Jeffrey Hahn, University of Minnesota Asst. Extension Entomologist
In the fight against bed bugs, one of the challenges is knowing whether these biting insects are present and where they are located in a building. Recent research at Rutgers has developed a monitor that will make it easier to find them. This research was presented at the 2009 Entomological Society of America (ESA) annual meetings held in Indianapolis and has since been widely reported in the media.
This research, conducted by Wan-Tien Tsai and Changlu Wang, found that a monitor could be successfully made from an insulated plastic 1/3 gallon jug filled with about 2 ½ pounds of dry ice pellets. You leave the pour spout partially open to allow CO2to escape which emits CO2 for about 11 hours. The jug is set on top of an upside pet food dish. Put fabric around the outside of the dish to allow bed bugs easy access to the inner part of the dish. You should also coat the inner section of the dish with talcum powder so the bed bugs can not climb back out. This trap costs about $15.
While this monitor has been demonstrated to be effective in detecting bed bugs, some members of the media have misconstrued this technique as a cheap method for controlling bed bugs. This monitor WILL NOT CONTROL AND ELIMINATE bed bugs in your home. Further, there are apparently some reports of pest control services (although none I am aware of in Minnesota) that have been using this monitor incorrectly in bed bug control programs.
Again, these monitors are to be used to determine whether bed bugs are present in your home. People that are suffering unknown bites but have not seen any insects could verify whether bed bugs are present or not with this monitor. For people that have bed bugs treated in their home, this trap can be used to help determine whether any bed bugs still remain.
With that said, there are some drawbacks to this monitor and people should consider carefully whether they wish to use it. First, while the components to build this trap are inexpensive, dry ice may not be easily obtained. People need to exercise caution when handling dry ice. You should never touch dry ice directly or allow it to contact bare skin as this will cause freeze burns. You can not store dry ice, not even in your freezer. You have less than a day to use it before it evaporates.
This monitor is also a potential child hazard. The trap is unsecured and a curious child could open the jug and accidentally touch the dry ice and severely injure themselves. It is even possible that if more dry ice is used than is suggested and the trap is placed in a small room with poor ventilation that the CO2 could be very harmful to people in that room.
This monitor is an advancement in the war on bed bugs but people that are considering whether to make one themselves at home need to understand its safe and use and limitations. For more information on bed bug monitors, including dry ice traps, see the Rutgers Cooperative Extension fact sheet, http://njaes.rutgers.edu/pubs/publication.asp?pid=FS1117