I would hate to have a perfect field full of fresh cabbages for starters then all of a sudden have them full of spots after infections affect them or they become ridden with pests. Thus, rendering them unfit for consumption, unpleasant to the eyes, leading to waste of time, resources and energy. Ensure to rotate crops to avoid build-up of diseases and pests. Always invest in the seedlings that are pathogen free and resistant varieties. In any case, you sow what you plant. So give your plants a good head start and increase their chance of survival.
Exploring the diseases and pests related to cabbages
Look out for symptoms on affected areas i.e. the roots, leaves and stem. Some of the most rampant diseases and pests affecting cabbages include,
Insects (black, white, red or green in colour) that cause curled yellow leaves while also exuding a honeydew substance. They affect the leaves. Use aluminium foil to control. Put a layer of the foil under the plants to reflect light on the underside of leaves. This makes the environment undesirable for the aphids. Other control measures include insecticidal soaps or oils such as canola or neem oil are highly advocated. Use strong streams of water for sturdy plants. If only a few plants are affected, prune them out and only use insecticides if the infestation is very high.
Finding large or small holes in the leaves? Well, this may be because of these pale green caterpillars. They are mostly found on the underside of leaves. Eggs are laid close to the leaf margin. Control measures include application of insecticides, and biological controls such as spraying with Bacillus thuringiensis.
Cutworms: These larvae are active during the night while they hide during the day at base of plants or in debris.
The larvae have a distinct characteristic of curling up forming the letter c when disturbed. They may exhibit a variety of colours as well as patterns. Ensure to clean all debris after harvesting or two weeks prior to planting. Especially if the previous crop was, another host crop for example a leguminous cover crop. Some control measures that can be exercised are handpicking larvae after dark, fitting foil collars around the stems of the cabbage to prevent larvae from severing the plants. Apply appropriate insecticides for inorganic farms.
Some diseases to look out for include;
The symptoms start as yellow lesions on the leaf margins that form v- shapes. Another major symptom is blacked veins on the cabbage. Bacteria that is spread via infected seed causes it. As well as, insect movement and splashing water. Practice crop rotation and good sanitation. Invest in plant resistant varieties and control cruciferous weed species, which may be bacteria reservoirs. Plant pathogen free seed.
Caused by a fungus. It can be difficult to distinguish from nematode damage. Symptoms include slow growth, stunting, yellowish leaves wilted through the day and swelling on the roots. Fungus can survive in soil for up to ten years. Spread is through contaminated irrigation water and soil to unaffected areas. Liming the soil may reduce fungus sporulation. Plant only certified seeds. Elimination of the fungus is unfeasible. Rotation of the crops does not provide control.
Death of seedlings after germination is one of the symptoms. A constricted and twisted stem is another symptom. For older cabbage, brown patches on leaf underside that cause wilting and drooping are a wake-up call. Apply fungicides to kill off fungi. Delay planting until the soil warms up. Another alternative option is shallowing seeds.
The emergence of this is favoured by the dry season,, low humidity as well as rainfall. Small, white patches that form a dense powdery layer that coats leaves causing the leaves to become chlorotic and drop from the plant characterize powdery mildew. To solve this problem, plant resistant varieties, clear garden of all debris after harvest, rotate crops and remove weeds. Sulfur sprays, vapors and dusts application can help in control.
Watery soft rot.
Fungus causes the head to become soft and slimy. The stem of the base spreads upwards successfully killing leaves. Frequent rainfall that keeps the soil close to saturation is the cause. Rotate crops with non-host crops every 3 years. Severe infestation requires application of appropriate fungicide.