Identification methods and control measures for ginger blast

Ginger blast, also known as ginger rot or bacterial wilt, is the most damaging disease in ginger production, generally causing 20-30% losses, and in severe cases destroying the entire crop, and it continues to cause damage during storage, leading to rot.

This disease can affect stems and leaves, but mainly damages the underground rhizome. It usually occurs first at the stem base near the ground and the upper half of the underground stem; the lesions are initially water-soaked, dull dirty brown, and the internal tissue gradually softens and rots, leaving only the outer skin. Pressing the diseased part by hand can squeeze out a dirty white, foul-smelling fluid; roots, when affected, also become yellow-brown and rot. After the rhizome is damaged, the aboveground stems turn dark purple, the tissue gradually turns brown and rots, the leaves wilt and curl, and the plant may even completely wither and die. If a diseased stem or underground stem is cut crosswise, the vascular bundles can be seen turning brown in a ring, and squeezing by hand will release dirty white bacterial ooze from the vascular bundles. The pathogenic bacteria mainly overwinter in the soil with diseased ginger seed and other field hosts and their diseased residues. Infected ginger seed is the most important source of primary infection, and if introduced, it can cause disease in new areas. When infected ginger seed is sown, or during the growing period, the pathogenic bacteria in other hosts, diseased residues, and soil can invade through natural or mechanical wounds on the ginger epidermis, and disease develops under suitable conditions. The bacteria can also spread through irrigation water, rainwater, or insect pests for secondary infection. A soil temperature of 25-30°C is most favorable for disease development. High temperature, frequent rain, and humidity, especially sudden clearing after heavy rain, may cause severe outbreaks of ginger blast. In addition, low-lying terrain, flood irrigation, and continuous cropping or adjacent cropping with solanaceous vegetables also result in more severe disease.

The control of ginger blast should primarily rely on disease-control measures through strengthened cultivation management, combined with integrated control using chemicals.

1. Select healthy ginger seed from disease-free fields or disease-free plants, and cull again before sowing.

2. Rotation can be carried out with rice or alliums.

3. Ginger seed treatment: before sprouting, fumigate the seed with formalin solution at 1:100 for 6 hours, fully air it out to dissipate the odor, and then sow; or soak the seed with agricultural streptomycin at 500 units for 24 hours.

4. Strengthen management: deep plow and sun-dry the soil on high beds, and apply high-quality organic base fertilizer; prevent flood irrigation and continuous-flow irrigation. When diseased plants are found, pull them out immediately, and sprinkle a small amount of lime into the diseased holes to prevent the spread of bacteria;

5. Chemical control: preventive application must be carried out before disease onset, and options include Kejunkang, copper oxychloride, agricultural streptomycin, and Xiaojunling.