What is a Termite Spray?
Termite sprays are a popular barrier method of termite treatment which can be broadly broken down into two classifications: repellent and non-repellent. Termite sprays for wood are generally applied directly to buildings but the best and most effective spray treatments may be those that are deployed into the soil below and around the structure to be protected from termite invasion.
Repellent Termite Sprays
Repellent termite sprays have been used for decades and are most generally used on both the structure and the soil surrounding it. As the name implies, these sprays are not primarily intended to kill the termite foragers or colony but to redirect them away from the treated structure to other food sources.
A class of chemicals called pyrethroids is the most common ingredient used in repellent sprays. Pyrethroids are synthetically produced to mimic the naturally occurring active chemical in chrysanthemum flowers —a natural termite repellent. Sprays containing pyrethroids can be identified by looking for these names in the ingredient labeling
Pyrethroids are considered generally safe for humans and mammalian animals in low doses, but pose a significant toxic risk to aquatic animals and “good insects” such as honey bees. They also pose a great health risk for chemically sensitive people, and those who have previously experienced cyanide exposure.
Pyrethroids are able to penetrate the exoskeletons of termites and have a paralytic effect on the individual termite organism. Those coming into direct contact with pyrethroid chemicals in wood are soil are generally killed, but the greatest efficacy of this class of sprays is due to the fact—somewhat contrarily—the termites can detect the presence of the pyrethroid chemical—and so will avoid structures that have been treated with it.
Pyrethroid sprays are generally relatively inexpensive in comparison to other termite treatments and remain active in the soil and treated structures for several years. However, one of the drawbacks to spray treatments in general is the great difficulty in providing a consistent effective barrier zone.
Generally in new home construction, barrier sprays are laid down in the soil prior to foundation slabs being laid which may be more effective than spraying existing structures. Unfortunately not every point of entry for a foraging termite colony is accessible to spray treatment in an existing home, and like a chain a barrier treatment is only as good as its weakest point.
Non-repellent sprays are designed to kill foragers and colony and are particularly effective against the subterranean form of the insect which nests in the ground surrounding a targeted building. Chemical termiticides that all under this classification include:
Non-repellent sprays are directly toxic to termites and are engineered to kill individual termites and to be carried back to the colony to lethal effect by returning foragers. They are therefore, slow acting termiticides that kill a colony via the concept of transfer—the poison being spread by the social interaction of the foraging termites with its nest mates, such as in feeding and grooming activities.
Each of the above non-repellent sprays has a different but equally deadly effect on termites coming into contact with them. Fipronil kills via transfer from one termite to the next during communal activities such as those described, and is particularly impervious to breakdown in the soil, which makes it advantageous for a long term barrier effect. Chlorfenapyr is a delayed toxic effect termiticide, not immediately lethal to the termite until it is broken down in the insect’s gut. Toxic metabolites of this chemical prevent the termite metabolism from producing energy, and this slow acting lethal effect allows for greater transfer throughout the colony. Imidocloprid is immediately lethal to termites encountering a full dose, but is unique in also being able to kill in smaller doses that are not immediately effective. Even a very small amount of imidocloprid causes a termite to become lethargic, unable to eat or feed other termites or groom itself. This inability to groom is the eventual cause of death—termites must constantly groom themselves and each other to avoid infestation by soil fungi which become parasitical feeders on the termite ogranisms.
How to Use a Termite Spray
While termite sprays are often marketed directly to consumers as “over the counter” treatment solution, the fact of the matter is that no openly available spray treatment on the consumer market is available in the strengths needed to deal most effectively with a termite colony. Professional pest control experts not only have access to otherwise restricted types and strengths of termiticides but also have specialized equipment that enables them to more effectively deploy the sprays where needed and in the concentrations required. It is advisable that homeowners leave the process to professionals whenever possible.
Whether applied professionally or by the homeowner themselves, it is necessary to know how to use a termite spray correctly.
The ideal termite spray treatment will take place under favorable weather conditions. The ground must not be frozen or wet; rainfall should not be expected soon after a treatment is conducted. Wind conditions must be precise—sprays cannot be effectively dispensed in windy conditions. Late spring and summer application is most common, and it is also when termites are most active in foraging.
In order to achieve a maximum concentration, it may be necessary to dig trenches along the edge of an existing structure’s foundation. Rods are then inserted in the spaces made by the trench, through which the termiticidal liquid will be injected. Where the trench and rod method is not feasible, extensive drilling into foundations and wall supports will be necessary. The key to any spray application method is in getting the barrier concentration of the chosen pesticidal agent correct. Anything less than the recommended application found on the product label will leave the treated structure vulnerable to termite foragers being able to take advantage of a gap in the treatment.
There are pros and cons to the use of liquid termite “spray” treatments, to summarize they are listed below:
• Provides immediate protection to structure
• When applied in uniform and correct concentrations are effective for years both on wood and in soil.
• Non-repellent termiticides minimize the “gaps” in treatment problem that exists with repellent treatments—the best spray application may be one that utilizes both.
• Relatively inexpensive when compared to other termite barrier methods including bait systems, and depending on the type of chemical chosen in the treatment.
• Achieving the perfect chemical barrier is difficult even under optimum conditions. This presents a particular problem when the barrier is repellent in intent—foraging termites will find the weakest link in a protective blanket and exploit it.
• The drilling that is necessary to adequately apply termite spray for wood into existing porches, supports, beams, subfloors can undermine structural integrity of the dwelling, even though the drill holes are filled and repaired by professional exterminators, they still represent an assault on the wood’s integrity and are often visible after treatment.
• Sprays introduced to a structure or property that is within 50 feet of a groundwater source present a risk of water contamination. Termite bating systems maybe a safer option in these areas.
The decision to spray treat termites is one that needs to be carefully considered and all options duly explored. The best termite treatment, both to eradicate existing colonies and prevent re-infestation, is generally one that is multi-pronged and overseen by a licensed and bonded extermination professional, of which termite spraying is but one tool in the anti-termite arsenal.