How Do Floods Affect Termite Treatments?

Paul Hardy, a 55-year industry professional and current consultant, examines how termite customers can be impacted by flooding or moving water.

Editor’s note: The following article was written by Paul Hardy, a consultant with more than 55 years of pest control industry experience. Hardy is owner of JP Hardy Consulting, which offers consulting services to small and large pest control companies on a variety of technical and training issues. Contact Hardy at or

I have received a lot of calls and emails from pest management professionals in affected areas concerning flooding from hurricanes and other unusual weather conditions. The question I receive is: “What about our termite customers in areas that have been flooded and experienced standing or moving water?”

To answer that question, you have to look at how termite work in the aftermath of floods differs from year’s past. Ever since 1995-1996, the industry as a whole has been controlling termites differently. In 1995, many PMPs started using baits as their primary treatment method. Later, in 1996, we were reintroduced to non-repellent termiticides.

The first non-repellent termiticide that we used was chlordane. Most of us did not know that chlordane was non-repellent and what that would mean for termite control. Termiticides are not all created equal. Some may reach to water-chlorinated hydrocarbons attached to soil very tightly and would last for a long time without soil disturbance or movement. Organophosphates also have shown to remain in the soil for more than 35 years at some USDA test sites in Gulfport, Miss. Pyrethriods, as a general category of termiticides, also attach very well to organic matter and soil, lasting for many years. Bifenthrin may be the longest lasting, with more than 26 years of soil testing.

The unknown is newer termiticides, which have undergone 21 years of soil testing at USDA sites. The problem is that newer termiticides, by design, were made not to last in the different soil types as long as older termiticides. Some of them are showing residuals that may be as long as chlordane, which will be the next problem in the environment.

Most termiticides are stable when applied to soil and the soil is allowed to dry. In order for that termiticide to be removed from a particle of sand, the termiticides would have to be subjected to a solvent or some type of chemical that would cause the termiticide to move. Normal rains with no soil movement do not create a problem. With flooding and heavy rains, the problem is soil movement, not water. Soil erosion may cause soil to move away, move against, or cover up the foundation walls and treated vertical zone. Standing water can create other problems, such as rot, decay, fungus, and mold. Moving water brings with it sand, debris, silt, and oils from roads, driveways, and drain systems. These can build up around structures covering the treated zones. Baits are another story. With stand-alone bait programs there is no treated barrier or treated zone as there is with non-repellent liquid termiticides. Baits have completed 20 years of field usage and when serviced properly, have equal results as liquid treatments.

Flooding can bring all kinds of debris and deposit it on top of the monitors and bait stations. This can make it hard to locate the stations. Standing water can affect the baits that are in the stations and can cause decay and mold to form on the monitor material. Past studies have shown that standing water for several days can greatly reduce the subterranean termite colony size and colony redevelopment can take several years. Downed trees and tree limbs need to be inspected for Formosan termites if in a Formosan termite area before they are discarded in order to prevent spreading of infestations to other areas.

There is no one answer on what to do following a hurricane or flood. Each situation can be very different. At the very least, every structure in the affected area should be inspected and a record made of the conditions as a result of the storm. Digital pictures are a great tool to record what was discovered at the time of the inspection.

Needed treatments should be scheduled to be done after needed repairs are made on the structure and the landscape is stabilized. Applying termiticides and installing bait systems prior to the structure being repaired and the landscape being completed only results in additional work. Soil should be dry and back to normal condition before treatment and installation of bait systems is completed. Remember, soil is considered dry when you cannot squeeze water out of it with your hands.

Bait systems that have been covered with water for any length of time may need replaced. Baits in the ground should be replaced with a monitor. If the station was covered with debris that may have contained slugs, the station may need to be replaced. Monitors may also need to be replaced. Missing stations that cannot be located need to be replaced in accordance to the last inspection monitoring report. Based on past floods and standing water problems, it does not kill all termites. At best, it only slows them down for a while and they later return with a vengeance, especially the Formosan termites. All the more reason why we need to contact customers and make sure their termite protection is in place. Frequent inspection is the key to termite control success. Elimination is not possible regardless of claims. 

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