Soil nematodes: What are they, damage they can cause and control

Soil nematodes are microscopic

There are many pests and diseases that can affect crops. But nevertheless, among the most annoying and difficult to eliminate parasites are soil nematodes, that are capable of destroying entire fields of cultivation.

If you want to know more about this pest, I recommend that you keep reading. We will explain what soil nematodes are, the damage they can cause and how to control them.

What are soil nematodes?

Soil nematodes are very harmful to plants

Soil nematodes are very harmful to plants.

First we are going to explain what are nematodes ground. They are parasites whose development takes place in the soil and which affect plants. These microscopic worms are between 0,1 and 3 millimeters in size. To feed, they pierce the plants and suck the nutrients from the roots and the cells of the same. As a consequence, the affected vegetables are more exposed to incidences from bacteria, viruses and fungi.

Especially for farmers they are a very big problem. Soil nematodes can cause really serious damage to crops, even going so far as to spoil an entire harvest. If this problem is not prevented or treated in time, the economic losses can be very high. Various sources estimate that soil nematodes reduce agricultural production worldwide by between twelve and twenty percent each year. This equates to about 135 billion euros per year.

Damages that can be caused by soil nematodes

Once a plant-infecting nematode accidentally reaches a field, it can take several years for the population of the field to be large enough to cause visible symptoms in vegetables. This is because these parasites move very slowly through the earth. However, its spread is very easily carried out by moving the infested soil. They can also infest parts of plants and even objects, such as agricultural machinery and tools, planting material, etc.

When the infestation of soil nematodes has spread enough to cause visible abnormalities in plants, the following will begin to occur symptom:

  • Shortening and swelling of the roots
  • Appearance of galls or knots on the roots
  • Chlorosis on the leaves that gradually turn yellow
  • Performance decline
  • Plant swelling
  • Delayed or early maturity of the fruits
  • Black spots on the roots
  • Delay in the appearance of outbreaks
  • Multiple plants with symptoms in the same crop

Basically, nematodes in the soil cause the roots to rot and weaken the plant by absorbing its nutrients. Once the roots are gone, they continue digging the earth until they reach the next healthy roots. Apart from the important damage that these parasites cause to vegetables, they also increase the risk that they will contract infections caused by bacteria, viruses and fungi.

How to control soil nematodes?

It is difficult to combat soil nematodes

It is difficult to combat nematodes in the soil

Unfortunately, once the land is infested with soil nematodes, there is not much we can do. As they are parasites that live under the ground, it is especially difficult and complicated to combat them. In addition, its tiny size also complicates this task considerably. However, we do have an option to eliminate nematodes in an ecological way.

Nematodes can prevent a palm tree from dying from paysandisiaNematodes can prevent a palm tree from dying from paysandisia

One of the strategies we can try to get rid of these annoying parasites is solarization or biosolarization. It is the most effective method, but requires the field to run out of plants to increase its effectiveness. Basically it is about increasing the temperature of the soil until destroying the pathogens. To do this, the ground is covered with a transparent plastic for at least four weeks in summer, specifically during the period of greatest solar radiation.

Another way to fight soil nematodes in an ecological way is introducing natural predators of them, such as other bacteria or fungi. This method is less effective than the previous one, but it helps to control these parasites.


As they say, “prevention is better than cure.” Thus, the best we can do to use preventive strategies to prevent our crop from being affected by soil nematodes. There are several techniques that we can apply to achieve good prevention:

If you have already had problems with these annoying parasites, you can leave us your experiences in the comments.

Soil nematodes: What are they, damage they can cause and control

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