[Bed Bugs] Freeze

Cigarette beetles and bed bugs: these are the two insects that led Terminix and me to the "cold side" of the pest control industry. In November 2005, we approached a large manufacturer with an entirely new way of tackling a large cigarette beetle (Lasioderma serricone) infestation. The idea at the time was to use liquid carbon dioxide (CO2) converted into a dry ice "snow" to rapidly freeze the beetles, while not harming the manufactured product or bringing production to a complete standstill. This method was accomplished with the use of a device manufactured by CTS Technologies utilizing the Cryonite technology. Terminix re-branded and marketed it as RapidFreeze.

What is RapidFreeze? Technically, RapidFreeze is a non-pesticidal device that converts liquid CO2 into specific particle sizes of dry ice snow. As this "snow" evaporates, bed bugs and their eggs are killed. Similarly, stored product pests and smaller cockroaches that come into contact with the snow are killed.

The RapidFreeze unit draws carbon dioxide from a 20-pound cylinder (equipped with a siphon or dip tube) to create the dry ice snow. Tanks are available at most gas companies and typically cost $25 per tank. It’s been our experience that the average 20-pound tank will treat about two average-sized, bed bug-infested hotel rooms.

The first time I heard about Cryonite technology, the term "snow" was used quite liberally to describe how the product worked. And as a national account manager in charge of food-processing clients, my first thought was "flour + snow = big mess." In reality, however, "snow" is merely what the particles resemble as they shoot out of the nozzle at -80°C. To be most effective, the layer of snow over the insect needs to evaporate within 30 seconds, thereby creating maximum heat transfer from the insect’s cells, causing them to freeze and the insect to die. The snow is dry and leaves no mess or stains, and, when used as directed, may safely be used on most surfaces. The snow penetrates cracks and crevices, killing insects it contacts and flushing others from harborages. Since the snow is non-toxic, the product can be used in hospital rooms, nursing homes, day-care centers, etc.

Since the snow is completely dry, it possesses some unique advantages when treating stored product pests, as no residual material is left behind. For instance, when we treated a bakery for red flour beetles (Tribolium castaneum) it was possible to treat the machinery in the mill without having to stop production since we didn’t run the risk of electrocution. Additionally, since the snow penetrates cracks and crevices, it was able to flush out those pests not killed initially by the treatment so they could be vacuumed. We had looked at the device as a method of killing insects but had not considered the side benefit of its ability to penetrate hard-to-reach areas. It was this discovery that led Terminix to examine RapidFreeze as a technique against bed bugs.

During the time we were initially testing RapidFreeze, bed bugs were making a strong comeback in the United States. While looking for other ways to use the RapidFreeze unit and to differentiate ourselves from the competition, we received a call from a customer looking for an organic, odorless solution to her bed bug problem. After consulting with several testing labs on RapidFreeze’s ability to kill bed bugs, Terminix designed a protocol around the RapidFreeze unit, combining it with vacuuming and residual treatments. This protocol became an important bed bug strategy for Terminix.

How does it work? Since the RapidFreeze snow comes out at -80°C, the effect is nearly instantaneous. At this temperature, the insect cannot compensate for the rapid change in temperature and cellular disruption that occurs. However, this method does not always kill the insect instantly. The larger the insect’s mass, the longer the effect necessary to kill it. Since insects have various physiological protection mechanisms to survive low temperatures, the key has been to overcome their natural defenses against freezing.

I prove this to kids by putting June bugs (Cotinis nitida) in the freezer to slow them down so that we can tie thread around their legs. Ten minutes in the freezer buys us about five minutes in 90-degree heat. With RapidFreeze, the effect is so fast that the insect is not able to lower its freezing point by producing antifreeze agents such as sugar, alcohol and proteins because the temperature decrease is so sharp. The faster the temperature drops, the better.

This rapid decrease in temperature is catalyzed by the size of the particle of each piece of snow. Consider the CO2 in a fire extinguisher. Those particles are much larger in order to reach the fire. A large particle size for killing bed bugs, however, would be ineffective since it could potentially create an "igloo" effect, thereby generating space between the snow and the insect’s body. Enough insulating air could be trapped to allow the insect to survive. The particles in the RapidFreeze machine come out much smaller.

Other treatment options. Various methods and protocols in our industry exist regarding the treatment of bed bugs. The most common three protocols are (in no particular order): steam, heat and freezing. Each approach has merits and limitations that warrant further explanation.

Steam. When using steam, it is important to remember that it can only be used in certain areas of a room, and in such cases, only a small portion of the steam will reach the intended target. Most of the steam will condense upon hitting the cool surfaces. So if you are treating a deep crevice or a thick mattress or box spring, the amount of heat energy eventually hitting any bed bugs may not be enough to kill them or their eggs. Another important issue to consider when treating mattresses with steam is the mold factor.

As the moisture collects, mold can develop, thereby possibly damaging the mattress. Steam also cannot be used on cracks and crevices in wooden furniture, picture frames, books and electronics that could be damaged by excess moisture or heat.

Heat. Heat treatments are increasingly being examined as a bed bug strategy. The biggest challenge with heat, however, is reaching the target temperature in deeply hidden cracks and voids where bed bugs could be hiding. Bed bugs are mobile creatures and can seek out microenvironments nearby where the heat may not rise high enough to kill them. Heat treatments, therefore, require a certain level of skill and experience to manipulate target temperatures into all harborages where bed bugs could be hiding. This treatment process is also time-intensive.

Heated air needs to be well circulated, and bed bugs are often well contained, either by caulking or applying insecticide dust prior to the treatment. Heat-sensitive items such as electronics and plastics must be protected with thermal blankets or removed from the treatment area altogether. But some items, such as vinyl windows and plastic parts of big appliances, are difficult to protect or remove and may suffer damage. Depending on the temperature and the duration of the treatment, wood furniture might shrink or crack due to rapid loss of moisture. And since not every item is heated, some bed bugs might escape, especially if the target temperature is not reached in those sites or the bugs are in items removed or covered.

Heating equipment setups can be expensive but heat is used by many companies to kill bed bugs in furniture, mattresses and other items when these are placed in a chamber designed for heat treatment.

Freezing. The main benefit of using RapidFreeze instead of steam or heat is its versatility. According to the manufacturer, it can be used safely in nearly every location bed bugs can hide. Smoke detectors, sprinkler systems and hot light bulbs, however, represent the three sites where RapidFreeze cannot be used; otherwise, it can be used on nearly every surface or area in a home, including computers and electronics, books, video tapes, DVD cases and similar items. If used correctly, RapidFreeze does not damage furniture or bedding and the treatment is organic and non-toxic. Additionally, migration by bed bugs to other areas is decreased when RapidFreeze is used in combination with vacuuming and residual treatments. And most importantly, the device is easily transported and inexpensive to operate.

RapidFreeze has proven effective in the treatment of bed bugs or their eggs on most any surface and has proven highly efficient at chasing bugs from harborages where they can be vacuumed or killed using the dry ice snow. One main drawback with RapidFreeze is that it must directly contact the insect or eggs to work; therefore, application into voids may not always reach all bugs hiding within. As with any technique, some skill is necessary for maximum effectiveness. By itself, however, RapidFreeze is not a panacea against bed bugs or other pests. Multiple techniques and strategies are necessary for best results. It is a tool that bears examination by PMPs offering bed bug services, weighing its advantages and limitations against other strategies and methods as discussed previously.

The author is national accounts manager for Terminix International. He can be reached at
jdrain@giemedia.com.