For cabbage diseases we do not mean the unimportant health problems, but the diseases that affect vegetables belonging to the cabbage group, family of Brassicaceae. A clan, that of the cabbages, which counts numerous traffickers including caterpillars, mushrooms, aphids and so on. So let's see how to protect the crop. Focusing on the biological approach to the prevention and treatment of diseases.
The cabbage diseases the main ones are cabbage and cabbage hernia. Cavolaia is not the name of the disease, but that of the butterfly that deposits its eggs on the leaves of the cabbage generating the caterpillars that devour them. The cabbage hernia, on the other hand, is a fungus.
Between cabbage diseases, the cabbage is the most infamous. In fact, it can wreak havoc by turning a cabbage into a Swiss cheese (in the sense of the holes) and making it perish. Victims of the cabbage are all vegetables of the cabbage group. A very varied group that includes very different vegetables: cabbage, savoy cabbage, Chinese cabbage, Brussels sprouts, cauliflower, broccoli, broccoli and turnip greens.
The cabbage butterfly is recognized by its creamy white color with black wing tips. From the yellow eggs deposited on the underside of the leaves, caterpillars emerge within 1-2 weeks and at that point the raid begins. The caterpillars of the greater cabbage are light green with black dots, those of the lesser cabbage are smaller and pale gray. Both devour the cabbage leaf up to the midrib, the only part that remains intact.
The first natural defense against cabbage is the manual collection of eggs and caterpillars, a very demanding activity that is often not enough to solve the problem. As a prevention, intercropping with tomatoes or celery and periodic spraying with tansy infusion or wormwood infusion are effective. For biological control, preparations based on work very well Bacillus thuringiensis and they are harmless to other living beings.
Bioinsecticide powder based on Bacillus thuringiensis
Liquid bioinsecticide based on Bacillus thuringiensis
It looks like a curse but it is a mushroom, the Plasmodiophora brassicae. A very insidious fungus because its spores survive in the soil for years. Cabbage hernia infestation manifests itself with tumor-like growths on the roots (similar to hernias). Affected plants weaken until they perish.
Prevention against this cabbage disease starts from the ground. Acidic and wet soils favor the proliferation of cabbage hernia: therefore the first thing to do is an assessment of the pH of the soil to create a neutral environment with a pH of around 7 as much as possible.
Soil pH meter
To make an acidic soil more alkaline and increase its pH (alkalinization), wood ash (abundant) or calcium carbonate can be added to the earth (120 gr / m2 for a sandy soil, 300 gr / m2 for clayey soil, 750 gr / m2 for peaty soil). Keeping in mind that several treatments are required to complete the alkalinization of a soil.
Prevention against cabbage hernia is done by adding calcareous algae among the Brassicaceae plants in cultivation. An effective measure is to dip the roots of the plants in horsetail and clay macerate before burying them. Also additions of lithotamnio can be used while for fertilization fresh manure should be avoided.
There is nothing else to do. In fact, we are talking about one cabbage disease which may not completely kill plants, sometimes only weakens them and slows down their growth, but there are no effective preparations for direct control. Furthermore, the spores remain active for a long time in the place where infected cabbages have been grown and it is not recommended to plant more cabbages for at least 4-7 years.