Termites: The Hidden Menace of Your Garden and Home?

What to know about termite biology?

Termites are wood-eating insects belonging to the suborder Dictyoptera, just like cockroaches. They are grouped into eight different families found all over the world. Among these eight families, Rhinotermitidae are certainly the most invasive, with 80% living underground, making them difficult to detect. In France, only species of the genus Reticulitermes are present. There are six different subspecies, four native to Europe and two invasive species:

• The lucifugous termite (Reticulitermes lucifugus) mainly inhabits the Mediterranean coast and coastal forests
• The Corsican lucifugous termite (Reticulitermes lucifugus corsicus) is a subspecies of the lucifugous termite found in Corsica
• The heathland termite (Reticulitermes grassei) naturally lives in the forests of the Aquitaine Basin
• The Banyuls termite (Reticulitermes banyulensis) is native to Roussillon but can be found as far as Marseille
• Reticulitermes urbis, originating from the Balkans, was likely accidentally introduced. It was discovered and described in 2003 in cities in the Southwest
• The yellow-legged termite or Saintonge termite (Reticulitermes flavipes) is native to the United States but has been established in Charente-Maritime for several centuries.
  

  Lucifugous termites

In addition to these six species, we can add Kalotermes flavicolis, the drywood termite, which poses no threat to buildings.

Although slightly different from one species to another, termites are insects with chewing mouthparts that allow them to feed on wood cellulose, as well as paper or cardboard. They live in a highly organized manner in forests, where they feed on dead wood and plant debris. This is why termites play an ecological role in forest regulation: they decompose cellulose to incorporate it into the soil, structure the soil with their tunnels, improve water infiltration, while contributing to the diversity of microbial activities.

For centuries, these termites have also inhabited buildings and gardens near forests. And that’s where the problems start…

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Termites live in perfectly organized colonies with castes, similar to ants or bees. Each has its place, and everything seems predestined, as the eggs laid have a particular ontogenic potential. Termite colonies in France are lucifugous (light-averse): they never appear in daylight and live underground, in galleries. The colony is organized around a queen who lays eggs and a king who provides sperm. The rest of the colony consists of thousands of individuals with specific roles:

• Workers: they make up about 80% of the colony. These are sterile termites, with elongated soft bodies, whitish in colour. They have round heads, short and fine antennae, but no wings or eyes. They are responsible for construction and maintenance tasks within the colony, feeding the young and other individuals.
• Soldiers: they represent 2% of the colony. They are distinguished by their brown heads with sharp mandibles. They are tasked with defending the colony.
• The nymphal line: nymphs undergo several moults to reach the adult stage, known as imagos. Some winged imagos will establish new colonies through swarming in spring, from April to June, while others are secondary reproductors or future workers who can take over in case of the queen’s or king’s death. These secondary nymphs also play a role in colony dispersal due to accidents, such as during demolition work. They may also leave the mother colony to reproduce themselves.
  

  Termites are highly prevalent in the southwest, Corsica, and the Paris region (source: https://www.ecologie.gouv.fr/)

How to detect the presence of termites and what to do?

To live happily and form a beautiful colony, termites need three essential elements: darkness, warmth, and humidity. And of course, cellulose to ensure the sustenance of all members of the community. That’s why they can easily settle in the garden soil, near a moist spot like a pool, a well, a pond, a water point like a tap, a pond… with wood nearby. And they will be very difficult to detect, as they are completely invisible. Indeed, unlike woodworms, they do not produce visible sawdust. The only clue that can put you on the trail of termites is the “mud tubes” that worker termites leave behind. These tubes, most often vertical, made of saliva, wood residues, excrement, and soil, are actually external galleries to the colony that allow termites to invade a tree or a facade, while being hidden from light.

If you have a large plot of land or a wooded area, do not hesitate to inspect trunks or large branches, dead or very damaged. By probing with a pointed tool, check that your wood is not hollowed out with galleries lined with termite cement, composed of saliva, excrement, and soil. The wood gives the impression of a millefeuille. Some termites can even attack living trees, through their root system, especially in cities like Paris. They have a preference for softwood species, such as lime. Although they also attack other trees like plane trees or ash trees.

In spring, it is also possible to see the winged adults seeking to mate to establish a new colony. But these adult termites strongly resemble flying ants or mayflies.

What damage can termites cause?

As long as termites remain in the undergrowth, the damage is very limited. However, as soon as they settle near buildings, the danger becomes more significant. Indeed, termites can infest anything made of wood in a house: frames and joinery, structure, stairs, parquet flooring, floors and skirting boards, furniture… They also appreciate places where paper is abundant, such as archive services or libraries. Without anything being visible, as termites, who fear light, refrain from digging into external walls. They also move within plaster partitions.

Generally, they have a preference for buildings where humidity and warmth prevail. Coming from the ground, termites attack buildings from the bottom up, thanks to the famous runners.

By digging galleries and feeding on cellulose, termites considerably weaken wooden furniture or structures. Consequently, there are significant risks of collapse, making your home potentially dangerous, even uninhabitable in the event of extensive infestation.

Wood infested by termites, with a flaky appearance

If there is a suspicion of a termite presence, it is essential to consult a professional who will confirm their presence or absence, using, among other methods, acoustic solutions. Subsequently, they can implement a curative treatment, combined with a preventive treatment.

Finally, according to Law No. 99-471 of June 8, 1999, any occupant or owner of a building attacked by termites is obliged to report it to the town hall. Failure to comply with this obligation may lead to sanctions.

How to prevent them from settling in?

Several preventive measures can be implemented to avoid infestation, especially in departments infested by termites:

• Plant wood stakes in your garden and regularly check them for potential attacks
• Soak the roots of imported trees
• Remove dead trees in the garden
• Fix all water leaks in irrigation systems
• Indoors and outdoors, treat all points of moisture, such as infiltrations or water leaks, or rising damp in walls through capillarity
• Elevate firewood to insulate it from the ground using materials other than wood. There should be no contact between the wood and the ground
• Avoid storing firewood, planks, pallets, or debris containing cellulose (paper, cardboard, old furniture…) along a house facade or in a cellar with a beaten earth floor.

  House infested by termites