& Community Pests
|Department of Entomology||
| BIOLOGY AND CONTROL OF SUBTERRANEAN TERMITES
Michael 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:
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
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
the structure. In such situations, a thorough inspection may require
removal of siding or interior wallboards, etc. More importantly for
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.
Injury [ TOP ]
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)
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 must sign 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?
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 publication ENT/rsc-20.
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?
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 or powderpost 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.
Current 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:
Pre-Construction Termite Control (NCDA&CS)
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 Removal
State 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 Removal
Although 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.
Termites 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.
A 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
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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 the North Carolina Department of Agriculture & Consumer Services (919-733-6100) for assistance.
OTHER RELATED WEB PAGES
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.
Last revised - March 2007