| Basic Termite Control
These general methods work for many termite species, but not all.
Latest and Greatest Information Fresh off the press about termites
Termites have been around for well over 250 million years. They are social insects and live in colonies, which are usually located in the ground or in wood. Most termites feed on cellulose from wood and wood by-products such as paper. Some tropical species feed on fungi and carrion. Termites are distributed worldwide with about 2500 known and described species with about 50 species being found in the United States.
Termites are divided into 3 groups based on the primary location of their colony: the subterranean, the drywood, and the dampwood termites. The biology and habits of each group are different, so an effective and detailed knowledge of each species is necessary for effective control.
The most common or economically significant members of these 3 groups can be outlined as follows.
The most common of the subterranean termites are the eastern and western subterranean and the Formosan subterranean termites; for the drywood termites, the western and southeastern drywood and the powderpost/furniture termites are the most important groups; and of the dampwood termites, there are three families. The Pacific Coast and the Florida dampwood termites cause the most problems.
In the desert southwest, the desert subterranean termites, Gnathamitermes spp., cause the phones to ring during the rainy season when they plaster tree trunks, fences, and dry litter with their soil sheetings. However, since they do not cause structural damage, any anxiety is relieved with the education of the concerned people.
RECOGNITION.
The three body regions (head, thorax, and abdomen) are broadly joined with no constrictions such as those found in ants. The antennas are moniliform, (composed of a series of beadlike segments). The tarsi are 4-segmented. Cerci are present in all forms.
Workers are creamy white with the head being slightly darker. Compound eyes or ocelli (simple eyes) are present in all forms. The workers have no wings present.
Soldiers are also creamy white, except for a dark and much-enlarged head. A large pair of mandibles is present, except for nasutiform soldiers, which lack mandibles and have head lengthened into a distinct snout. Compound eyes are absent, but some have pigmented areas. Soldiers sometimes have a fontanelle (pore like opening to the frontal gland) on trop of the head. Soldiers have no wings.
Swarmers (alates or sometimes called winged/primary reproductives) are pale yellowish to a reddish brown to black. This is dependent on the species. They have compound eyes, and a pair of ocelli (except for Zootermopsis spp.). Some are equipped with a fontanelle (porelike opening to the frontal gland) on top of the head. They have two pairs of wings of nearly equal length and width. These lie flat over its abdomen when not in use. The wings are almost clear to a smoky black in color. Wing veins are usually darker with their number and position used to identify different groups. Termite wing veins vary from species to species and are used to identify each. The wing base have a fracture line where the wings were broken off after swarming, leaving attached a small basal portion called the wing scale.
IDENTIFICATION.
It is extremely necessary to know which termite group is causing the problem because each group is quite different biologically and therefore requires different control methods. That is, one must know if the termites are drywood, dampwood, or subterranean termites. In addition, for subterraneans one must be able to distinguish the Formosan subterranean termites from the other subterranean termites because additional control measures are often required for this species.
BIOLOGY.
Termites have simple metamorphosis: egg, nymph (immature), and adult. Termite specialists separate the immature stages into larvae (young instar, workers with no wing pads), and nymphs (with wing pads). I will be using the term nymph for all immature termite instars in order to remain consistent with the PCO industry jargon. Subterranean termites have three form castes: worker, soldier and reproductive. Drywood and dampwood termites lack a true worker caste, and their functions are performed by pre-adults, which ultimately develop into soldiers or reproductives.
Workers can be separated into two basic groups: true workers who are sterile, and functional workers who are either male or female. Functional workers have the ability to molt into soldiers, swarmers, or secondary reproductives, depending on the colony’s needs. This is a tremendous termite advantage when considering situations, which can confront PCO professionals when applying control measures in the field. Workers maintain the colony, construct and repair the nest, and forage and feed the colony. Later instar nymphs also forage and help care for the young.
Soldiers are sterile and have one function They protect the colony. The enlargement of the head and mandibles is so great that they must be fed by workers. Soldiers are present within the colony in far fewer numbers than workers. Protection is often rendered by plugging a small hole in the tube or carton with its head, or if the opening is larger, by cocking its head with the mandibles open wide and waiting for or fending off invaders. It is known that nasutiform soldiers squirt a sticky, irritating liquid for defense.
Reproductives include both primary reproductives and secondary reproductives. The primary reproductives are the king and queen, which were the swarmers that started the colony. The king and queen mate periodically, and the queen may live up to 30 years. It is thought that a longer lifespan is possible.
Secondary reproductives are produced in more mature colonies. They do not, nor have they ever had wings (but may have wing buds if developed from nymph). Their body may be either lightly or darkly pigmented. Their egg production capability makes possible the most rapid increase in size in older colonies. If something happens to the primary reproductives they can serve as replacements and continue egg-laying.
New colonies can be started either by a founding pair of swarmers or by isolation of a portion of a large colony. In the Pharaoh ant species this is called budding. Termite pair formation by swarmers occurs after the swarming flight on or in the ground. Mated queens lay a few eggs the first year (sometimes as few as 20 or possibly more if 1 or 2 additional egg batches are laid. At the end of the first year, a subterranean termite colony may number up to 75 individuals whereas, drywoods may contain only up to a dozen.
New colonies can also be started by isolation or division. This will happen when a new food source is located and a sub-colony is formed to fully exploit this source. If the continual exchange of individuals with the main colony is cut off, this sub-colony can then produce the needed reproductives from either functional workers or nymphs. Remember that they can become whatever the colony needs for survival. This is probably the primary method of new colony formation in northern areas where winters are usually too severe for continuation of colonies started by swarmers.
One of the most common question made is: how many years are required before a brand new, or newly-constructed building will begin showing signs of a termite infestation. If a termite colony is started by a pair of subterranean termite swarmers at the time of construction, at least 3 or 4 years are required before even a few swarmers will be produced. Colonies are typically at least two years of age before any swarmers are thrown off. Evidence of any damage may take longer. However, if the structure is built over or close to a strong existing colony of subterranean termites, hundreds of swarmers may appear within a year. Also, in this latter situation, a tremendous or substantial amount of damage might be noticed within a year.
BASIC CONTROL.
Termite control begins with a thorough inspection of the structure and the preparation of a “to scale” graph of the structure’s foundation and/or any floors, which show either termite activity or damage whether it is active or inactive (old). The graph should include, if applicable, the following in addition to any treating specifications or instructions:
1) dimensions of the structure
2) type of foundation wall (s)
3) depth from soil grade to footer
4) location of plumbing lines and/or penetration for slabs
5) type of heating system (for slab)
6) location of cracks and/or expansion joints in the foundation or slab
7) types of floor covering on concrete slabs which require drilling (carpet, wood, linoleum, or tile)
8) type of porches present (slab/dirt-filled) location of any well or cistern if present
whether or not adequate ventilation is present (for crawl spaces)
location of excessive moisture
9) location of wood-to-ground contact
10) location of active termite infestations
11) location of old termite activity
12) location of termite damage
13) location of any possible hidden termite damage.
The gathering of this information will provide the you or the termite inspector the proper tools he will need to determine the most effective treatment necessary to combat the termites at your home.
Subterranean termite control involves either placing a pesticide barrier and/or bait using an in-ground perimeter monitoring-baiting system between the termite colony and the wood of the structure. It is essential that the treatment also includes the elimination of above-ground moisture sources which can support secondary colonies, the elimination of wood-to-ground and rigid foam board/form-to-ground contact (typically the building owner’s responsibility), reduction of crawl space humidity via vents, and/or polyethylene soil cover, and the possible injection of infested wood to rapidly kill the above-ground termites.
Formosan subterranean termites frequently require extraordinary treatment methods to insure complete elimination/eradication. Treatment often requires removal, or treatment of the above-ground cartons by injection with a termiticide like Premise 2, or total fumigation of the entire building is sometimes required. Occasionally, the Formosan termite can not be stopped even with fumigation. Seems like the withdraw into the carton which has been found to protect the termite until after a 24 hour fumigation. One of the best methods of elimination is by baiting with AG (above ground) bait assemblies. It is simply placed directly on the termite- infested wood and preferably over a shelter tube. This is to insure the termites find the bait.
The physical control of subterranean termites via selected sand particle size has recently been rediscovered. This technique takes advantage of the fact that sand particles of a certain size range are small enough that the termites cannot maneuver between them but are also too large for the termites to manipulate or remove them. The particle size range required is apparently dependent on the mandible and head capsule dimensions of the target termite species. The protective sand particle size range is 1.2-1.7 mm in diameter for the western subterranean termite, Reticulitermes Hesperus Banks, 1.7-2.8 mm in diameter for the eastern subterranean termite, Reticulitermes flavipes (Kollar), and 1.7-2.4 mm in diameter for the Formosan subterranean termite, Coptotermes formosanus Shiraki. Use of this technique is primarily for pre-construction applications, and its use is increasing in popularity, especially in Hawaii.
Drywood termite control involves fumigation of the structure or wooden object housing the infestation, or local treatment or replacement of the infested wood. Fumigation is recommended if infestations are widespread and/or difficult to access whereas, local treatment with pesticides or other means is prudent where infestations are isolated and accessible. Treatment with borate (Timbor) materials from the outside surface areas is excellent provided the wood is not painted.
Dampwood termite control involves the elimination of the moisture source and all wood-to-ground contact. Infested wood should be replaced or treated, with borate (Timbor) surface treatment or injection offering the quickest control. |
