|BIOLOGY AND CONTROL OF SUBTERRANEAN TERMITESMichael Waldvogel – Extension Entomology||Insect Note – ENT/rsc-20|
Termites are the major wood-destroying structural pests in the southern United States. According to some estimates, over $2 billion are spent annually in the U.S. controlling or preventing termite infestations. In North Carolina, our main problem is with subterranean termites, i.e., termites that normally live below ground and may move up into a structure where they cause damage.
Termites are “social insects”, i.e., they live in a nest or colony which is typically found underground, often near a tree, stump, wood pile or other source of ‘food’. Each colony contains a king and queen who are brown in color. The queen is able to lay thousands of eggs each year. There are also soldier termites which have large heads equipped with large mandibles (“jaws”). The soldiers protect the colony from invaders (such as ants). The majority of the colony consists of thousands of whitish workers who have various jobs within the colony. Some workers take care of the queen and the newly hatching immatures (sometimes called “larvae”). Other workers forage (search) for food. The foraging workers are the ones that we find infesting wood. As the colony grows, the workers expand the nest and their feeding area. A mature colony will contain 200,000 to 2,000,000 workers, although many colonies contain as few as 50,000-60,000. Studies have also shown that termites from a single colony may forage across an area of one-third acre and travel over 200 feet from their nest. One acre of land may support several termite colonies (although this doesn’t mean that all of them are invading your home!). A large termite colony does not usually occupy a single underground nest. As the foraging area expands the colony actually splits to form several smaller “nesting sites“.
|SIGNS OF TERMITE ACTIVITY [ TOP ]Without a periodic inspection of your home, termite activity can remain undetected for years. Some signs of their activity show up unexpectedly, while others are discovered by accident or during renovations. Here are some key signs of a termite infestation:Swarming –
A termite colony matures in 3-5 years and begins to produce swarmers (winged adults). In North Carolina, we have at least three species of termites that begin swarming in late winter and continue into September or October. Swarming usually occurs during the day, particularly on warm days following rain. Swarmers found outdoors near tree stumps, landscape timbers, etc., are not an indication that your house is infested, but they serve as a reminder that termites live around us. When swarming occurs indoors, it usually means that you have an infestation somewhere within your house. Several species of ants also swarm at the same times of the year as termites. Winged termites and ants look somewhat similar, but you can tell them apart by certain features. If you’re not sure whether you have termites or ants, show them to a pest control professional or bring specimens to your county Cooperative Extension Center for identification.Mud tubes [ TOP ]
Unlike ants, termites do not roam around out in the open. They will either tunnel through wood (or other material) or else travel inside pencil-size (or larger) mud tubes that they build from soil, wood particles and other materials. You will find these tubes on foundation walls, floor joists or other parts of the house. Tubes may also hang from the floor system (see picture below) or may be found protruding from cracks between boards and beams and even through holes termites may chew through sheet rock on walls and ceilings. Break open the tubes to see if termites are still active. An empty tube doesn’t necessarily mean that termites are gone; they may have simply abandoned this particular tunnel. Termites often rebuild damaged tubes, which is another indication of current activity. ‘Old’ tubes are dry and crumble easily, leaving behind “etching” on the surface that may be visible for years (an indication that a house had termite activity at some time). Without knowing the inspection history of the house, it is impossible to tell or guess at the age of tunnels or etching.Tubes that are found on ceilings or on the second floor of buildings may indicate that you have a “secondary” or aboveground (“aerial”) infestation, i.e., the termite colony actually lives in the building and the termites are traveling up from the soil. Mud tubes built by an aboveground colony usually contain materials other than soil, e.g., wood and sheet rock or whatever the termites are feeding on. Secondary infestations occur when there is a serious moisture problem or leak somewhere within the structure. In such situations, a thorough inspection may require removal of siding or interior wallboards, etc. More importantly for you, secondary infestations cannot be controlled with the usual soil treatment (see below). Finding and correcting the moisture problem is the first step to eliminating the termites.
Termite Injury [ TOP ]
We tend to think of termites as feeding/injuring wood only. Termites actually feed on almost anything that contains cellulose, the main component of wood, including wood paneling, paper products, cardboard boxes, art canvases, the paper covering of sheet rock, carpeting, etc. While foraging and feeding, they may tunnel through non-cellulosic materials, such as plastic and foamboard. According to some research, a colony containing 60,000 workers could consume the equivalent of one foot of a 2″ x 4″ piece of lumber in slightly over 5 months. In reality, the amount of damage that termites cause depends on many factors. In areas with cold winter temperatures, termite activity (and feeding) often declines, but does not necessarily stop. If the termites are well-protected from colder temperatures (e.g., underneath a slab), then activity may continue year-round. From a practical perspective, serious termite damage usually takes about 3-8 years.
Look for these signs of termite feeding:
There is no accurate method for determining the age of recently discovered damage. You need some reference point, i.e., some point in time when it was known that there was no damage to this particular wood. This is one reason why annual inspections (and keeping your records of these inspections) are invaluable.
|CONTROLLING TERMITES [ TOP ]What should you do if you think or discover that your home is infested with termites?
If you have a termite protection contract, contact the pest control company immediately and arrange for them to check out the problem. If you do not have a termite contract, call 2-3 (or more) companies and have each one inspect your home and provide you with the details of their findings and any recommendations for a course of action to correct any termite problems that they found. Take your time to evaluate their proposals and determine your best course of action. Termites do not cause significant damage in a short period of time, so spending a few extra days or even a few weeks will not make any real difference in terms how much damage occurs.
There are several important questions you need to ask:
You can find additional information in the publication ENT/rsc-3, Tips on Selecting Pest Control Services.
|Typical Termite Treatments [ TOP ]Simply spraying swarmers or the surface of accessible infested wood may kill the termites that you see now, but it does not stop the infestation nor does it protect your house from further attacks by termites. The most common type of termite treatment involves a “trench and treat” where a liquid insecticide (termiticide) is applied to the soil surrounding critical areas of your house. The most critical area needing treatment is the foundation wall (see the image to the right). The soil is trenched 6″ deep and about 4-6″ wide. For houses with crawlspaces, the soil along the interior foundation wall must be treated at least within 4 feet of identified signs of termite activity. In some cases, the soil around supports (such as piers) underneath the house are also treated. In order to be effective, this treatment must extend down through the soil to the top of the foundation footer. When applied correctly, this treatment forms a continuous chemical barrier that should prevent termites from reaching the foundation and piers in your house. Current North Carolina regulations also require drilling and treating of:
You can view the state regulations (requires Adobe Acrobat®) or obtain a copy from the NC Dept. of Agriculture and Consumer Services – Structural Pest Control and Pesticides Division (NCDA&CS) in Raleigh (919-733-6100).
These specifications are the current minimum requirements for a treatment under state regulations. Some pest control companies still drill and treat the entire foundation wall and piers. Some companies offer “spot treatments”, i.e., they treat only the area(s) of the house where termites are found. A spot treatment may seem like a good idea because it costs less than a full treatment. However, there are some important points to remember. First, a spot treatment may not correct the problem. Second, except when done under an existing contract, a spot treatment often carries a very limited guarantee (or no guarantee at all). It’s your house, your money, your choice. Don’t let economics be your only determining point about how to protect your house from termites. On a new contract (treatment), any treatment procedures that will not be done according to NC regulations must be noted on an official Waiver of Minimum Standards form. You mustsign this form as part of your contract. If you are asked to sign a waiver form make sure you understand what each waived item means (i.e., what work is not being done and why it is not being done).
Another option for treatment is the use of a termite bait. These products are used differently from liquid treatments and may be used with a liquid treatment. Click HERE for more information about termite baits.
Regardless of whether you have a liquid termite treatment or a baiting system installed, remember this important point: Before you sign a service agreement or contract, read it carefully. Here are some questions to help you evaluate the proposed service:
A list of commonly-used termiticides can be found in the current edition of the North Carolina Agricultural Chemicals Manual. You can also contact the NCDA &CS for a complete list of all currently registered termiticides.
|Why not “Do-It-Yourself”? [ TOP ]Although there are termiticides available for homeowner use, we do not recommend the “Do-it-Yourself” (DIY) approach for chemical control of termites for several reasons. Many products have instructions for spraying the surface of infested wood. Simply spraying swarmers or the surface of accessible infested wood kills the termites that you see at that time, but it does not protect the interior parts of that infested wood nor does it protect your house from further termite attacks. If you see termites in one area, don’t assume that it’s the only infested area or that what you see is the extent of the problem in that area. Only a thorough inspection can show if the termites are also feeding someplace else and even then, termites could be infesting your home in areas that are inaccessible (and uninspectable. Also, simply spraying the soil surface and/or exterior foundation wall is not going to stop a termite infestation below ground and possibly entering your home from below ground.What is needed to do a liquid termite treatment correctly?
There are several products including a termite bait, sprayable foam, and a granular insecticide available for consumer use. READ THE LABELS ON THESE PRODUCTS THOROUGHLY AND CAREFULLY BEFORE PURCHASING AND/OR USING THEM. The product labels all contain a statement to the effect that the use of these products is NOT a substitute for mechanical alteration, soil and foundation treatment, but merely a supplement. In other words, these products will kill termites but they will not eliminate an active termite infestation in your home nor will they product your house from future termite infestations.
|Difficult or problem situations [ TOP ]There are situations where a conventional termite treatment is particularly difficult, undesirable, or even impossible. Some situations call require special handling, others may require alternative approaches. For example:
In these situations, there are few alternatives such as termite baits or mechanical control. Termite baits are discussed in the publicationENT/rsc-20.
Although local or “spot” wood treatments stop termite activity in the treated area, they are not complete termite treatments and they will not stop termites from attacking wood in other areas. One treatment option uses the chemical disodium octaborate tetrahydrate (DOT). This borax-derived chemical is applied to critical wooden structural components in the crawlspace and parts of the framing in a house under construction. Data provided by product manufacturers suggest that termites do not extend their tubes over treated wood nor do they cause any structural damage. However, depending on the type of construction involved, it may be possible for termites to bypass this treatment and attack nearby untreated wood such as baseboard molding, trim, etc. Chemicals that are suitable for wood treatments are listed in the current edition of the NC Agricultural Chemicals Manual.Fumigation
In North Carolina, structural fumigation (sometimes called “tenting”) is rarely used for our common subterranean termites. Most residential fumigations are performed for drywood termites, which are relatively uncommon in North Carolina, or for wood-boring beetles particularly in log homes.Annual Contracts [ TOP ]In most cases, the termite treatment on your house includes a one-year termite protection warranty from the pest control company. After one year, you must decide if you want to continue your contract. The cost of a renewal for a house that was treated with a liquid termiticide is typically between $85-$200, depending on the size and construction type of the house and perhaps the type of guarantee (explained below). The most frequently asked question is “Do I really need the annual contract?” Essentially, this is a matter of personal choice, i.e., how much “peace of mind” do you want in terms of protecting your home from termites. Remember: termites are always around us and always looking for “food” (wood). That fact alone does not mean that they are constantly attacking your house. It simply means that there is always some chance that termites might find their way unseen into your house.
The US Environmental Protection Agency requires that termiticide manufacturers prove that their chemicals can remain effective in the soil for at least five years. In most situations, these chemicals usually last longer when applied properly. However, this 5-year requirement is not a guarantee that termites cannot (or will not) invade your house within a five year period. A number of factors such as the quality of home maintenance or the disturbance of the treated soil during renovation or landscaping activities can disrupt the chemical barrier and provide termites with opportunities to invade. These renewals are somewhat like medical insurance policies. You pay to protect your home against the possibility of termite attack. An annual contract can be an effective way of preventing termites from causing significant damage over the years. Likewise, this 5-year requirement by the EPA does not mean that the chemical is totally ineffective after 5 years. This last point will be addressed down below under “Booster Treatments”
An annual contract does not mean that the pest control company re-treats your house every year. Unless there is some evidence of termite activity in the house, annual treatments are actually illegal under most termiticide labels (and therefore illegal under both state and federal law). With a termite protection contract, the pest control company inspects (or should inspect) your house for termites annually. If they find evidence of termite activity or if you find evidence of termite activity, then the company takes some appropriate measures, usually a local or ‘spot’ treatment of the infested area. You should not have to pay for any additional treatment to correct a termite problem; that cost is covered by your annual fee. In return, the company expects you to do your part in maintaining your house in a condition that does not increase likelihood of termite problems. For example, routine home maintenance helps prevents moisture problems or other conditions that are conducive to termite activity in the area, i.e., if termites find such area, they are more likely to remain active or expand their activity in that area. Make sure that the termite inspector explains any problem areas that he/she finds during the inspections so that you can correct these problems as soon as possible. In some cases, your failure to correct reported problems may void your termite protection contract. If you’re not home when the house is inspected, the inspector should leave some sort of notice or report about his/her findings. If you’re not clear on the results, call the company’s office and ask them to explain if anything important was found.
Does my contract coverage termite damage?
Read your contract carefully. If you have had the contract since the house was built (and presumably it was not built with termite damaged wood), then the damage should be covered by the terms of the contract. This assumes that you have upheld your part by not disrupting the treated soil or allowing termite-favorable conditions to prevail. On the other hand, if you buy an previously-owned home that has not had a contract (regardless of when it was last treated), then the contract likely excludes existing damage. For example, if in the course of renovating your house you find termite damage behind a wall but there are no termites present, this situation is usually considered to be “existing damage” (prior to the start of your contract) and therefore it is excluded from your repair guarantee because there is no way to determine if the damage occurred before or after the start of your contract. We are not aware of any scientifically sound way to precisely determine the age of termite damage. This exclusion is not simply an excuse for the company to avoid their contractual obligations to you. It is legitimate issue that you need to understand and should have it explained to you BEFORE you sign the contract. For your own protection, make sure you receive (and keep) records provided to you by the company. Also, if you sell your house, you should pass these records onto the buyer. Important records to keep include:
One other important point of note. Your termite protection contract is strictly that – a contract for termites and termite control. Unless specified otherwise, your contract does not include inspections or coverage for other wood-damaging pests, such as carpenter ants orpowderpost beetles (although the inspector may note such problems and bring them to your attention), or even other types of pests such as millipedes, cockroaches, etc.
For additional advice on consumer protection and your termite contract, read the publication A Homeowner’s guide to Termite Control Service Agreements and Warranties by the NC Dept. of Agriculture & Consumer Services.
|Preventive Treatments for TermitesCurrent North Carolina Building Code requires that all residential structures under construction have some sort of termite protective treatment. The particular type termite treatment does not have to be a liquid treatment. It is a matter of choice by the builder and/or owner but it must be a method approved by the NC Department of Agricultural and Consumer Services. Additional information about preconstruction treatments is available at the following links:Termites – Preventive Measures for New ConstructionPre-Construction Termite Control (NCDA&CS)
As mentioned previously, modern termiticides applied properly to the soil are typically effective for 5-10 years. This doesn’t mean that after 5 or 10 years every termite in the neighborhood makes a mad rush at your house. It’s simply that the odds favor the termites eventually finding their way in at some point, depending in large part on how you maintain your house and property (see Reducing the Threat of Termites Around Your Home).“Booster Treatments”
As mentioned earlier, EPA currently requires that liquid termiticides be effective for 5 years. This does not mean that the chemical is completed gone after five years. Many people wonder if they need to have their house retreated for termites after a certain number of years have passed. If you have a termite protection contract, some companies may require a “booster treatment” after some period of time in order to maintain your guarantee. Such a requirement would be specified in your original contract; so read your contract carefully BEFORE signing it. These treatments are usually partial retreatments, such as just treating the soil around the foundation. More importantly for you, the cost for this treatment is usually not covered by your current contract and you will have to pay for the work (often $600-$1200, depending on the size and complexity of the construction). If you decide to discontinue your contract you’ll either be without a termite protection policy or you will need to find another company which may or may not require a similar treatment. At that point, you’re back “square one” and evaluating what type of service and contract the company (or companies) offer. As an option to having a booster treatment, the company may offer to continue your current contract but at a significantly higher annual renewal (perhaps 25%-50% higher). Again, read your current contract to see if there are terms concerning booster treatments and/or increases in your annual fee.An important point to consider if you need to decide on getting a booster treatment or switching companies – if you currently have a repair warranty and want to continue with one, you will again have the exclusion of “current/old” damage if you switch companies. In general, if a repair contract is that important to you AND you have had your house under continuous contract with the same company since the day it was built, then you’re probably better off staying with that original company because ANY termite damage that is found must have occurred during the period of your coverage and therefore it IS covered by your repair warranty.
Other than with a contract requirement, a pest control company may only suggest that you get a termite treatment if you do not have an identified termite problem. They cannot tell you that need one. If you don’t have a termite problem, then a preventive treatment is a matter of YOUR choice. You can follow the old adage of “if it ain’t broke…..” However, it falls to you to be responsible for knowing “when it’s broke”, which is why annual inspections are valuable. You can simply wait until a problem occurs and then have a treatment done at that time. On the other hand, if it would make you sleep better at night knowing that your house has been treated and you have some sort of contract, then it’s your money, your house, your decision.
|Non-Chemical Control of Termites [ TOP ]Alternatives to chemical control of termites (i.e., to control an active infestation) are limited. Long term, non-chemical approaches to termite control focus on prevention. Here are a few approaches that may help with, but not necessarily prevent or likely eliminate, an active termite infestation.|
|Mud Tube RemovalState regulations require pest control operators to remove termite tubes as part of a complete liquid termite treatment. Removing the tubes provides a way to determine if a termite infestation remains active after treatment or if the termites reappear in the same area later.Scraping away mud tubes as the sole means of control can be impractical and is probably unwise in many cases (such as with slab construction where much of the termite activity may be inaccessible). The tubes are an indication that termites are active around the house. What you can’t easily determine, even with a careful inspection, is whether termites may be active in a foundation or wall void or some other visually inaccessible area of your home.|
|Debris RemovalAlthough it’s convenient, it is not a good idea to turn your crawlspace into a general storage area, particularly for items made of wood, cardboard or paper which can serve as food for termites. The same problem arises when tree stumps are left under houses during construction. State regulations require that liquid termite treatments (but not bait treatments) include the removal cellulose debris of a size that can be removed with an ordinary garden rake. Removing the debris helps reduce food resources that could be used by termites. This topic is discussed under preventive measures.|
|Pathogenic FungiTermites live in an environment that is filled with microorganisms, including many that are lethal to them. One such pathogenic fungus,Metarhizium anisopliae has been developed commercially into a product called BioBlast®. This product, which contains fungal spores, is applied to accessible termite infestations aboveground. The spores germinate and the fungus penetrates the insect’s cuticle (outer skin). The fungus grows inside the insect’s body and eventually kills it. Infected termites coming in contact with other members of their colony can mechanically transfer the fungus to them. BioBlast® is not labeled for application to the soil and there are no data to suggest that such soil applications would be effective. Because the product is labeled for aboveground applications only, it has not been used significantly in North Carolina.|
|Mechanical BarriersA great deal of research is going on concerning termite-resistant building materials. In most cases, these materials are most easily installed in new construction; however, some materials can be fit to existing houses (although the cost may be significant.) For more information about mechanical barriers see ENT/rsc-25, Preventive Measures for New Construction[ TOP ]|
|PROBLEMS OR QUESTIONS? [ TOP ]If you are not satisfied with the service you are getting from a pest control company or you feel that your questions are not being answered, you have some recourse. First, you should talk to the company’s manager or owner to make sure that the problem is not simply a matter of misunderstanding or miscommunication. If you’re still not satisfied with the response you receive, then contact theNorth Carolina Department of Agriculture & Consumer Services (919-733-6100) for assistance.OTHER RELATED WEB PAGESReducing the Threat of Termites Around Your Home
Structural Pest Control Brochures (NCDA&CS)
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|Pest information and control recommendations presented here were developed for North Carolina and may not be appropriate for other states or regions. Any recommendations for the use of chemicals are included solely as a convenience to the reader and do not imply that insecticides are necessarily the sole or most appropriate method of control. Any mention of brand names or listing of commercial products or services in the publication does not imply endorsements by North Carolina Cooperative Extension nor discrimination against similar products or services. All recommendations for pesticide use were legal at the time of publication, but the status of pesticide registrations and use patterns are subject to change by actions of state and federal regulatory agencies. Individuals who use chemicals are responsible for using these products according to the regulations in their state and to the guidelines on the product label. Before applying any chemical, always obtain current information about its use and read the product label carefully. For assistance, contact the Cooperative Extension Center in your county.Distributed in furtherance of the acts of Congress of May 8 and June 30, 1914. North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.|