. But we also know that this is mostly just wishful thinking. Most vegetable gardens just don't have enough space to do this crop rotation. However, there are tools to ensure that the permanent spores of clubroot are broken down more quickly in the soil. In addition to green manure, adding humus can vitalize the soil. As a result, the natural microorganisms become more active and break down clubroot spores more quickly. In any case, infested cabbage plants and harvest residues belong in the residual waste and must not be put on the compost. There, with a bit of bad luck, the permanent spores can survive for up to 10 years.
Control of clubroot
Direct control of clubroot with pesticides is not possible in the private sector. And that's just as well! Drugs against clubroot are extremely harmful to aquatic organisms and it is not for nothing that these active ingredients are not approved in Germany. A very complex form of control is soil steaming. The high temperatures kill the fungus. However, this form of plant protection is very energy-intensive and also hardly feasible for us hobby gardeners. That is why it is all the more important to take preventive measures.
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