Technical News
The Not-So-Invisible Enemy: Nematodes Destroy Yields Around the World
by Bernardo Borges, PhD – FertiGlobal Technical Manager Brazil
On a hot summer afternoon in Brazil, a farmer looks at his yield map and sees the same picture as always: red patches that grow a little larger each year, where the harvester slows down and yields stubbornly stay lower. The soil has been corrected and fertilized, weeds, pests and diseases are under control, and the nutritional program was carefully designed. Everything went according to plan. “It must be the weather,” he thinks. Maybe the soil is “tired.” What he usually does not realize is that, just a few centimeters below his boots, a different story is unfolding.
In the root zone, hundreds of thousands of plant parasites are quietly stealing his yield long before the crop reaches the trucks. Nematodes silently feed, weaken roots and destroy productivity, but they are often ignored simply because we rarely see them. Their impact on agriculture, however, is anything but small.
Across all continents and production systems, nematodes act like a hidden toll on plant roots. A meta-analysis conducted by the American Phytopathological Society, grouping crops such as soybean, maize, wheat, rice, potato and sugar crops, showed that approximately 14% of potential yield is lost even before harvest — amounting to around US$125 billion in direct losses every year. Similar scenarios are reported in tobacco, banana and other high-value crops. In those fields, nematodes are not just “one more factor”: they are often the difference between profit and loss.

Part of the reason these parasites are ignored lies in how their damage appears in the field. Nematodes do not leave bite marks, they do not show up as clouds above the canopy, and they do not cover leaves with mycelium. They puncture roots, induce galls, create lesions and compromise water and nutrient uptake. Aboveground, many symptoms resemble nitrogen deficiency, water stress, poor seed quality or soil compaction. Without a clear understanding of what is really happening, these signs are often underestimated and attributed to other causes. It is no coincidence that it is still common to hear farmers say, “I don’t have nematodes in my fields.” Not having them is one thing; not knowing they are there is something quite different.
Brazil offers a clear example of how serious this “hidden” problem can become. A recent study conducted by the Brazilian Nematology Society, in partnership with private institutions, analyzed soil and root samples from across the country and detected nematodes in more than 90% of the samples evaluated. As mentioned before, not so invisible after all. This pressure costs Brazilian agriculture several tens of billions of dollars every year. In soybean — the country’s flagship crop — when the effect of nematodes is considered over time and across different regions, the conclusion is simple and uncomfortable: one out of every ten harvests is lost to them. A similar story is seen in crops such as coffee, sugarcane and citrus, where these organisms do not only reduce yield, but also shorten the lifespan of perennial plantations.
Why, then, despite this scale of damage, does the problem still sometimes seem secondary in agriculture? One reason is psychological: we tend to focus on what we can see. Another lies in the way nematodes erode productivity—gradually, in a cumulative and silent way. A few percentage points less yield this year, a bit more next year, a coffee field replanted earlier than planned, a sugarcane field with a sharp drop in production. No single event feels dramatic enough to demand an immediate reaction, but the long-term effect on productivity and profitability is substantial. The good news is that this enemy is not invincible.

Turning nematodes from a chronic, silent loss into a manageable risk starts with a simple step: making them visible in our decision-making. In recent years, routine soil and root sampling has been shifting the mindset from “I don’t have nematodes in my fields” to “what can I do to control this pest?”. Biological solutions and advances in soil health strategies have added new layers of protection within an integrated management approach. Beneficial microorganisms that parasitize or antagonize nematodes, improvements in soil structure and organic matter levels, and the use of antagonistic crops or species that exude toxic compounds to these parasites — breaking away from conventional rotation — have all been added to this toolbox. Seeing, measuring and integrating these tools turns nematodes from a hidden villain into a manageable risk within the strategy for productivity and system longevity.
Ultimately, recognizing nematodes as part of the production equation is deciding that we will no longer silently give up one harvest in every ten. As we incorporate diagnostics, integrated management, biological innovation and plant bioactivation strategies into our routine, we move from merely reacting to red patches on the yield map to building more resilient, profitable and sustainable systems. The enemy beneath our feet remains microscopic, but once it is seen, measured and managed it loses the power to decide the future of the crop – it becomes just another variable under our control.






But intensive farming has taken its inevitable toll – growers report depleted soils, and it’s recognised as an area on the ‘front line’ of climate change: altered rainfall patterns have increased the need for irrigation, leading to worries about groundwater depletion and desertification.
































