Termite Control and Management

Types of termites and their classification The name "Termite" is derived from the Latin roots Tarmes and Termes, meaning wood-eating worms. Termites, given their distribution and the extent of damage, are classified as national and urban pests, and people are in no way able to control this insect individually and with temporary methods. Termites have long been one of the problematic insects for humans in green spaces, urban and rural residential complexes, and historical monuments and structures. Since this insect has high biodiversity, in the absence of correct management to control it, it will inflict much damage and harm. Termites are of two general types. One type attacks buildings and feeds on the wood present in homes, and the other type lives in equatorial regions and builds homes for itself in deserts. This group builds nests on the soil that resemble a hill, whose height sometimes reaches more than 10 meters and whose diameter reaches 3 meters, and they are very hard and solid, so that they cannot be broken even with a pickaxe. But the termites of the first group are themselves of three different types, which are subterranean termites, drywood termites, and dampwood termites. In Iran, the greatest damage to buildings and to wood in homes is caused by subterranean termites. Social castes in termite colonies In termite society, three different forms of termite can be found, each with separate duties. These three forms are called three castes, which are the soldier termite, the worker termite, and the reproductive or sexual termites. In fact, in general these three castes of the colony fall into two groups: the sexual group (including the male and female sexual individuals) and the sterile group (including the workers and soldiers). The damage caused by these insects in tropical regions to wood and cellulosic fibers used in buildings is very remarkable; they attack beams, cabinets, doors, wooden decorations, wallpaper, kitchen wooden cabinets, clothing, books, and items in storerooms, and they eat them silently and away from the eyes of us humans. Likewise, the attack of termites on industrial facilities such as wooden poles for electricity and telecommunications, military weapons depots, museums, libraries, and document-archive spaces is sometimes irreparable and is considered a national disaster. This damage goes back to the characteristic of termites in terms of their feeding method and their power to digest and absorb cellulosic materials, which in other types of insects is sometimes not seen to this extent. Controlling subterranean termites Since subterranean termites cause more damage to building facilities in cities and villages than other types, controlling this type of termite in residential spaces is one of the concerns of researchers and people in regions contaminated with termites. In general, the program for controlling this pest in urban environments includes three strategies: "Preventive measures before construction and urban planning," "Methods of control after construction," and "Quarantine measures," as follows: 1/ Preventive methods This method is the best method for preventing the attack and damage caused by the presence of termites, and it includes the following methods: 1 / 1 Examining the contaminated area and estimating the contamination: Although humans are able to build in any place, attention must be paid to the point that humans entering regions where termites naturally live means a potential risk for extensive subsequent contaminations. In other words, when termites have chosen a territory for their life, the presence of humans in such places means a great deal of trouble and difficulty in order to prevent the damage of this insect. Therefore, it is preferable not to build in such places. In practice these examinations are carried out in the field of land-use planning. 1 / 2 Cleanup: When the construction area has been examined and the severity of the initial contamination with termite colonies determined, the area must be carefully cleared of the insect's food sources. Although termites, in searching for food sources, may travel long distances underground and reach buildings, removing residual materials that can be a refuge for the insect or its nest is an effective measure that must be carried out before beginning construction. If active colonies are observed in examining the area, these colonies must be destroyed by reliable mechanical and chemical methods before construction. 1 / 3 Reducing moisture around buildings: Moisture is one of the important factors in increasing or decreasing termite populations. If buildings are located in areas where the soil has high moisture because of the presence of sewage or groundwater, one must first, through complete drainage, reduce the moisture and dry the ground. Some imagine that wetting the ground keeps termites away; although it may temporarily dampen the insect's presence, moistening the ground actually improves the insect's living conditions. 1 / 4 Using moisture-resistant materials: Most materials used in buildings have pores and gaps that cause the absorption of water and its transfer to other surfaces; in such a case, materials that are moisture-insulating must be used. 1 / 5 Insulating the water-supply and sewage networks: Among the factors that help termites penetrate buildings are defects in water pipes and sewage channels. Often these networks have leaks, and also from their connection points sufficient spaces are provided for termite entry and the creation of communication corridors. For this reason, these pipes, especially at branches and connections, must be completely insulated. 1 / 6 Creating a disinfection barrier: In some places it is necessary, in addition to insulation work, to spray the foundation and floor of the building and to disinfect their materials. In such a case, suitable pesticides must be used. 1 / 7 Protecting the wooden parts of the building: The wood used in buildings is among the most important food sources of the insect and must be kept out of the insect's reach or disinfected against it in various ways. The main methods of disinfecting wood and isolating it are as follows: Isolation with petroleum products: This method, which has long been of interest to humans and which, apart from buildings, has been used to disinfect electricity and telecommunications poles and railway sleepers, is the simple method of coating with tar. Tar-coated wood has a bad smell and is not usable in indoor spaces of buildings. An interesting point is that in some regions where the insect population density is high, in practice a group of termites attack even such wood, and after finding a way to penetrate it, they eat from the middle parts to which the petroleum material has not reached. In this case, it is as if individuals from the population, sacrificially, by eating the tar-soaked wood, open the way for the rest with their own death. Today, with the replacement of poles and sleepers with concrete ones, in practice the insect's food source has been taken away from it, and the tar-coating method has no use. Disinfection with chemicals: A number of chemicals classified into two groups, soluble in water and in organic solvents, are used to disinfect building wood. If these materials are well absorbed by the wood, they have no adverse environmental effect and are durable. Among the most effective materials soluble in water, one can mention "copper arsenate" and "chrome." Disinfection with radioactive radiation: One of the most efficient methods of disinfecting building wood, doors, and even decorations is using radioactive radiation. In this method, various types of wood are subjected to irradiation with a specified dose of gamma rays, which changes the structure of the wood's molecules so that they become very hard, and the jaws of termites will no longer have the power to chew such wood. Using wood from trees resistant to termites: Some woods, by their very nature, are less subject to damage. Such woods are naturally resistant to feeding by the insect, and this matter goes back to the type of trees, such that the wood of some trees contains repellent or anti-feedant materials against insects, including termites. Naturally, the use of the wood of these trees in construction is a deterrent factor, although the degree of this deterrence needs research. 2/ Methods of control after construction In this strategy, similar to the pre-construction strategy, the most important principle is the careful examination of the contaminated area and determining the degree of contamination. Therefore, in the first step, buildings, especially their hidden parts, must, after construction, be constantly and carefully examined. In this regard, first, by carefully inspecting the building, the degree of contamination, the intensity of the insect's destructive activity, the population density, and the manner of distribution and spread of the colony and the communication corridors must be identified, and then action must be taken for each deterrent measure. On the other hand, people generally, by carrying out insect-control measures around homes, try to eliminate this pest from their living environment, while being unaware of the aforementioned matters, without sufficient knowledge of the insect's conditions, and indifferent to the main centers of its presence, they undertake a superficial fight. For this very reason, in most cases, after one stage of spraying operations, they again witness the presence and intensification of the pest's activity. It must be noted that what we see in the home environment are worker termites, whose commander is a reproductive queen that may be a few hundred meters away in its safe underground nest, constantly producing new worker individuals, and therefore killing a few workers in one place gives us no assurance about eradicating or successfully controlling the insect. In other words, as long as the colony and the queen remain, the renewed onset of contamination is certain, so a successful insect-control program in the building and contaminated areas has two main stages: "Diagnosing the contamination (the location of the colony and queen)" and "Carrying out pest-control measures." 2/ 1 Diagnosing the contamination: For any measure aimed at successful pest control, one must first examine the location of the colony, the intensity of contamination in various parts of the building and the surrounding spaces, and the degree of the colony's presence and activity. In this case, sampling and tracing in buildings and areas are carried out randomly with special methods, and the information is recorded. The most difficult part of the work of controlling active termite colonies is the inaccessibility of the nest and the failure to determine its precise location. But by using the method of radioactive marking and tracing the marker substance in the insect's body, one can easily find the place of movement and concealment of the termites without high cost and without harm to buildings and the environment. In this method, using nuclear technology, the radioactive substance is first fed to the termite, and then, using a radioactive-radiation detection device (Tracer), the contaminated termites are detected and followed to the main nest. By determining the location of the colony, one can eliminate the colony by various methods, including chemical or mechanical. The radioactive materials used generally have gamma rays, which are harmless to humans. 2 / 2 Pest-control measures: Termite-control measures, depending on climatic conditions and the intensity of the contaminations, are carried out by the following various methods: a/ Collection and release (the TTR method): Traps can attract a considerable number of workers and soldiers. Naturally, by using these traps, whether with attractant materials or without them, one can keep part of the population away from the food sources present in the structures and capture and then destroy them. But in the collection-and-release method, a behavioral characteristic of termites (licking the body to exchange the information needed for recognizing one another) is used alongside trapping. b/ Using poisoned bait: This method became common from the early 1980s. Given that direct spraying or creating a protective barrier with pesticides around homes carries environmental risks and affects people's health, the baiting method with insect-attractant materials that cause the destruction of termites has better efficiency and does little harm to the environment. In this method, food soaked with poison is placed inside the ground and around buildings. After that, without the poisonous substance being released, worker termites are attracted to it and die from feeding on this food source. Naturally, with the death of the worker termites that have the duty of collecting food for the other members of the colony, these members too die of hunger, and in this way the termite colony is destroyed. The efficiency of this method is far greater than direct spraying and also has a lower cost. Digestive poisons are poisons that, after being eaten, cause food poisoning and consequently the death of the insect. These materials have a slow-killing property, such that termites become poisoned after 60-90 days of feeding on them and die. Poisons such as Sulfuramid and Sodium borate are used in this group. c/ Biological control method: Termites, like all living creatures, have enemies from various animal and microbial groups that cause their death. These natural enemies fall into two groups: predators and disease-causing agents. d/ Chemical method: Although this method is the only conventional method of insect control, it causes the development of resistance in the pest and the destruction of environmental resources. In this method, emphasis is placed on using poisons harmless to humans and the environment, and on the use of precise tools and methods that replace direct spraying. e/ Physical control method: This method, which has long been of interest to scientists, includes creating physical barriers in the path of the termites' nest and also using radio and sound waves to drive them away. Any object that termites cannot penetrate can be a physical deterrent. For example, in one study, sand particles were used in such a way that the jaws of the workers did not have the power to move them. Short-wavelength radio waves, because of the heat they produce, also cause the death of termites, although this method is used more against drywood termites and requires advanced equipment. Sound frequencies intolerable to insects can also cause them to flee or die. Therefore, in some cases, sound devices emitting waves within the termite's hearing range have been invented, whose frequency is not perceivable by humans but causes the insect to flee. Of course, the efficiency of this equipment and method is also very specialized and limited. 2/ Quarantine measures The basis of the spread of termites from one place to another in natural conditions is the foraging behavior of the workers and also the establishment of sexual reproductive individuals in new places after a mating flight; in the first state the spread occurs at a slow pace and within the boundaries of the main nest, but in the second state the spread is more extensive. However, in practice, extensive and sudden contaminations with termites in a new area go back to the intervention of human factors. In other words, it is we humans who, unknowingly and by our own hands, cause the extensive spread of this pest, and therefore serious attention must be paid to the quarantine, or preventing the entry, of termites into new places. Quarantine of termites can also be related to simple precautions at the level of regions, which will have a great effect on reducing the spread of this insect. These precautions are in fact recognized as an effective method of termite control or a sanitary insect-control method that prevent the spread of the insect in two areas: green and surrounding spaces of homes, and inside buildings. These measures are: a- Precautions in green and surrounding spaces Subterranean termites and drywood and dampwood termites have a close relationship with the various plants present in the green spaces of homes and parks. In other words, various types of plants can be considered a food source for these termites. Therefore, the following precautions must be observed in this regard: 1/ Not obtaining plants from areas suspected of contamination for planting in other regions. 2/ Preventing the spread of termites when planting plants. 3/ Disinfecting livestock manure and leaf mold. 4/ Caring for gardening tools. b- In buildings 1/ Not moving contaminated soil and building materials. 2/ Not using contaminated decorations and furniture. 3/ Removing unusable wood and wooden items. 4/ Removing unused clothing, books, paper, and cartons.