The latest control methods of black spot in cabbage

Cabbage is a kind of vegetable that we often eat in our daily diet. It is often damaged by pests and diseases in the production process, resulting in serious damage to its quality, among which black spot disease is one of the more serious ones. So how to prevent cabbage black spot disease? Let's learn about it together with Xiaobian.

1. Disease hazard

Cabbage black spot mainly damages plant leaves, occurs on outer leaves and outer bulbs, appears black-brown spots in the early stage of the disease, gradually expands, the spots have concentric ring patterns, the edge color is dark, the outer yellow halo is obvious, when wet, the spots will form black mold layer, the diameter of the spots can reach 4-10 mm, or even larger. When the disease is severe, the leaves are densely covered, sometimes several disease spots will synthesize large patches, and the disease spots are easy to rupture or fall off normal perforations. Lesions on petioles were oval or nearly fusiform, slightly concave, with concentric rings and long black mold on the surface.

2. Causes of occurrence

The disease was mainly caused by Alternaria brassica infection. The pathogen overwintered as mycelium and conidia on seed plants, soil, seed surface and diseased bodies. It becomes the primary infection source in the second year, and the conidia produced by overwintering pathogen in the next year infect and harm. Conidiospores produced by infected parts will spread by wind and rain after infection, and repeated infection will cause the disease to expand and spread. The temperature of 17 ℃ and the relative humidity of 75%-85% are conducive to the infection of pathogenic bacteria.

3. Prevention and control methods

① Agricultural control

The seeds must be disinfected before sowing, the fields cleaned after harvest, and the soil deeply turned. In the seriously ill plots, rotation with non-cruciferous vegetables can be carried out for more than two years. Soil testing and formula fertilization, pay attention to the effective use of nitrogen, phosphorus and potassium compound fertilizer, enhance the disease resistance of plants, cultivation can be adopted high ridge cultivation, improve the heat absorption and moisture retention capacity of soil.

② Chemical control

At the beginning of the disease, anti-virus alum, chlorothalonil, captan, mancozeb and diaphanil can be sprayed at the end of every interval. In order to ensure the control effect, brassinolide regulator can be added to save medicine and achieve the effect of reducing medicine without reducing it.

The above is an introduction to the control methods of cabbage black spot disease. I hope it can help you. If you want to know more about it, please pay attention to us.