Control Methods for Root-Knot Nematode Disease in American Ginseng

In recent years, more and more farmers have chosen to grow American ginseng to increase their income. American ginseng is a common Chinese medicinal herb with large market demand and high planting returns. At the same time, because American ginseng has a long growing cycle, it is often vulnerable to root-knot nematode disease, leading to serious yield reductions.

It is understood that root-knot nematode disease in American ginseng is a disease caused by infection and damage by root-knot nematodes. Root-knot nematodes harm only the ginseng roots. After being damaged, the roots form root knots due to stimulation by secretions from the nematode esophagus. The root knots are initially milky white and relatively firm, and later gradually turn dark brown and often show rotting. Because the roots are damaged, the normal functions of the root system are affected, and the ability to absorb fertilizer and water declines. Affected plants above ground are weak and small, with yellowing and chlorosis of leaves, delayed flowering and early withering, and in severe cases they may even wilt and die.

In addition, when root-knot nematodes infect plants, they cause mechanical damage to the roots. The wounds provide pathways for the invasion of other pathogens in the soil, causing combined infection of root-knot nematode disease with root rot, rust rot and other diseases, intensifying the condition. According to statistics, after damage by root-knot nematode disease in American ginseng, affected fields generally suffer yield reductions of 20%-30%, and in severe cases up to more than 70%.

Root-knot nematode disease is a type of soil-borne disease and can spread through diseased seedlings, diseased soil, water flow, daily farm work and other routes. Once the soil is contaminated, it is difficult to completely eliminate and clear it. At the same time, because American ginseng is a perennial herbaceous plant with persistent roots, it must grow in the soil for 3 years or longer before it can be harvested. Therefore, in the planting and production of American ginseng, controlling the population of root-knot nematodes in the soil, and even ensuring that the soil is healthy and clean, is the foundation for the normal growth and development of American ginseng. Experts say that in the early stages of controlling root-knot nematode disease in American ginseng, farmers can use conventional agricultural and physical control methods, such as cultivation with disease-free soil and disease-free seedlings, crop rotation to prevent insects, and deep plowing of the soil.

In addition, experts remind farmers that spring is approaching, which is exactly the active period when root-knot nematodes resume activity and attack new roots. At this stage, when applying spring fertilizer to promote new roots, farmers can combine nematicides to control root-knot nematodes in the soil, laying the foundation for the recovery of the American ginseng root system and promoting root growth.

Among the nematicides used in the past, most products caused relatively heavy environmental pollution and were unsafe for humans and livestock, and most are now banned or restricted. Therefore, experts recommend that farmers can choose Yinghui nematicides. Products in the Yinghui nematicide line, such as Ligensha, Yinghui Kuaixian, Tiandixian and Wuxian, are available in both granule and liquid formulations, suitable for use at different growth stages of American ginseng. These agents are all biological pesticides, with significant control efficacy and safe, pollution-free use. Farmers can apply Yinghui nematicide granules by furrow application, hole application or broadcasting over the whole field before transplanting American ginseng or at the current time of applying spring fertilizer, and the duration can last as long as 2-3 months. If American ginseng is damaged during the growing period and the damage is severe, Yinghui nematicide liquid formulation can be diluted with water for root drenching or flushing application to achieve a very good control effect.