Termite Treatment

Subterranean termites | Treatment methods

Liquid Termiticide Applications

Liquid termiticides are usually applied completely around and underneath a structure covering all areas where termites might gain access. For new construction, this is accomplished by treating the graded soil before the slab is poured. For an existing building, the perimeter of the foundation is trenched and drilled then treated with termiticide. The goal of the treatment is to put a chemical barrier between the termites in the soil and the structure above. The chemical barrier can also affect those termites inside a building by preventing their return to the soil. In many cases these termites will die of dehydration.

Repellent Termiticides

There are several repellent termiticides on the market. These termiticides are all pyrethroids. Pyrethroids are fast acting nerve poisons that are highly toxic to termites but have low toxicity to mammals. Some of the pyrethoid termite products include Dragnet FT, Cynoff, and Talstar (FMC Corporation, Philadelphia, PA) and Demon and Prelude (Syngenta, Inc., Greensboro, NC). The pyrethroids are also highly repellent to termites. In most cases, they are so repellent that termites foraging under the soil will avoid coming into contact with the termiticide and forage elsewhere.

There are advantages and disadvantages to repellent termiticides. One advantage is that a complete barrier will effectively keep termites from coming into the structure. Also, the pyrethroids used for these barriers are relatively inexpensive and last for several years. The disadvantage is that termites are able to detect these termiticide barrier in the soil and avoid lethal contact with them. This is important because applying a perfect barrier under a fully constructed house is very difficult. Construction features, plumbing lines, and landscaping are just a few of the obstacles that hinder liquid termiticide application. Because of these difficulties, there are often gaps in the treatment where the termiticide was not applied completely. Eventually, foraging termites may locate these gaps and gain access into the structure. If these termites find the structural wood, they will tunnel back through the untreated gap and recruit other termites into the building.

Non-Repellent Termiticides

At the time of this writing there are two non-repellent termiticide treatments available on the commercial market. Both are nerve poisons like the pyrethroids, but they attack different sites on the nerve. These chemicals are not repellant and termites cannot detect them in the soil. Therefore, the termites tunnel into the termiticide while foraging, contact the chemical, and die.

Premise (Bayer Corporation, Kansas City, MO.) contains the active ingredient imidocloprid. Imidocloprid is unique because it not only kills termites that contact a lethal dose, but it also kills them at doses too small to cause immediate death. If a termite contacts even a very small amount of imidocloprid it will become lethargic and forget to eat and feed other termites. It will also forget to groom itself so it soon becomes infested with soil fungi. The termite eventually dies as a result of these indirect symptoms of imidocloprid exposure. A disadvantage to Premise is that it is somewhat more expensive than the pyrethroid termiticides and in some cases may not last as long in the soil.
Termidor (Aventis Environmental Science, Montvale, NJ) is the newest termiticide on the market. Termidor became available in February 2000 for use as a non-repellent termiticide. The active ingredient is fipronil. Fipronil is unique in that it can be transferred from one termite to another through contact and trophallaxis (communal feeding). This allows it to affect more termites than those that contact the chemical directly. The advantage of this product is its long-term effectiveness in the soil. Test data indicate that fipronil may be effective longer after the initial application than other liquid termiticide products. A disadvantage is that Termidor is more expensive than other liquid termiticides.

Liquid Termiticides

Advantages

Intended to provide immediate protection for the structure
Relatively inexpensive compared to baiting systems
Lasts multiple years in the soil
Non-repellent termiticides eliminate the problem of termites locating "gaps" in the treatment

Disadvantages

Even the most conscientious pest control operator will have difficulty putting down a chemical barrier that is free of "gaps." Gaps in repellent termiticide applications may later provide access to termites.
Liquid termiticides applied within 50 feet of a body of water, well or cistern are a water contamination risk. However, it is not illegal to use liquid termiticide near these areas. A treatment method where the soil around a structure is removed, treated, dried and replaced is frequently used where water contamination is a concern. However, this treatment method does not eliminate the risk of the chemical leaching into a water source over time. In areas of potential water contamination, termite baiting is a better option.

Subterranean Termite Baits

Termite baiting takes a very different approach to subterranean termite control than liquid termiticide application. Instead of attempting to protect a structure by creating a barrier between it and the termites, baiting targets the termites themselves. Termite baits are designed to suppress or eliminate the termite colony living in the soil.

Commercial termite bait systems are a relatively new technology. The most widely used bait products are applied very similarly. The initial installation of any baiting system involves plastic stations being inserted into the ground around the perimeter of the structure approximately every 10 feet. Inside these stations are untreated wood monitors. The stations are usually inspected every 30 to 90 days for termite activity. If live termites are found in the station, a toxic bait will be placed inside and the infested monitor may or may not be removed. The idea is to get the termites that are now feeding on the wood monitors to feed on the bait instead. Certain bait products are intended to be used by themselves, while others can be used in combination with a spot applications of liquid termiticide (applied only to areas where termites are active) or a complete liquid treatment.

Because the in-ground bait stations are placed outside the structure, they do not directly affect termites that are already foraging inside. To address these inside infestations certain manufacturers provide above-ground stations. Above ground stations are basically plastic boxes that contain a paper matrix (bait) laced with the active ingredient (toxicant). The boxes can be attached over a termite mud tube or directly onto infested wood. The termites forage inside the box and consume the paper bait.

Exterra System - This system was developed by Ensystex (Fayetteville, NC) and can be used either as a stand-alone bait or in combination with a liquid termiticide. The Exterra bait station is lined with strips of untreated wood, called "interceptors". The center of the station is left empty until termites hit the station. When the station is hit, bait is placed in the center of the station but the interceptors are left in place so that termite feeding is not disturbed.

The Exterra stations are larger than other commercial bait products so the inspection interval for the large stations can be as long as 90 days. The longer interval between inspections makes the Exterra system less expensive to maintain than Sentricon.
The active ingredient in the Exterra bait is diflubenzuron (dimilin). Like hexaflumuron, diflubenzuron is a slow acting insect growth regulator that is passed from termite to termite by trophallaxis. Diflubenzuron also interferes with termite development killing them during the molting process. Thus like Sentricon, Exterra is a colony elimination system.

Professional Termite Baiting Systems

Advantages

Baits are very environmentally friendly because there is considerably less active ingredient put into the environment compared to the hundreds of gallons of diluted insecticide used in liquid treatments.
Termite baits are ideal for use around structures inhabited by persons with chemical sensitivity.
In situations where the infested structure is within 50 feet of a well or 100 feet of a body of water, termite baits may be the only treatment option.

Disadvantages

There are no means of coaxing termites into stations that are being monitored so it may take months before baiting can begin.
Professional baiting systems are generally more expensive than barrier treatments because of the monthly inspections.
Termite baiting systems when used alone do not protect the structure directly. Termites feeding within the structure will continue to do so until the colony is eliminated or they are controlled with an above ground station.