Subterranean termites are a natural part of the environment in Louisiana. Native subterranean termites live everywhere in the state. As of the first of 2005, the invasive Formosan subterranean termites are found in about one-half of the parishes. They occur in parishes containing and south of Interstate 10. Additionally, Formosan subterranean termites occur in Beauregard, Ouachita, Rapides, Sabine and Vernon parishes. These termites have not completely spread throughout some of these parishes, but they are being moved to other places.
Subterranean termites eat cellulose (wood, paper and their products). Thus, they play an important role in recycling wood; however, they cause serious problems when they try to recycle wood in homes. Subterranean termites must eat cellulose to survive and are constantly searching for wood, paper and their products used by humans. Therefore, humans must constantly seek to prevent termites from eating the wood, paper and their products they use.
Protection of wood, paper and their products from subterranean termites requires integrated pest management. Integrated pest management of subterranean termites involves several areas. Each of these areas is an important part of the integrated pest management system. In practice, perfection in any one of these areas occurs rarely. Do NOT rely on one area as your only means of managing subterranean termites. For example, do NOT rely on insecticides alone to manage subterranean termites. Remember, thousands of subterranean termites are searching unceasingly for food: wood, paper and their products.
IPM of subterranean termites in homes involves two situations: the building of houses and houses that have been built. There are a large number of things that may be done and many more opportunities to manage subterranean termites during construction of the house than after the house is built. Once the house is built, opportunities for managing subterranean termites that were not used are lost and cannot be regained without rebuilding the house. Thus, humans involved in any phase of building a house have an additional responsibility to protect the house from subterranean termites.
Integrated pest management of subterranean termites includes every aspect of a house throughout its lifetime. The starting point and first area is land preparation. Do not bury wood cleared from the land, because this is burying food near the house. Slope the land so that water runs away from the house. Notice, subterranean termites were already living and eating wood in the area cleared (they were here first!). Now their food is gone, and the best remaining food supply is the house.
The second area is architectural design. Design the house to eliminate wood-to-soil contact, eliminate all sources of moisture in or around the house, eliminate hidden access by subterranean termites, treat and inspect the structure easily, and use termite-resistant materials. Do not design a flat roof.
The third area is pretreatment of the soil. This involves treating the soil that will be under the slab or piers with a labeled, liquid insecticide. A baiting system would not be included as pretreatment of the soil because the stations could be removed at any time, and protection would no longer be provided. The soil cannot be treated when it is too wet, too dry, frozen, covered in plastic or after the rebar is in place. Take the time to ensure a proper treatment. Do not disturb the soil once it is treated. For example, walking on the treated soil will break the barrier. The soil under a slab and, to a lesser degree, under piers is highly protected. Insecticide in these protected sites is thought to break down more slowly than insecticides in soils exposed to the weather near the slab. There is only ONE opportunity to treat under slabs and piers.
The fourth area involves barriers. Today, the most commonly used barrier is the slab. Prevent cracks in the slab by preparing the soil under the slab, let the soil settle and use the proper mix and thickness of cement. Any crack or hole in the slab, including holes for pipes and bathtraps is a route of entry for subterranean termites. Other barriers include steel mesh barriers, insecticide-impregnated materials and rocks of a narrow, specific size range.
Put steel mesh barriers around pipes that pass through the slab and over holes in the slab. Use solid piers or place piers made of brick or with voids on solid concrete pads. Do NOT put blocks with voids on the ground. Additionally, termite shields may be used. Termite shields do not stop termites; they only force termites to show themselves. Do not put holes in termite shields because the termites will go through the holes and not around the shields.
The fifth area is materials. Use termite-resistant materials. The single most important tool for managing termites is properly pressure-treated wood. Borates are good preservatives for pressure treating wood to be used in a house. Borates will completely penetrate 2 x 4s made of southern yellow pine sapwood, the wood most often used in construction in Louisiana. When borates are sprayed on wood, they penetrate the wood about ¼ inch. Termites will eat the untreated centers. Wood items that are not available with proper pressure treatment (cabinets, doors, door frames and window sills, etc.) and wood items ½ inch or less in thickness may be treated with a topical application of borates on all sides. Paper such as on the back side of a wallboard may be lightly sprayed with borates. (Do not wet the wallboard enough to damage it.)
Non-wood materials (hardy board, concrete, plastic, steel, etc.) may be used and will not be eaten by termites. Consideration must be given to the building properties of wood versus non-wood materials. Such considerations include the initial cost of materials, environmental and energy costs of the materials from their production through their disposal, and the insulation value of the materials. Termites will tunnel over non-wood materials and properly pressure-treated wood with the possible exception of borate-treated wood to eat important documents, books, picture frames and any other untreated cellulose material.
The sixth area is construction. Many things may be done during construction to manage subterranean termites. Build the house to eliminate wood-to-soil contact, eliminate all sources of moisture in or around the house, eliminate hidden access by subterranean termites, make the structure easy to treat and inspect, and use termite-resistant materials. Make sure the land is prepared properly, the pretreatment is done properly and the slab is done properly. Do not leave form boards, grade stakes, concrete and bricks around the slab or driveways. Do not use wood between cold and expansion joints. Make sure at least 6 inches of slab is showing after landscaping. Do not fill porches with soil. Do not bury wood or other construction materials such as leftover concrete and brick. Use barriers to cover holes in the slab. Use snap-on baseboards.
The seventh area is post-treatment. Within one year after treating under the slab, treat the soil next to the slab. Dig a 4-inch by 6-inch trench, treat this trench and the replaced soil at labeled rates, making sure all of the soil is thoroughly treated. Drill and treat all joints where driveways, patios, etc. touch the slab. Baits may also be used.
The eighth area is maintenance. Maintenance is needed continually over a long time. Ideally, inspect the house for signs of termites every two months. Alternately inspect the house in the spring, summer and fall. Do NOT break the insecticide barrier around the slab or piers. Do NOT put ANYTHING on the treated soil, move the treated soil, allow plants or objects to touch the house, allow water to be continually placed on the treated soil (drain pipes, sprinklers) or allow high pH cleansers to fall on the treated soil.
If the barrier is broken, retreat the soil promptly. Currently, most of the liquid insecticides used to treat the soil have a life expectancy of 5 years. Retreat the soil after the life expectancy of the product used is past. If insects are found infesting the house, collect the insects and have them identified. This allows determination of proper treatment. Maintain the structure so that water is not provided to termites (leaks, clogged gutters, etc.). If soil is replaced, be sure it is treated. Make sure all additions to the house are constructed following the procedures for managing subterranean termites.
The ninth area is landscaping. Keep plants a minimum of 3 feet from houses. Do NOT disturb the treated soil. Use termite-resistant materials. Do NOT transport termite-infested wood, plants, mulch or soil. Mulches containing cellulose provide food for termites. All mulches modify temperature and moisture conditions favorably for termites.
The tenth area is trees and woody plants. Formosan subterranean termites eat the centers of live trees and woody plants. Inspect these plants for signs of termites and treat infested plants. Remove stumps and dead wood.
The eleventh area is containment and disposal. Everyone has a responsibility to prevent the spread of Formosan subterranean termites. They may be moved in wood, paper and soil. Do NOT move such materials from infested areas to uninfested areas without being certain that the materials are not infested. Do NOT move infested materials without treating them.
The Formosan subterranean termite is a serious pest. It cannot be eradicated with current technology, but it can be managed by following these guidelines.