Ginger white star disease

(pathogen name) Septoriazingiberis

(host crop) ginger.

(disease diagnosis) is a damaged leaf. Leaf disease, at the beginning of the emergence of water-like spots, gradually expanded after the disease spot nearly fusiform, light brown, the center gray-white, the later disease spot extended up and down to grow spots. There are many small black spots scattered on the disease spot. In severe cases, the disease spot can be longitudinally cracked and the leaves withered. The pathogen is Cercospora ginger. Conidia epidermis or on both sides of leaves, globose or oblate, dark brown, endophytic with many conidia. Conidia linear, nearly straight or curved, colorless, with 2-6 septum, mostly 3-4 septum.

The pathogen overwintered in the soil with the remains of mycelium and conidia. In the following year, the infection of conidia produced by overwintering bacteria caused disease in the field. After the disease occurred, the conidia were reinfected by wind and rain, which led to the rapid expansion and spread of the disease and aggravated the disease. The climatic conditions of high temperature, humidity and continuous rainfall are beneficial to the occurrence and development of the disease. In addition, continuous cropping, low-lying planting land, poor soil, insufficient fertilizer or too much nitrogen fertilizer are all conducive to the disease.

(prevention and control measures) (1) choose high dry land and fertile soil for planting. Low flat land should be cultivated with high ridge or high border, and do a good job of deep trench drainage. (2) adequate application of rotten manure, timely and appropriate amount of topdressing. Don't use too much nitrogen fertilizer, and pay attention to increasing the application of phosphorus and potash fertilizer, especially potash fertilizer. (3) Scientific irrigation, drainage after rain and reduction of field humidity. (4) it is not suitable to work in the field after rain or when the dew is not dry, so as to reduce the chance of disease transmission and reduce the incidence of disease. (5) spraying medicament control in time at the initial stage of the disease, the medicament can choose 30% Ludebao glue suspension 300 times liquid, or 30% succinic acid copper acid wettable powder 400 times liquid, or 64% poison alum wettable powder 500 times liquid, or 80% Wanlusheng wettable powder 800 times liquid, or 68% Dili wettable powder 800 times liquid, or 80% dimethrin wettable powder 500 times liquid.