Control methods of black spot of cabbage

Cabbage is a kind of vegetable that we often eat in our daily diet, which is often harmed by diseases and insect pests in the production process, resulting in serious damage to its quality, of which black spot is one of the more serious. So how to prevent and cure the black spot of cabbage? Let's get to know it with the editor.

1. Disease hazard

Cabbage black spot mainly harms plant leaves, which occurs on outer leaves and outer globular leaves. Small black-brown spots appear at the initial stage of the disease, which gradually expand, the spots have concentric rims, the edges are dark, the peripheral yellow halo is obvious, and black mildew layers can be formed when the disease spots are wet. The diameter of the spot can reach 4-10 mm, or even larger. In severe cases, the disease spot is densely covered with leaves, and sometimes several disease spots will synthesize large plaques, which are very easy to rupture or fall off and perforate normally. The disease spot on the petiole is oval or nearly fusiform, slightly sunken, and the spot also has concentric wheel pattern and long black mold.

2. The cause

The disease is mainly caused by Alternaria brassica infection, which overwinters with mycelium and conidia on seed plant, soil, seed surface and diseased body. It became the source of primary infection in the second year, and the infection harm of conidia produced by overwintering pathogen in the following year. After the onset of the disease, the conidia produced by the disease department will be spread by wind and rain and repeated infection, resulting in the spread of the disease. The temperature is 17 degrees and the relative humidity is 75% Mel. 85% is conducive to pathogen infection.

3. Prevention and control methods

① agricultural control

Be sure to disinfect the seeds before sowing, clean the fields after harvest, and dig deep into the soil. In seriously ill plots, you can rotate with non-cruciferous vegetables for more than two years. Soil testing formula fertilization, pay attention to the effective use of nitrogen, phosphorus and potassium compound fertilizer, enhance the disease resistance of plants, high ridge cultivation can be used to improve soil heat absorption and soil moisture conservation capacity.

Chemical control of ②

At the initial stage of the disease, germicidal alum, chlorothalonil, carbendan, mancozeb and prohydantoin can be used to spray water every other time. In order to ensure the prevention and control effect, brassinolide regulator can be added to save medicine and achieve the effect of drug reduction.

The above is the introduction of the prevention and control methods of cabbage black spot, hope to help you, want to know more related knowledge, please follow us.