What’s Root-Knot Nematode?

Root-Knot Nematodes


Root-knot nematodes are one of the three most economically damaging genera of plant-parasitic nematodes on horticultural and field crops. They parasitic the roots of thousands of plant species, including monocotyledonous and dicotyledonous, herbaceous and woody plants.

They dwell in the soil, attack the roots of the plant to extract water and nutrients. As a result, large galls or “knots” can form throughout the root systems of infected plants. They will bring a lot of damage to plants.

Root-knot nematodes Life Circle: an egg stage, juvenile stages(J1–J4), and an adult stage.

Root-Knot Nematodes Symptoms

Under the Ground

Root-knot nematode symptoms on plant roots are dramatic. However, most diagnostic root-knot nematode damage occurs underground. By identifying these underground symptoms, we can know whether root-knot nematodes have already threat your crops.

The most distinctive symptom of root-knot nematodes infestation is the appearance of galls on primary and secondary roots, which become swollen and distorted with heavy infestations.

symptoms of root-knot nematode
symptoms of root-knot nematode

On the Ground

Besides the symptoms of underground, root-knot nematodes infestation also have other above-ground symptoms. Root-knot nematode damage results in weak growth, a decline in quality and yield of the crop, and reduced resistance to different stresses. Seriously may lead to direct death.

1. Stunted, yellowed, or wilted, and can lead to the premature death of the plant. (Symptoms on tomato)

root-knot-nematodes of tomato

2. A sharp drop in output  (Symptoms on potatoes)

root-knot-nematodes of potato

How to Distinguish Symptoms?

The appearance of the galls on the roots can be confused with nitrogen-fixing nodules commonly found in legumes. However, it is easy to distinguish between them because the nitrogen nodules can be easily wiped off, and the nematode galls cannot be removed.

We can’t be sure that the symptom of the plants is caused by root-knot nematode. We only remove the plant from the soil to examine its roots so that we can determine if it is caused by root-knot nematode.

How to Eliminate Root-knot Nematode?

Although these root-knot nematodes may have problems, they are not uncontrollable. Here are several common kinds of control methods.

Agricultural Control

  • Strengthen inspection and quarantine, and try to reduce or even eliminate the transmission of root-knot nematodes through seedlings, machinery, tools, and other human factors
  • Reasonable rotation can reduce the number of soil nematodes and reduce the occurrence of diseases
  • Treat sick strains thoroughly and fertilize and irrigate rationally
  • Select anti-root knot nematode varieties or choose root-knot nematode rootstock for grafting

Biological Control

The biological preparation has the advantages of excellent compatibility, eco-friendly. Bio nematicides are not easy to produce drug resistance, non-toxic and no side effects, and are harmless to humans and animals. They promote the development of plant roots and grow robust, to achieve the impact of disease prevention and treatment, an increase of production and income. The most representative product is paecilomyces lilacinus.

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