Control of root rot of papaya seedlings

Papaya is a subtropical crop, which is raised and transplanted. The analysis shows that the main causes of root rot at seedling stage are stagnant water in seedling bed after rain, high concentration of fertilization at seedling stage, invasion of nematodes and root rot pathogens. Prevention and control measures: 1. The root system of papaya should breathe in the soil. during anoxic respiration under anoxic conditions, the biochemical reaction inside the roots produces methanol (alcohol). Due to alcoholism, rotting roots occur, this phenomenon is mostly caused by stagnant water in the seedling bed or soil consolidation resulting in lack of oxygen in the soil. the drainage ditch between the bed and the bed should be opened to prevent the seedling bed from flooding after rain. 2. The root system of papaya seedlings is young, and it is better to apply fertilizer at a dilute concentration. The concentration is too easy to cause the young roots not to be absorbed. On the contrary, the free water in the young root cells permeates and dies, causing rotting roots. That is, as farmers often say, "crops are burned to death by fertilizer." 3. After the roots of papaya seedlings were damaged by nematodes, the internal tissue of young roots was destroyed, which hindered the absorption and transport of nutrients to the plants. when found, 70% chlorothalonil 600 times solution or 70% chlorothalonil 800 times solution could be sprayed. 4. The occurrence of root rot is a disease that causes root rot of seedlings. When it occurs, the mu is sprayed with 25% trimethoprim, 5 ml, 6 g and 500 mol ·m-1 water.