For many years, the traditional method of controlling subterranean termites was to apply a liquid pesticide, known as a termiticide, to the soil. It has worked by applying a chemical barrier around and beneath the structure in order to block all possible routes of termite entry. Any termites attempting to penetrate through the treated soil were either killed or repelled.
However, there are many obstacles to forming such a barrier. Many possible termite entry points are hidden behind walls, floor coverings, and other obstructions.
Even here access for treatment is possible, it is difficult to uniformly wet soil and achieve thorough coverage. A typical "barrier" treatment may involve hundreds of gallons of solution injected into the ground alongside the foundation, beneath concrete slabs, and within foundation walls. Considering that termites can tunnel through small untreated gaps as narrow as pencil lead in the soil, it is understandable why the traditional/ barrier liquid treatments have failed to correct termite problems at times.
Most termiticides are not as stable in most soils as termiticides which were manufactured prior to 1989. Chloronated hydrocarbon insecticdes (termiticdes) like chlordane, aldrin, lindane, etc. were known to have tremendous stability in soils and lasted a lot longer than the present termiticides.
The same qualities which made them good termiticides also made them environmentally unsafe. Chlordane got the bad reputation from wide misuse and was taken off the market in the USA.
There are several different insecticides used by pest control operators for soil treatment for termites currently. All are safe and effective when used according to label directions. The insecticides remain effective in the soil for approximately 5 to 10 years. Each product has slight advantages and disadvantages.
Effective termite treatments require a great volume of termiticide. For example, a single-story house that is 1200 sq. ft. (40' x 30') can require 112 gallons of diluted termiticide just to treat the soil along the foundation walls (inside and out). The total gallons needed may exceed 150 gallons depending upon the construction of the house.
Termites "Bite" into Pocketbook by Barb Ogg, PhD, Extension Educator, Lancaster County Extension Office and Dennis Ferraro, Extension Educator, Douglas County Extension Office, talks about the amount of termiticide needed to do the job correctly.
The physical and chemical nature of your soil surrounding your home can impact the effectiveness of the chemicals stability with respect to time. Soil clay content, pH, Organic matter content, particularly organic carbon content will greatly influence the rate of break down of the termiticide in soil.
You can consult your local land grant-extension entomologist to evaluate your soil. Soil samples can be inexpensive, some may be free, allowing you a more informed choice.
Baiting for termites, although generally more expensive, may be a better alternative.
For an excellent article: Fate
of Insecticides Used for Termite Control in Soil, by Shripat T. Kamble
Extension Specialist, Univ. of Nebraska,covers the different soil conditions
affecting current termiticides.
1. Pre Treatment for Pre Construciton of Structures
Homes and other buildings can be pretreated at the time of construction to protect them against termite attack.
After the footings are poured and the foundational walls and /or piers have been constructed, apply the termiticide such as Taurus SC to a trench in the soil about 12 inches wide and 6 inches deep adjacent to the foundation.
Soil on both sides of the exposed foundational walls and soil surrounding should be soaked down to the foundation footing at the labelled rate.
Apply at the diluted rate. Poured in with a watering can or bucket is easier than using a sprayer.
No need to dig the trench any deeper than the top of the footing.
Soil at the bottom of the trench can be loosened with a spade or iron bar to allow further penetration.
For outside basement walls(where the footing is deep) most pest control operators apply the chemical by injecting it along the foundation through a hollow rod attached at the end of the hose in place of a soil nozzle. This is called "rodding". The result is a continuous chemical barrier from footing to surface.
This should be applied to both the inside and outside of the foundation and also around piers, chimney bases,pipes,conduits,and other structures in contact to the soil.
Use at the rate of 4 gallons per 10 linear feet. The diluted termiticide should be mixed in with the soil, as it replaced.
With Floating slabs the foundation wall rests on a poured concrete footing.
The slab is poured after the foundation has been completed.
With Monolithic slabs,
the footing and the slab are all one piece of concrete.
Suspended slabs rest on the foundation wall.
These are supported on the edges.
For effective pretreatment termite proofing, much of the chemical barrier needs to put under the concrete slabs. Obviously it is easier to put out the barrier treatment BEFORE a slab has been poured. AFTER it has been poured, it will need to be drilled and a chemical injected under the slab to seal off termite entry points. This may not a "do it yourself project".
Apply a diluted termiticide such as Taurus SC at the rate of 1 gallon per 10 sq. feet, covering the square footage.
Along both sides of the foundational walls and interior foundational walls and plumbing, apply this diluted rate at the rate of 4 gallons per 10 linear feet.
Outside Barrier/Permiter Treatment:
Dig narrow trenches along both the inside and outside of foundation walls and around piers and chimney bases,applied at the rate of 4 gal. per 10 linear feet.
Also be sure to trench and treat around sewer pipes, conduits and all other structural members in contact with the soil.
The trench should be as deep as the top of the footing.
Mix the termiticide with the soil as it is replaced.
The State regulations differ state to state on treatment and drilling activity required.
Changing the soil along the foundation such as digging or removal of treated soil can encourage termites to your home.
Disturbing the termite treatment may void any termite warranty that you may have on your home.
An excellent article about renovations and home construction by Michael
Waldvogel, North Carolina Entomology Extension Specialist, can be found
Treating the wood is an alternative to soil treatments.
However, it must be emphasized that these "spot" treatments on the wood is not a complete termite treatment in that it will not stop the termites from attacking the wood in other areas.
Both products are borax based and must be applied to untreated wood . Important areas for treatments could be in the crawlspace and parts of the framing in a house under construction.
Data provided by product manufacturers indicate that termites do not extend their tubes over treated wood nor do they cause any structural damage.