Mention nematodes and farmers will shudder and many gardeners will cringe.  Nematodes, by and large, get a bad rap. 

Nematodes are classified as insects.  They have a tubular body and a digestive system with openings at both ends. 

Because they are not easily visible being microscopic in most instances, it is hard to distinguish one variety from another.  It is estimated that there can be more than a million nematodes in every square meter of soil on earth.  Nematodes play an important role in the soil ecosystem and without them, life on earth would probably be unsustainable.

The Good and The Bad

As simple gardeners, we can classify nematodes in two categories, beneficial and destructive.  Some nematodes are harmful and feed on living plants.  Others are free-living and feed on organic debris, microorganisms, and other nematodes. Some beneficial nematodes help control insect pests such as armyworms, cabbage loopers, potato beetles, cutworms, and grubs.  Nematodes can even help control pests such as fleas and ticks in your turf.

Beneficial nematodes can be purchased through most garden supply stores and added to your soil to help control these pests.  Since nematodes may only attack certain insects, you need to make sure you get the right nematode to address your problem.

The Root of the Problem

nematodes - root knot

The problem nematodes that most gardeners encounter are called root-knot nematodes.  This variety of nematode feeds on plant roots and cause cancerous looking knots to form along the roots.  Above-ground symptoms of destructive nematodes include poor plant growth, lack of vigor, and wilting. 

Nematode problems are a sure sign of poor soil health.  In healthy soil, the beneficial bacteria, nematodes, and other life will keep the unwelcome nematodes in check and the soil biome in balance.  The best defense against pest nematodes is to build the soil ensuring a healthy biome. 

One Bad Apple

Nematodes have a Dr. Jeckyl and Mr. Hyde reputation.  There are millions of them in the soil beneath our feet.  Only a few cause damage to crops and garden landscapes.  These few give the rest a stained reputation.  In truth, without nematodes, it would be almost impossible to grow anything.  They are a vital part of the soil network, that mass of living organisms that inhabit our soil and make it possible for plants to grow.

As with most pests, the presence of damaging nematodes should be looked at as a symptom rather than the cause of a problem.  In most cases, the real problem is poor soil health and poor soil biome.  Building soil to encourage a proper balance of organisms in the soil is the key. 

Links and Resources

For more information about organic gardening, lifestyles, and living, visit our website at West Texas Organic Gardening.

If you found the information here helpful, you might also find these articles on our website of interest.

Organic Growing Myths

Toss Your Tiller


If you have more specific questions or problems, you can contact us using the contact form on our website. You can also post your question to our community forum at this page; West Texas Organic Gardening Community Forum.

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