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Typical signs of termite infestations include swarming of winged adults in the spring and occasionally autumn. A "swarm" is a group of adults that leave their nest to establish a new colony. Swarming occurs when a colony reaches a certain size. Emergence is stimulated when temperature and moisture conditions are favorable, usually on warm days following rainfall. Other signs of termite presence include "pencil-size" mud tubes constructed over the surface of foundation walls, mud protruding from cracks between boards and beams, and hollow sounds from infested wood when it is tapped, or extreme softness when probed with a knife. Termites feed slowly and there is no need to panic. Description: Subterranean termites are social insects that live in nests or colonies in the soil. Each colony consists of three forms or castes of individuals, which are the reproductives, workers, and soldiers. Reproductives can be winged (primary) or wingless (secondary). The latter are found in mature colonies and serve as replacements if something happens to the primary reproductives. Winged, primary reproductives (alates) are coal black to pale yellow-brown, flattened and about 6 to 9 mm (1/4 to 3/8 inch ) long, with pale or smoke-gray to brown wings. Secondary reproductives are white to cream-colored with short wing buds. Workers are wingless, white to grayish-white with a round, yellow-brown head and about 6 to 9 mm (1/4 to 3/8 inch) long. Soldiers are also wingless and resemble workers except that they have large, rectangular, yellowish and brown heads with large mandibles (jaws). Swarmers have straight, bead-like antennae, a thick waist and a pair of long, equal-length wings that break off easily. The presence of winged termites or shedded wings inside a home are signs of a termite infestation.
Life Cycle: In a typical termite colony, the king and queen are the only active reproductives; they perform no other function. They are fed by the other termites, and some have lived up to 25 years. A mature queen can lay thousands of eggs each year. During the two-week incubation period, eggs are tended by the worker termites. The nymph hatches directly from the egg. Attendants feed nymphs regurgitated food for the first two weeks, enabling them through molting to become workers, soldiers, reproductives or supplementary reproductives. As the reproductive nymph matures, its body lengthens and sexual organs develop. The body turns black, eyes become functional, and wings extend twice its body length. The worker nymph has no eyes and is sterile. Its main function is to provide the colony with food, usually obtained by eating the wood of buildings. The soldier nymph develops a long, armored head and large jaws during its last molt. The sole purpose of the soldier is to defend the colony against enemies such as ants. All mature reproductives leave the colony at the same time, usually in the spring and sometimes in the fall. Swarmers are poor fliers and, when above ground, usually flutter a few meters and fall. Swarmers, emerging outdoors from tree stumps, railroad ties, etc., are usually not of concern and are in no way an indication that the structure is infested. After dropping to the ground, they shed their wings. Surviving males find compatible mates and then burrow into the ground to become king and queen. These termites live in nests underground and tunnel up for food, which includes the wood of homes. A very small percentage of swarming termites survive to initiate new colonies. Many are eaten by other insects, birds, etc. Likewise, swarms emerging inside a structure usually never survive. However, they are an indication of infestation nearby. Workers need high humidity to survive and will carry mud up into the wood where feeding to maintain a 97 percent relative humidity. Termites have the ability to move their colony up and down in the soil to find the optimal temperature and moisture conditions. Workers build mud tubes from the soil to the wood in structures on which they feed. Termites can feed on wood since they have protozoa in their alimentary tract (gut) that digests cellulose, the basic component of wood. Workers prefer to feed on fungus-infested wood, but can feed equally well on undamaged wood. Workers secrete food material from their mouths and anuses to feed the reproductives and soldiers. Control: In most cases, once a termite infestation has been found, control measures are best accomplished by a professional pest control firm rather than a do-it-yourself treatment. Homeowners seldom have the experience, availability of pesticides and equipment needed to perform the job effectively. Deal only with a licensed or certified pest control firm with an established place of business and a good professional reputation. Ideally the firm will belong to a city, state or national pest control association. Get at least three competitive estimates before signing a contract for control measures. Prices for inspection, treatment estimates and conditions of warranties often vary considerably. There is no need to be rushed into a termite control program. Delaying a few weeks or months makes little difference since termites feed slowly. It is more important to take your time to select a reputable pest control firm. Prevention: - Avoid moisture accumulation near the foundation. Divert water away with properly functioning downspouts, gutters and splash blocks. Ground near the foundation needs to be sloped or graded in order for surface water to drain away from the building. - Reduce humidity in crawl spaces by providing proper ventilation. - Before and during construction, never bury wood scraps or waste lumber in the backfill, especially near the building. - Remove old tree stumps and roots around and beneath the building. Never stack or store firewood lumber or other wood products against the foundation or within the crawl space. - Prevent trellises, vines, etc. from touching the house. - Concrete foundations should be reinforced to prevent cracking. - Use concrete or steel supports, steps, etc. when in contact with soil. - Borates (disodium octaborate tetrahydrate) and/or wolmanized pressure-treated wood (chromated copper arsenate) protect against termites and wood decay fungi. However, even railroad ties, telephone poles and pressure treated wood, over time, can be subject to termite attack. Mud tubes can be built over the surface or entry gained through cut and cracked ends. - Most importantly, eliminate any wood contact with the soil. A 46 cm (18 inch) gap between the soil and wooden portions of the building is ideal. Try to maintain at least 15-20 cm (six to eight inches) between ground level and porch steps, lattice work, door or window frames, etc. Pull or grade soil back away from the foundation. Wood posts and stairs embedded in concrete can also be paths of entry for termites. - Wood mulch can also attract termites, especially when damp and moist. When mulch is used, avoid contact against the wood siding or frames of doors and windows. Pea gravel or crushed stone are much less attractive to termites, ants, pillbugs, millipedes, earwigs, crickets, etc. Insecticides: To achieve termite control for long periods of time, termiticides must be applied as a continuous barrier in the soil at rates required by their labels. The goal of a termite treatment is to place an uninterrupted chemical barrier within the soil and adjacent to the foundation. Anything less can permit reinfestation by termites traveling through untreated gaps. Most pest control firms will not guarantee "spot-control" treatments, due to the high probability of termites eventually finding other untreated points of entry into the structure. A guarantee or annually renewable contract is normally purchased for at least the first three to five years after the initial treatment. Guarantees often vary from firm to firm. Treating foundation voids, under slabs, in hollow openings of concrete blocks in foundation walls, and drilling would require still more chemical and higher costs. When evaluating very low pest control operator (PCO) bid prices, always ask yourself, "How can someone treat my home for less than the cost of the chemical themselves?" "will the strength of the application be less than according to label directions?" and "are corners being cut by using less solution than required to best kill all the termites?" Effective termite control usually requires specialized equipment and often 200 or more gallons of prepared termiticide solution per house, depending on size, basement, etc. Termite soil treatment is normally a job for the professional licensed, certified pest control operator. Chemical baits: Wood or laminated texture cellulose favored by termites can be impregnated with a toxicant and/or insect growth regulator (IGR). Termite workers feed on the treated substance and carry it back to the nest, reducing or eliminating the entire colony. Termite bait stations are oriented towards a more Integrated Pest Management (IPM) approach. For more specific details, call Sentricon information (1-800-686-6200) or FMC Corporation (Firstline) (1-800-321-3621). Biological: A fungus, Metarhizium anisopliae, Strain ESCI (Bio-Blast) acts as a biological termiticide. It is odorless, vaporless, nonstaining and infected termites can pass the agent (fungus) to other termites via horizontal transfer. Bio-Blast is labeled for control of existing termite infestations in structures and their immediate surroundings and for residual protection of treated wood. Spray effectiveness is enhanced when applied to many foraging termites. Treated termites return to the colony, spreading the biological active ingredient to others. Treatments can be made both indoors and outdoors.
Adapted
from the Ohio State University Extension, 1999
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