Tips for Improving Termiticide Applications

Soil applications for termiticides are used to prevent entry of termites into a structure. A continuous non-uniform barrier should not generate callbacks for years, until "thin" parts of the barrier have degraded and termites get through. As many PCOs know, non-continuous barriers can generate callbacks right away since untreated areas already exist.

The following termiticide application information was obtained from discussions with pest control companies that have performed thousands of treatments with callback rates of 5 percent or less, recent FMC Pest Control Specialties in-house research and from published literature.

PCOs interested in improving their callback rates should be aware of the following termiticide application information:

• Soil will only soak up termiticide at a given rate and no faster. Dry soil soaks faster than moist soil. Frozen or water-saturated soil cannot accept termiticide. Sand soaks faster than clay. Loose sand soaks faster than packed sand. Certain soils soak well for a while, then swell and much more time is required for continuous soaking.

Applying termiticide at a faster rate than the soil can absorb it results in random run-off of termiticide and a poor barrier. This is why holes drilled through cement must not be greater than 12 inches apart, and the termiticide should be injected at no faster than 1 gallon per minute (for most soils). If this application rate is too slow for your business (i.e., you have a short time allowed for a particular treatment), use the slow flow rate for callbacks when you usually treat fewer holes.

• Soil cannot be pressurized. Increases in pressure allow for faster delivery of more termiticide volume, but results in random run-off and the boring holes in the ground ("gold mining technique"), producing a poor barrier. This is why trenching is required for all applications not made through concrete, and why rodding holes through a trench must be spaced in the 4 to 6-inch range so that treated soil columns will connect with each other.

• The penetration of termiticides and water do not occur to the same depth in the soil. This mans that if you dig a trench 6 inches deep by 6 inches wide (at top), and fill 10 linear feet of it full of termiticide (9.4 gallons), most of he termiticide will be nearer the surface and probably very little of it will penetrate 2 feet down, even if the water penetrates down 2 feet. Termiticides attach quickly to soil and the deeper you sample, the less termiticide you will find. It is also why soil rods are used to establish barriers deeper than about 6 inches.

• Inject block walls (when you do) no higher than the third course of blacks from the floor. Research has shown that labeled termiticide volumes (dyed water) will not reach the footing if the injection is higher than the third course of blocks (and dyed water moves further than termiticides). Remember to inject all voids in the block walls, and keep in mind that block voids may be filled with concrete or beer cans, preventing thorough treatment.

• Termites cannot pick up and move soil treated with permethrin. If the permethrin (active ingredient in Dragnet FT) soil concentration is no lower than about 1 part per million (ppm), the termite barrier is satisfactory (kills or repels termites, depending upon ppm in soil). The degradation rate of permethrin is also slow enough to yield termite control for many years even if the initial barrier was weak.

• If you have a callback, the termites got around the treatment somehow. You need to consider how this happened. Is the treatment old enough for thin barriers to have degraded allowing termites through (less than 1 ppm)? Was this a treatment performed without trenching or at to fast an application rate? Could the termites have tubed over the treatment on the underside of he slab or through a soil crack? Was too little termiticide volume applied? There is a direct relationship between low termiticide volume and high callback rates.

When you have termiticide application problems, try a new approach, redrill other areas, use backward application nozzles to treat the underside of concrete, try three or four nozzle tips, or consider using a slower injection rate.

For more information about proper termiticide applications, contact FMCCorp., Pest Control Specialties Operations, Box 8, Princeton, N.J. 08543 or call 800/321-1FMC.

 

Dr. James Ballard is the national technical manager for FMC Pest Control Specialties Operations, based in Princeton, N.J.

REFERENCES:

Bull. Environ. Contam. Toxic 190. 5:422-428.

FMC Project 38-NJ-1989.

FMC Tech Update #4, September 1990. Econ. Entomol. 1968. 61:380-383.

Pest Control Technology (1988, 16:33,34,36), (1989, 17:70,74,76,77), (1990, 18:64,66).

Pest Control (1957, 25:32,33,34,50), (1990, 58:36,38,40), (1990, 58:24,30,34,36).

 

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