What are Nematodes?

Photo Credit: Angela Tenney

Nematodes are very small, slender roundworms in the phylum Nematoda, and are often classified by feeding (trophic) groups such as herbivores, bacterivores, fungivores, predators, omnivores, and unknown/free-living. Nematodes contribute to soil quality by mineralizing soil nutrients to plant-available forms, controlling the populations of other soil organisms, suppressing disease-causing organisms, dispersing microorganisms, and serving as a food source for other organisms.

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Regional Educator ResourcesTechnical Resources
Title Source Resource type and Date Short Summary / Preview
Purdue Soil Health Education website Purdue Soil Health Education website Video

Sep 2017

Dr. John Graveel, Purdue Agronomy Department discusses microbiology activity within soils.

Nematodes Purdue University Extension Fact Sheet

May 2010


An Extension publication on nematodes written by Jamal Faghihi and Virginia Ferris.

The Living Soil: Nematodes USDA-NRCS NRCS Webpage

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An incredible variety of nematodes function at several trophic levels of the soil food web. Some feed on the plants and algae (first trophic level); others are grazers that feed on bacteria and fungi (second trophic level); and some feed on other nematodes (higher trophic levels).

Nematodes as Indicators of Soil Health University of Wisconsin Extension Webpage



The search for easy-to-study organisms with activities and abundance reflective of microbial communities led ecologists to nematodes, a most diverse and successful phylum only one step above microbes in the soil food chain and represented in every soil on earth.

Are soil nematodes beneficial or harmful? Michigan State University Extension Webpage

Dec 2013


The majority of soil nematodes are beneficial to soil health and the environment.

Nematodes and cover crops Michigan State University University Webpage

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Selecting cover crops for sites infested with plant-parasitic nematodes in Michigan

Soybean Cyst Nematode Purdue University Extension Webpage

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Soybean cyst nematode (SCN) is a severe problem in Indiana, partly because of the state’s intensive soybean culture. This nematode is capable of making marked yield losses (up to 50%) and has been reported in at least 89 Indiana counties (Figure 1). We estimate that about 45% of fields in Indiana might be infested with SCN.

PLFA video protocol JoVE from University of Wisconsin-Madison Researchers Video



This video protocol explains how phospholipid fatty acid analysis is done and how to interpret the data.

Title Source Resource type and Date Short Summary
Role of Nematodes in Soil Health and Their Use as Indicators The Journal of Nematology Peer-Reviewed Publication

Dec 2001


The composition of nematode communities (plant-parasitic and free-living) may be used as bioindicators of soil health or condition because composition correlates well with nitrogen cycling and decomposition, two critical ecological processes in soil. Improving existing indices or developing alternative indices refined by a greater understanding of the biology of key taxa may enhance the utility of nematodes as bioindicators.

Nematodology Purdue University Extension Webpage

Not Dated


Describes the work of the nematode lab at Purdue, now closed and no longer accepting samples.

Test for Nematodes at Harvest Brownfield News Article with Radio Excerpt

Jul 2019


Take nematode samples after mid-July, close to harvest to determine if the pest is in fields. The best time to soil sample is at harvest time, you will have the highest numbers. The best modes of control currently include crop rotation, cover crops, and using resistant varieties.

This page reviewed by Liz Schultheis and John Wilson.

Last reviewed 10/25/19