Beneath every field is a busy underground world. Plant roots share space with bacteria, fungi, and microscopic animals that all influence how well crops grow. Among the most important of these tiny creatures are nematodes — worm-like organisms that can either work for you or against you, depending on who’s in charge.
What Are Nematodes?
Nematodes are long, cylindrical, worm-like animals found on all seven continents — even Antarctica. They live in freshwater, lakes, rivers, oceans, soils, and on plant roots. Most nematodes are a crucial part of the soil food web and play a vital role in nutrient cycling and organic matter breakdown.
Some nematodes are beneficial, some are harmful, and some are neutral. Knowing the difference — and how to tip the balance toward the good guys — is key to building resilient, productive soils.
The Good: Free-Living Nematodes (FLNs)
The nematodes that help transform carbon, move nutrients, control pests and diseases, and break down organic matter are called Free-Living Nematodes (FLNs). Based on what they eat, FLNs can be bacteria feeders, fungus feeders, predators (hunters), or omnivores that eat a mix of bacteria, fungi, and other nematodes.
These are the “good guys” of your soil system. A soil rich in FLNs signals a complex, active food web with robust biology working in your favor.
The Bad: Plant-Parasitic Nematodes (PPNs)
On the other side are the troublemakers: Plant-Parasitic Nematodes (PPNs). These nematodes feed on plant roots and leave them weak and vulnerable to infection by other disease-causing organisms in the soil.
Globally, PPNs cause an estimated $173 billion in crop damage each year across crops such as potatoes, carrots, soybeans, rice, tomatoes, and wheat. They use a straw-like mouthpart to inject chemicals into root cells, breaking them down into a “plant-cell soup” that they then consume.
Some of the most damaging PPNs include root-knot nematodes, cyst nematodes, and root-lesion nematodes.
The Beauty: Nature’s Built-In Defense System
Here’s the good news: while plant-parasitic nematodes are a threat, a healthy and biologically active soil can naturally hold them in check. This is where the beauty of biology really shines.
Free-living nematodes are beneficial and desirable, while plant-parasitic nematodes are harmful and unwanted. When FLN populations are strong, they can help naturally control and reduce PPN numbers. Their presence and effectiveness depend on the health and vitality of the soil’s biological ecosystem.
Why does this matter? Because FLNs feed on soil bacteria and fungi. If you have a vibrant microbial community, you’re essentially feeding your FLNs — and in turn, they help keep harmful nematodes in check.
Fungi That Attack Nematodes
Certain fungi act as powerful biocontrol agents against PPNs. Species such as Trichoderma and Aspergillus can directly attack and parasitize plant-parasitic nematodes and their eggs.
Trichoderma can physically attack plant-parasitic nematodes, using sticky webs or tightening rings to trap and immobilize them, and it can also envelop and destroy nematode eggs. In addition, fungi like Trichoderma and Aspergillus stimulate the production of plant defense enzymes (such as peroxidases and chitinases) that reinforce cell walls and make it harder for nematodes to penetrate and establish feeding sites.
Endoparasitic Bacteria Inside Nematodes
Some beneficial bacteria take a different approach: they live inside nematodes as endoparasites. These bacteria can form endospores inside plant-parasitic nematodes and eventually kill them from within.
Rhizobacteria as Nematode Bodyguards
In the rhizosphere, bacteria such as Bacillus and Pseudomonas species produce antibiotics, volatile organic compounds (VOCs), and hydrogen cyanide that can suppress PPNs. Some of these compounds attract nematodes, and once ingested, they act as toxins. These bacteria may also adhere to nematode surfaces, forming spore-like structures that cause physical damage and lead to nematode death.
The Beauty of LiquiLife (LL) and LiquiLife+ (LL+)
This is where BioActive’s products step into the picture. The beauty of LiquiLife (LL) and LiquiLife+ (LL+) lies in their broad-spectrum nature. They are enriched with a diverse mix of beneficial bacterial and fungal species that contribute to effective biological control of plant-parasitic nematodes while feeding the beneficial free-living ones.
More than 4,000 species of bacteria and fungi can serve as food sources for FLNs, helping boost their populations and indirectly suppress PPNs. On top of that, key genera such as Bacillus, Pseudomonas, Trichoderma, and Aspergillus play an even more active role by directly attacking or parasitizing PPNs and providing direct biological control.
Final Thoughts
Nematodes don’t have to be a mystery or a constant threat. When growers understand the balance between the good and the bad — and invest in building a diverse, biologically active soil — they tap into nature’s own defense system.
Whether you’re battling nematode pressure today or building long-term soil resilience, BioActive’s LiquiLife and LiquiLife+ help stack the deck in favor of the good guys: healthier roots, balanced biology, and stronger crops season after season.