A Detailed Guide to the Latest Control Methods for Cabbage Black Spot

Cabbage is a vegetable commonly eaten in everyone's daily diet, and during production it is often harmed by pests and diseases, causing its quality to be severely damaged, among which black spot is one of the more serious ones. So how should cabbage black spot be controlled? Follow the editor to learn about it together.

1. Disease Damage

Cabbage black spot mainly harms the plant leaves, occurring on the outer leaves and outer layer of head leaves. In the early stage of the disease, small dark brown spots appear and gradually expand. The spot surface has concentric rings, the edge is darker in color, and the outer yellow halo is obvious. When humid, a black mold layer forms on the diseased spots. The spots can reach 4-10 mm in diameter, or even larger. In severe cases, the spots densely cover the leaves, and sometimes several spots merge into large patches. The spots very easily rupture or fall off, forming normal perforations. On the petioles, the spots are oval or nearly spindle-shaped, slightly sunken, and the spot surface also has concentric rings and long black mold.

2. Causes of Occurrence

This disease is mainly caused by infection by the fungus Alternaria brassicae. The pathogen overwinters as mycelium and conidia on seed plants, soil, seed surfaces, and diseased residues. It becomes the primary infection source for the next year, and the conidia produced by the overwintering pathogen the following year cause infection and damage. After the disease occurs, the conidia produced on the diseased parts spread through wind and rain, causing repeated infection and leading to expansion and spread of the disease. At a temperature of 17 degrees and relative humidity of 75%-85%, infection and disease development by the pathogen are favored.

3. Control Methods

① Agricultural control

Before sowing, the seeds must be disinfected. After harvest, clean the field and deep plow the soil. In plots with severe disease, rotation with non-cruciferous vegetables for more than two years can be carried out. Use soil testing and formula fertilization, pay attention to the effective use of nitrogen, phosphorus, and potassium compound fertilizer, and enhance the plant's disease resistance. During cultivation, high-ridge cultivation can be used to improve the soil's heat absorption and moisture conservation capacity.

② Chemical control

In the early stage of the disease, you can use carbendazim, chlorothalonil, captan, mancozeb, and iprodione with water spraying at intervals. To ensure the control effect, brassinolide regulators can be added, which can save pesticide and achieve the effect of reducing pesticide without reducing effectiveness.

The above is an introduction to the control methods for cabbage black spot. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.