First, the harm symptoms: only harm the roots, the lesions form a tumor-like root knot. The beginning of the root knot is white, and the surface is smooth. Afterwards, it gradually turns brown due to the compound infection of certain pathogens in the soil. Severe main roots and lateral roots were covered with worms, which were connected in beaded shapes. The entire root system was swollen and deformed, forming a cluster of roots or chicken paws. The roots eventually rotted and the plants withered. During onset, the growth of the shoot was slow, the growth was weak, and the symptoms of lack of fertilizer and water were scarce. The plants were short and the leaves were yellow. The results were small and small, and the whole plant gradually wilted when severe. Second, control methods: 1, a reasonable rotation. The use of immunization or high resistance crop rotation for more than one year has a significant effect. Rotate with rice or aquatic crops for better results. 2, remove the sick and weeds. The root of the disease is the place where the pathogenic nematodes live after the season. After harvest, they should be cleared as quickly as possible and burned in a concentrated manner to reduce the sources of infestation early in the year. At the same time, we must remove the host weeds and reduce the population density in the field. 3, pharmaceutical treatment of soil. Before sowing or planting, according to the nature of the pesticide, 1.8 to 0.5% of avermectin emulsifiable concentrate (avermectin) EC may be applied to the seedbed uniformly, or applied to the planting ditch or planting point and then sowed. Colonization. In the early stage of disease, use 50% phoxim EC 1000 to 1500 times, or 90% trichlorfon 800 to 1000 times to irrigate the roots. Fill each well with a good 500 ml of liquid and re-irrigation at intervals of 10 to 15 days. This time, it can effectively control the occurrence of root-knot nematode disease. ZHANGJIAGANG DINSHENGLIN TRADING CO.,LTD , https://www.dslhouse.com