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A technician in a store room shines a UV torch onto tracking gel, highlighting the footprints of a mouse

Shining a new light on rodent infestations

Harry Wood

Rentokil has developed a new, unique tool to help assess the extent of rodent infestations. The Fluorescent Tracking Gel is a specially formulated non-toxic fluorescent gel that highlights rodent tracks on virtually any vertical or horizontal surface.

When a rat or mouse infests a kitchen, restaurant, food store or food processing factory, one of the first tasks is to find out where they are and the routes they take to get to food and shelter. The larger the building, the harder it is to locate the rodents and their hiding places.

The Fluorescent Tracking Gel is making this task much easier and Rentokil technicians are already receiving positive results in field trials on customer premises. Rodents are intelligent, agile and small, they easily into places humans find difficult to access or may not think to look. They can climb cables, wires, pipes, conduits, squeeze through gaps and gnaw holes through many types of material to gain access to buildings and hidden spaces.

The Fluorescent Tracking Gel has been deployed on customer premises worldwide with outstanding results, helping to solve infestation problems that previous conventional control measures could not solve. This new innovation has quickly become a key component in identifying root causes of infestations and adds a smarter tool to the resources of our pest control technicians.

rodent tracking gel

Why are rodent surveys important?

The first step in getting rid of rodents is to survey the infested property to find out where they are and how many there are. Even today, many pest controllers simply lay down bait or traps, without an understanding of the best places to position them on the site. A low-cost service without a proper survey can result in an ongoing problem for businesses when rodents return and cause recurring infestations. The customer often ends up with larger infestations and much higher pest control bills due to the delay in addressing root causes.

There are several factors that make a thorough rodent survey by a trained pest control professional essential:

1. Rodent agility

rodent image

Rats and mice are highly agile and enter buildings in many ways, so you need to inspect all the vulnerable places that they can access. Rodents can:

  • Run along or climb electrical wires, pipes, fences, poles, ropes, cables, vines, shrubs, and trees
  • Climb almost any rough vertical surface, such as brick, stone, wood, concrete, weathered sheet metal, and many plastic products
  • Crawl along or through pipes and conduit
  • Crawl along underground utility and communications lines
  • Gnaw through many types of materials, including wood, low-quality concrete, concrete block, rubber, vinyl, fibreglass, plastic, lead, aluminum sheeting, window screens
  • Research conducted at our Global R&D Centre in the UK, Mice can squeeze through gaps such as under a door only ¼  inch/6mm wide and small rats ½ inch/ 12 mm
  • Mice can jump up to 12 inches (30 cm) horizontally and 18 inches (46 cm) from a floor to an elevated surface

2. Rodent senses

rodent image

Rats and mice have well-developed senses of smell, taste, hearing and touch. The sensitivity of their whiskers enables them to move around at night confidently in complete darkness using these senses. This is why it is rare to see them during the daytime. They have poor eyesight which means they cannot see detail but can detect shape and movement in dim light.

3. Structural weak points in commercial buildings

rodents in buildings

Commercial buildings such as offices, warehouses, hotels, supermarkets and food processing plants have numerous potential weak points that can be exploited by rodents.

Each part of a building has different risks for entry, harbourage and providing access to other parts of the building. Poor building design and maintenance give rats and mice opportunities to enter buildings and get around them in numerous ways. Their intelligence, curiosity and agility mean that if there is a weak point they are likely to find it.

Weak points in the structure of buildings that allow rodents entry include:

  • Doors: Badly fitted and damaged doors and frames can provide entry points for rodents. Gaps under doors, including sliding doors, can be protected with metal bristle strips. Research conducted at Rentokil’s Global Research and Development Centre, the Power Centre, showed that mice can gnaw through nylon bristle strips in eight days. Wooden doors can be protected by metal panels to prevent gnawing. Doors in busy facilities can be left open for long periods to allow easy entry and exit of people and machinery for operational reasons, also allowing rodents to get inside.
  • Windows: Badly fitted and damaged or decayed window frames can provide holes for entry and enlargement. Open windows can be an easy way to get into a building if the structure or features such as cables and pipework allow them to access the window.
  • Vents: Roof and wall vents for central heating, clothes dryers, air extraction vents, sewer vents etc. installed without strong, well-attached screening.
  • Flooring: Foundations and concrete slabs can have gaps and cracks large enough for rats and mice. In older homes, underfloor ventilation can give access to the building, and cavities under floors allow access and movement of rodents around a building. Gaps in flooring material, from badly fitting boards and planks, or holes made for pipe and wiring access, allow rodent to get in and out of the space. Underfloor cableways can act as highways for rats and mice.
  • Walls: Cracks and holes in the material used in walls: brickwork, breeze blocks, concrete and metal panels.
  • Attic/ roof space: Rats and mice can get into attics and roof spaces via the roof, vents, cables, pipework and even the walls, both internally and externally, depending on their construction. Once inside, they can easily travel over rafters or ceiling panels and get to adjoining roof spaces, such as in terraced housing, through gaps under the roof beams.
  • Basement: Casements and cellars can have multiple entry points, as listed above, and provide harbourage and entry routes to the rest of the building via pipework, cable ducting, shafts. In addition, condensation on pipes and a damp environment can provide moisture to rats, mice, and other pests.
  • Pipes: Water, gas, heating system, air conditioning and drain pipes where they pass through a wall, floor or roof can have gaps that rodents can squeeze through.
  • Cables: Rats and mice are agile enough to run along communication and electrical cables suspended in the air or attached to walls.

What are the signs of rodents in my business?

A survey to assess a rodent infestation involves a systematic inspection of the building and surrounds to look for the signs of rodents:

– Droppings: Mice and rats produce large numbers of droppings: mice about 80 droppings per day and brown rats about 40
– Dirty smear marks along their runs made by their oily fur
– Gnawing damage around holes, cables, packaging, or on food products
– Rodent runs – routes commonly used to travel around a property
– Nests and harbourage – any undisturbed space or corner in a building can be used, such as roof voids, underfloor spaces, ducting, cavity walls, inside stacks of foodstuffs
– Live or dead rodents
– Smell — mice urinate frequently which creates an ammonia-like smell
– Noises of rodents scampering, gnawing, scratching and squeaking in hidden places

Tracking rodents

Finding out where the rats and mice are located and where they are active in an infested building is one of the essential tasks in planning control measures. For decades pest controllers have used a simple powdery substance, generically called tracking dust, to show where rats and mice are running around.

Tracking dust consists of talcum powder, flour or china clay, but more recently a range of branded products, some with fluorescent dyes, have entered the market. These should not be confused with toxic tracking dusts that are designed to kill rats and mice after they swallow the dust when they groom themselves.

Tracking dust is simply scattered on a floor or flat surface where rats or mice are suspected to run and left overnight to see if tracks appear. Tracking dust has limitations, however. It can be difficult to spread and clean up and should not be used where the dust can drift and contaminate food. Also, it can only be used on smooth horizontal surfaces.

As described earlier, rats and mice are agile creatures and don’t stick to smooth flat surfaces to find food and shelter in buildings! Considering all the structural weak points in buildings listed above, it can only be used in a limited number of risk areas. This is where Rentokil’s new Fluorescent Tracking Gel leads the way in highlighting rodent activity.

What is Fluorescent Tracking Gel?

Rentokil fluorescent tracking gel for highlighting rodent tracks

Rentokil’s innovative Fluorescent Tracking Gel is a specially formulated non-toxic fluorescent gel that can be applied to virtually any surface where rats and mice can run or climb.  The gel is painted onto a surface using the applicator in an area where there is evidence of or suspected rodent activity. The gel does not dry out and when the rodents run over it or climb on a surface where it has been applied, it sticks to the feet, belly, and tail.

The rat or mouse then leaves a trail of the gel wherever it goes. The fluorescent dye in the gel lights up when a UV torch is shone on it by a Rentokil technician, highlighting rodent trails in a building. This gives a good indication of where to put traps or bait and helps to determine control measures to take and advice for customers to prevent further infestation.

The gel’s properties make it far more versatile than tracking dust. The built-in brush in the applicator makes it easy to apply gel in a controlled and precise way on surfaces such as shelving, beams, around holes and restricted places where rodent activity is suspected. The gel is easy to remove with a wet cloth or sponge, or scraping tool, when no longer required.

Certified as safe in food handling areas

Mouse footprints under a kitchen counter

The gel has been certified as food safe by HACCP International. This confirms that Fluorescent Tracking Gel can support the integrity and safety of food and complies with food safety legislation and standards endorsed by the Global Food Safety Initiative.

The gel can safely be used in splash and spill zones in areas where food is handled in businesses, such as in kitchens and food processing areas.

pest control innovation to support commercial rodent control

Harry Wood
Harry Wood

I am a Content Communications Editor at Rentokil Initial, writing content for all our marketing activities on topics as diverse as pest control, pest-borne diseases, food safety, climate change, wellbeing, hygiene and airborne diseases. I've been an editor and writer for over 30 years in academic and business roles. I started life in the Forestry Commission, moved into tropical forestry and environment in Thailand before migrating to the world of healthcare IT and medical technology back in the UK. My role at Rentokil Initial has given me the chance to return to some of my roots when writing about wood-boring insect pests ... or is that boring Wood writing about insect pests?


  1. The fluorescent tracking method is genius! I don’t believe I’ve seen this used before. How simple and effective. Thank you for sharing!

  2. It’s actually a nice and useful piece of information.
    Thank you for sharing.

  3. This tracking gel approach is not available in the USA….. as it is not approved for use here. Rentokil is a UK based company.

  4. Please send me information on ur product . Is it available to retailers or consumers?

  5. Hi
    My brother is a technician in the UK and recommends this product – can I buy it in New Zealand?

  6. It’s nearly impossible to find well-informed people on this topic, however, you seem like you know what
    you’re talking about! Thanks

  7. I’ve been thinking of ways on how to eliminate the mice from my house, but so far I’ve failed, therefore, I’m considering hiring a mice removal service. I never knew that rodents can crawl through pipes and conduits. It’s also interesting to learn that their whiskers are so sensitive which enables them to move around at night.

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