Detecting the presence of a pest usually means finding the animal itself or some evidence of its activity: trap captures, droppings, damage, tracks, images or reports from people. But a technology originating in the field of biodiversity research is beginning to offer another possibility: looking for the genetic traces that animals leave behind in the environment.
This is known as environmental DNA, or eDNA. Animals and insects continuously release small amounts of biological material through scales, hair, droppings, secretions, cellular debris and other materials. Some of this DNA can remain temporarily in water, soil, sediment or even suspended in the air and, using molecular techniques, can be used to identify which species have been present in a particular environment.
The technology has been used for years in ecological research, particularly in aquatic environments. Now, new studies are exploring applications much closer to urban pest management, from detecting mosquitoes through air samples to searching for traces of rodents in urban stormwater runoff.
Are we facing a new, future scenario for pest detection in our sector?
We are still a long way from replacing traps or professional inspections, but the concept opens up a particularly interesting possibility: detecting species that are difficult to observe without having to capture them directly.
What Exactly Is Environmental DNA?
Environmental DNA is genetic material obtained directly from an environmental sample, without first having to capture or handle the organism we are trying to locate.
Instead of looking for the animal, we look for what it has left behind.
For example, a sample may come from:
- water,
- soil,
- sediment,
- material accumulated through runoff,
- or even air.
The laboratory then extracts the DNA present in the sample and uses techniques such as PCR to search for genetic sequences characteristic of a particular species.
This capability is particularly interesting when dealing with small populations, species that are difficult to observe or environments where visual inspection has limitations. Various scientific studies highlight the sensitivity and non-invasive nature of eDNA as some of its main advantages for detecting species and studying their distribution.
In an urban environment, this principle could eventually be applied to a very specific question: could we know that a pest is present before we actually see or capture it?
Detecting Mosquitoes from the Air
One of the most interesting advances emerged in February 2026.
Researchers affiliated with the Senckenberg Research Institute and other German institutions published a proof-of-concept study on the use of airborne environmental DNA to detect the Asian tiger mosquito, Aedes albopictus, in Conservation Genetics Resources.
The approach is particularly innovative because much of the previous work involving mosquito environmental DNA had focused on water samples.
In this case, the researchers used filters to collect airborne particles from climate-controlled chambers containing Aedes albopictus. They then analysed the samples using specific PCR techniques and successfully identified mosquito DNA.
The experiment demonstrates something important: mosquitoes can leave enough genetic material in the air for it to be detected using molecular techniques.
However, there is a fundamental limitation. The researchers themselves point out that the study was conducted under controlled conditions and that larger-scale field experiments are needed to determine how reliably the method works in real-world situations.
A controlled room containing known mosquitoes does not present the same complexity as a park, sewer network, warehouse or open urban facility, where wind, humidity, distance and numerous different sources of DNA can affect samples.
So, we are not yet talking about placing a filter in any facility and automatically obtaining an accurate map of mosquito activity. But the principle has already been shown to work.
From Looking for Captures to Looking for Signals
If the technique can be successfully transferred to field conditions, it could complement some traditional surveillance systems.
Today, detecting mosquitoes usually involves combining methods such as adult mosquito traps, ovitraps, breeding-site inspections and checks of potential breeding areas.
eDNA introduces a different approach.
Imagine a facility where there is suspected activity from a particular species, but the traps have not yet produced any captures. A system capable of collecting and analysing genetic material could add another signal to the investigation.
This would not necessarily mean that environmental DNA could always detect a pest earlier than a trap. The amount of DNA, its persistence, environmental conditions and even sample contamination can all affect the result.
Its potential would instead lie in adding another layer of information to surveillance.
Instead of relying exclusively on a single form of evidence:
capture → identification → intervention
we could move towards systems that combine:
traps + inspections + sensors + environmental information + genetic evidence.
Technical decisions would still depend on correctly interpreting all of these signals.
What If We Could Track Rodents Through Rainwater?
Mosquitoes are not the only potential application being investigated.
In 2025, researchers from the University of Tokyo published a study on the use of solids found in urban stormwater runoff to detect rodent environmental DNA.
The idea is based on a relatively simple principle.
When rain falls on a city, the water carries dust, organic matter, hair, faecal material and numerous other substances accumulated on urban surfaces. Among them may be genetic material from animals that use those spaces.
The researchers developed a passive sampling system designed to capture solids transported by this runoff and then analysed the material using molecular techniques.
The study detected mouse DNA in several samples, although the detections were below the established limit required for accurate quantification. The researchers also developed specific assays targeting mice and rats, noting that further improvements in quantification and system validation are still required.
For this reason, the findings should not be interpreted as a new commercial method for counting rats in a city.
What is interesting is the concept itself: urban infrastructure could become an indirect source of information about animals that normally remain hidden.
A New Tool for Discovering What Is Happening Beneath the City
In urban rodent management, one of the biggest challenges is determining precisely where activity is concentrated.
Reports from the public, captures and inspections provide essential information, but none of these methods alone offers a complete picture of the population.
Rodents move through sewers, vacant plots, buildings and other difficult-to-access spaces. They can often remain active without being directly observed.
In the future, collecting DNA at strategic drainage points could help answer questions such as:
- In which areas does genetic material from a particular species repeatedly appear?
- Do these signals vary between neighbourhoods?
- Do they decrease following an intervention?
- Do traces appear in areas where no reports or captures have yet been recorded?
For now, these remain hypotheses and areas of research rather than fully established operational capabilities. The Tokyo study highlights challenges such as the presence of substances that can interfere with PCR and the need to improve the quantification of target DNA.
Nevertheless, the possibility of turning stormwater runoff into a kind of “aggregated sample” of what is happening across an urban area is particularly interesting for large-scale surveillance programmes.
Can eDNA Replace Traps?
For now, no.
And the true value of this technology will probably not lie in replacing them.
A genetic test can indicate that DNA from a particular species is present, but pest management professionals need much more information before deciding what action to take.
A positive detection does not automatically reveal how many individuals are present, where the source is located or whether the activity is still ongoing at that moment. DNA can also degrade, be transported from another location or occur at concentrations too low to be detected.
This is why the most interesting scenario is multi-method surveillance.
Traps make it possible to observe activity and capture specimens. IoT sensors and smart traps connected to management systems can generate continuous data and alerts. Inspections help professionals interpret structural and environmental conditions. Smart cameras are beginning to identify and count certain pests using artificial intelligence and computer vision. And eDNA could add molecular evidence of species that have passed through a particular environment.
Each tool would answer a different question.
From Reactive Pest Control to Increasingly Preventive Surveillance
Interest in environmental DNA also fits within a broader transformation taking place in urban pest management.
The sector is moving away from models based primarily on reacting to an incident towards systems designed to detect weak signals before the problem becomes obvious.
Smart traps, remote monitoring, heat maps for pest management, computer vision and data analysis are already reinforcing this trend. eDNA could become another component within this ecosystem.
In a future scenario, an environmental health company could combine information from multiple sources:
a trap records activity, a sensor detects changes, an environmental sample identifies genetic material, and the site’s historical data shows that the same area has experienced incidents before.
The real value would come from connecting all these signals to determine where to inspect, what priority to assign and when to intervene.
This shift towards connected, data-driven management is already part of the sector’s technological transformation. Specialist platforms such as iGEO for pest management companies make it possible to centralise information from services, control points, smart devices and other sources, improving traceability and supporting better decision-making.
eDNA technology still needs to overcome significant challenges before reaching this stage: standardisation of sampling, laboratory costs, analysis times, contamination risks, interpretation of results and, above all, validation under real-world urban conditions.
However, experiments involving mosquitoes and urban stormwater runoff show that an idea which only a few years ago seemed confined to ecological research is beginning to move closer to very practical challenges in environmental health and pest management.
Conclusion: The Next Sign of a Pest Could Be Invisible
For decades, pest surveillance has largely depended on what we can observe: animals, captures, damage or other visible signs.
Environmental DNA introduces a different possibility: detecting what we cannot see through the biological traces it leaves behind.
Experiments involving Aedes albopictus show that even the air can contain enough genetic information to identify a species under controlled conditions. Research into urban stormwater runoff, meanwhile, demonstrates that material carried by rainwater can contain useful traces for studying animals hidden within cities.
It is still too early to describe this as an everyday tool for pest management companies. However, its potential is significant.
The future of urban pest surveillance will probably not depend on a single technology, but rather on combining professional inspection, traps, sensors, images, data and new forms of biological evidence.
And perhaps, in a few years, finding a pest will not begin with seeing it.
It may simply begin with finding the DNA it left behind.
