The discovery of termites in your home or other building can be terrifying. Termites work secretly inside walls, and there is no easy way to know how much damage has been done or how large or extensive the infestation is. The unanticipated cost of treatment and repair can be shocking.
When termites are found or suspected, request a termite inspection of the house and property by experienced pest management companies working in your area. Contact at least three companies licensed by the Iowa Department of Agriculture and Land Stewardship and request inspections, written estimates, and references. Multiple inspections will confirm the existence of a termite infestation and allow you to compare service proposals.
There are no easy answers when choosing termite control for your home. There are several different treatment methods available; all are effective, and there is no one "best" treatment. Treatments should be tailored to your home and situation and the extent of the known infestation. Termite control companies chose a treatment method according to experience and company preference. Prices and offered treatments may vary widely, complicating comparison.
Take your time. Termites damage wood slowly. Emotionally, you might want something done immediately, but taking time to make an informed decision is better than making a hasty one. When comparing prices, consider both the initial treatment price and renewal fees.
Homeowner Actions to Avoid Subterranean Termites
Treating a home for termites is not a do-it-yourself project. Termite treatment requires specialized equipment, knowledge, and skills to protect your home effectively. Attempting to control termites on your own is not recommended, but here are things you can do to help prevent a termite infestation:
- Repair known structural and plumbing leaks
- Keep mulch and landscaping at least 6 inches from the house foundation
- Remove trash and debris from around the home
- Remove dead tree stumps from the yard
- Keep firewood stacked several feet away from the structure
- Ensure gutters and downspouts are working, and that water is directed away from the foundation
- Regrade the soil surface so that it slopes and takes water away from the house
- Correct any situations where wood is directly in contact with the ground contact (porches, decks, steps, etc.)
- Repair siding, brick veneer, or foam insulation so it does not extend below the soil surface
Professional Control of Subterranean Termites
There are three basic methods of termite control and prevention: injected insecticide solution, baiting, or a combination of the two. Termite treatments can be done as prevention before termites begin to feed inside the house or as a cure to stop activity that has already started.
1. Liquid insecticide solution injected into the soil around the house
For over 50 years, homes and other structures have been protected from termite damage by injecting insecticide solutions into the soil around or under the buildings. These efforts form vertical and horizontal barriers of treated soil around the structure. The specially formulated insecticides used for this are called termiticides.
A complete barrier treatment may require hundreds of gallons of termiticide solution injected from the soil surface to a depth of 3 to 5 feet into the ground alongside the foundation and beneath concrete slabs (basement and garage floors, patios, sidewalks, and driveways).
Before 1999, termite soil treatments relied on repellent termiticides that turned away termites that were tunneling through the soil adjacent to the structure. Several repellent termiticides are still registered for use against termites. Termites avoid the soil treated with repellent termiticides and forage for wood elsewhere without being killed. Application of repellent termiticides must provide a thorough, continuous, and unbroken chemical barrier around and under the structure to block all routes of termite entry.
Non-repellent termiticides became available about 2000. Termites do not detect these chemicals in the soil and continue to travel through the treated area. The termites are killed, or their behavior is changed by contact with the treated soil. Slow-acting active ingredients allow the toxicant to be transferred back to the colony by foraging workers and shared with other members of the colony.
Pest control operators may use repellant or non-repellent termiticides depending on the situation. All termiticides can successfully protect the structure when used correctly, according to label directions. Liquid termiticide barriers will remain effective in the soil for approximately 5 to 10 years, after which time re-treatment may be necessary.
A liquid termiticide perimeter barrier is typically applied to the entire perimeter of the structure, including under sidewalks, patios, and driveways. Spot treatments (for example, along only one side of the house) may be performed at the discretion of the pest control company.
2. Bait treatment
Termite baits, available since approximately 1995, consist of an appealing and acceptable food material combined with a very slow-acting toxicant. Termite baits contain tiny amounts of pesticide that is active up to several months. Control depends upon foraging termites finding the bait, feeding, and carrying it back for transfer to other colony members during the normal process of food exchange within the colony. Successful termite bating requires planning, patience, and persistence.
Baiting causes a gradual decline in termite numbers and suppresses the colony population or may eliminate the entire colony by attrition. Either way, the structure is protected by ending the termite feeding within the building. The time frame for control using baiting depends on the product selected, application timing, the time to discovery by the termites, the amount of feeding, colony size, and the use of other control measures.
Termite baits are dispensed through plastic boxes and tubes called bait stations. In-ground stations are buried just under the soil surface around the perimeter of the structure at manufacturer-specified intervals. Termites find the stations during their random search for new food sources. Stations containing untreated wood or other cellulose material may be used to monitor for termite presence before placing the active ingredient in the bait stations. After termites "hit" the monitoring station (that is, make a connection between the bait station and the colony), the monitor is replaced with a food that contains an undetectable amount of toxicant that workers eat and take back to the colony.
Above-ground stations (boxes or sachets) are used indoors where termite feeding activity or tubing is accessible (for example, on mud tubes or damaged wood). Above-ground stations complement the in-ground baits and may accelerate the bait consumption by the colony. But, above-ground baiting is not possible in all situations.
The active ingredients in termite baits are insect growth regulators (IGRs) that disrupt normal insect growth and development. Current bait ingredients block insect growth during the molting process. A comprehensive baiting program seeks to maintain a termite-free condition through ongoing monitoring and rebaiting as needed.
Do-it-yourself termite baits are available to homeowners but are not recommended for whole-house termite protection. Limited spot treatment of lower value structures (sheds, fence posts, landscape timbers, etc.) may be practical, but attempting an amateur approach to protecting something as valuable as a home is not prudent. Application of a limited number of bait stations coupled with a lack of a detailed understanding of termite biology and behavior will severely limit the chances of success and likely result in a false sense of security. Consult experienced, well-trained pest management professionals to coordinate a successful, long-term termite control program.
3. Combination of liquid termiticide and baiting
A combination of barrier and bait treatments may be appropriate in some situations. For example, a liquid termiticide application may be made for quick control and bait stations installed for long term monitoring. Traditionally, barrier treatments provide faster, if not immediate, results that may be desirable in some situations such as a real estate transaction.
See the Virginia Tech Institute for a detailed comparison of the advantages and disadvantages of the different termite treatment types. https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/444/444-500/444-500_pdf.pdf
Control of Drywood Termites
First, evaluate the level of infestation and the value of infested furniture to decide if the furniture should be discarded or treated. If you choose to salvage infested furniture, hire a pest control professional to inject insecticide dust or spray into the termite galleries. Professionals have specialized equipment that allows the insecticide to be injected into infested wood either through existing holes or through small holes drilled through the wood surface. Repeat treatment may be needed to eliminate the infestation. Fumigation in a vault or tarp is an option only available to professionals.
Temperature extremes may be a practical alternative. Infested furniture (or pieces) that can be heated to 120 degrees F for several hours will be free of termites. Similarly, a rapid lowering of the temperature (from room temperature to below freezing) may eliminate the termites. Freezing could be accomplished by moving the furniture to a large, walk-in freezer or waiting until a freezing winter day and moving the furniture from a warm house into a garage or unheated porch for several days. Either environmental treatment will require checking furniture joints to see if re-gluing or tightening screws is needed.