Stem blight becomes the cancer of asparagus how to control asparagus stem blight

Asparagus stem blight is widely distributed, harmful and destructive, and is called asparagus cancer. The high incidence in summer often causes the destruction of asparagus in large areas. It has become the main limiting factor for planting asparagus.

Asparagus stem blight

1. Harmful symptoms. The main site of the disease is the stems and branches of asparagus, but not the leaves. In the early stage of the disease, bronze water-stained spots gradually expanded to form a fusiform edge of reddish brown or brown spots; in the middle and later stage, it became grayish brown, slightly sunken, dense black spots, that is, conidium. The disease spot can go deep into the pith and wait around the stem or branch for a week, and the asparagus in the upper part of the disease spot will dry up, lose water and die. The peak period is from July to September.

2. Prevention and control technology

(1) reduce pathogenic bacteria. The disease in the new asparagus field was mild, while that in the old asparagus field was early and severe. The germs in the new bamboo shoot field mainly come from: first, the seed carries the bacteria; second, the wind or Rain Water brings the germs from the old bamboo shoot area. Therefore, the cleaning and disinfection of asparagus field should be done well to reduce the source of infection.

(2) rational fertilization. The amount of organic fertilizer and phosphorus and potassium fertilizer increased, and the amount of nitrogen fertilizer was properly controlled. The suitable ratio of nitrogen, phosphorus and potassium is 1 ∶ 0.6 ∶ 0.8. The application of organic fertilizer can increase the content of organic matter in soil, loosen soil, promote the robust growth of root system, stem and leaf of asparagus, and improve the ability of disease resistance.

(3) Pesticide control. Prevention should be given priority to. After asparagus tender stems are drawn, spray medicine should be applied in time. In spring, combined with clean fields, asparagus roots were irrigated with 50% carbendazim and 300 times of carbendazim. In the initial stage of stem blight from May to June, 80% of Dasheng and 75% methyl thiophanate were sprayed once every 7 to 10 days, and during the peak period of July to September, the asparagus stems and branches of 60cm above the ground were mainly sprayed, supplemented by the upper branches and leaves, and sprayed once after rain. Use the above chemicals alternately to prevent asparagus from developing drug resistance.