It’s clear that bed bugs have become a widespread problem in the United States once again, with reported incidences in all 50 states. The 2013 Bugs Without Borders Survey conducted by the National Pest Management Association (NPMA) and the University of Kentucky, and released in April of this year, found that bed bug infestations in the United States continue at high rates. In addition, bed bugs are still the most difficult pest to treat, according to 76 percent of survey respondents, more so than cockroaches, ants and termites.
Bed bugs are easily transported from place to place unknowingly by people, luggage, purses and used furniture. Recent research shows they also move between apartments and between homes in multi-family dwellings. Bed bugs are very cryptic, so people often don’t realize they have them until the infestation becomes very large, and by then, difficult to control.
According to Dr. Phil Koehler, professor of structural pest control and urban entomology at the University of Florida, a promising approach to managing the current bed bug pandemic is to prevent bed bug introductions from becoming full-blown infestations with multiple life stages.
The main method for preventing introductions from becoming infestations is to engage customers in a bed bug monitoring program to prevent introductions from getting out of hand. Yet, according to A Strategic Analysis of the U.S. Professional Turf and Ornamental Pesticide Market — The 2012 Season, only about one-third of pest management companies servicing accounts for bed bugs report employing monitoring devices as part of their service.
At NPMA PestWorld 2012, the National Pest Management Association’s annual conference and exposition, Koehler described several methods for detecting bed bugs and shared some ongoing research efforts aimed at finding more effective methods to treat them.
ENHANCED VISUAL INSPECTION. PestWest offers the Contrasting Specimen Inspection Kit (CSI), an enhanced visual inspection kit that includes specialty orange glasses and a 455 nm range blue-light lamp that are commonly used in the forensics industry to detect blood serum, which fluoresces. The blue-emitting light source is used to identify latent signs and other physical infestation evidence, while the orange glasses block the blue light so the examiner can see the fluorescence of the eggs and blood serum.
“Using this kit, the inspectors must know what they are looking for, but unfortunately a video camera does not capture much fluorescence, so there’s not a video for training purposes,” Koehler says. “As such, it takes a great deal of training to know what you are looking for in order to use these tools effectively.”
Recently introduced to the market, a Bed Bug Fecal Spot Detection Kit, from Bed Bug Blue, includes cotton swabs as well as developer tape and fluid. The inspector wipes the swab over the suspected fecal spot, and then applies it to the developer tape. After adding developer fluid, the spot on the tape will turn blue, indicating it is a fecal spot up to two years old.
According to Koehler, while the kit can confirm whether it is a bed bug fecal spot or not, it does not differentiate between active or old infestations.
DNA DETECTION. Research Associates Laboratory, and several other labs, offer an easy and effective method to detect bed bugs using their DNA. It is available to consumers as well as the pest control industry, so customers may have already sent in a sample for analysis prior to calling for an inspection. One simply swabs areas where bed bugs typically hide, completes an analysis request form and sends it in to the lab. Results are returned in about 24 hours and are 99 percent accurate.
Bed bug DNA detection can help determine where bed bugs have been and differentiate bed bugs from other insects and mites. However, it cannot help determine if treatment has been successful because their DNA remains active for more than one year.
BED BUG DOGS. Koehler says bed bug detection dogs make it much easier to identify bed bugs, provided that the dog has been trained and handled properly. Well trained and properly handled dogs can detect even small infestations and can distinguish between active infestations (live bugs and viable eggs) and evidence of past infestations such as dead bugs, feces and cast skins.
“At the University of Florida, we’ve tested dogs that have a defined training and handling regimen,” Koehler says. “And recent testing on the accuracy of bed bug sniffing dogs at the university shows that the dogs have a 98 percent accuracy rate and can differentiate between live bugs and dead bugs or past infestations.”
There are many canine schools that train dogs to detect bed bugs, but Koehler encourages companies to do a thorough investigation to ensure the dogs have been trained well and handled properly. NPMA has taken the lead to develop Best Management Practices for Bed Bugs, which include standards for canine bed bug detection team certification. NPMA’s Canine Detection Division also provides guidelines for selecting a trainer for an insect detection canine for pest management firms considering purchasing a canine for insect detection.
There are also several different forms of artificial bed bug sniffers on the market, such as the BBD-100 from TDS, although false alerts are a problem according to Koehler. \
“The gas has to be contained in order for it to work properly. If there’s a situation where there is a lot of air flow, it won’t be able to detect the bed bugs, even if there are hundreds of them next to the device,” Koehler says.
Another is called the Electronic Dog Nose Bed Bug Detective.
“I’ve always found it interesting that the Bed Bug Detective won the Popular Sciences 2011 Invention Award, but it has not been proven to work and the prototypes didn’t work very well,” says Koehler.
CARBON DIOXIDE FLUSH. Koehler also tested a carbon dioxide flush using a CO2 cartridge and a bicycle tire inflation regulator. Starved bed bugs responded immediately to the CO2 and they ran from harborages to the top of the bed. They introduced 100 bed bugs, gave them time to hide, and then turned on one of the cartridges. First, they tried to flush them out by spraying the CO2 into the cracks and crevices, but there was no response.
“We thought maybe the bed bugs didn’t want to come out for a host that is moving. The next time we set it down so it was a stationary CO2 source and they responded,” Koehler explains. “However, fed bed bugs won’t respond to a CO2 flush so it has its limitations. If someone had been sleeping in that bed, the bugs wouldn’t have responded the way they did.”
LEAVE-BEHIND DETECTORS. Of the leave-behind bed bug detectors, dual-action detectors are an effective means to trap the insects using the bed bug behavior theory that there are two types of bed bugs: host seeking and harborage seeking. Host-seeking bed bugs are attracted to CO2, kairomones, heat and color.
After feeding on the host, bed bugs then seek harborage using pheromones and their attraction to color, crack size and surface texture. Dual-action detectors utilize both “attraction to host” and “attraction to harborage” cues.
FMC manufactures the Verifi bed bug detector, a dual-action detector. The Verifi bed bug detector provides up to 90 days of active detection, at which point its attractants can be replaced and detection can continue. The Verifi bed bug detector creates a new ongoing bed bug service offering for pest management companies, while generating a recurring revenue stream. The detector is small, unobtrusive and easily installed on walls or behind furniture.
By continuing to detect bed bugs for up to 90 days, Verifi detects that an infestation is present, confirms that treatment was successful and provides ongoing detection to ensure that bed bugs are gone or to identify any new bed bugs that are introduced.
“During our research trials, the Verifi unit detected bed bugs in rooms where they were not obvious with a visual inspection,” Koehler says. “Verifi is a way for PMPs to identify infestations and increase their companies’ revenues by making treatments for infestations that would normally be overlooked. PMPs can also get paid for the monitoring itself, as opposed to just coming in and correcting a problem when it’s out of control.”
Preliminary data show that Verifi will activate bed bugs up to 5 feet away, but Koehler and his team are in the process of verifying that data. In addition, NPMA has given him a grant to study the activity of bed bugs over time and track individual bed bugs to see how much they move to help determine how many monitoring devices to place per room.
PROMISING NEW METHODS. Non-chemical treatments include using heat (e.g., a clothes drier or a heat chamber), a vacuum, mattress encasements and traps. An attractive non-chemical treatment is what Koehler calls the “Bed Bug Heat Box.” UF Associate Research Scientist, Roberto Pereira designed the process to work like a convection oven.
“He put all the infested furniture in the center of the room, and then created an oven around it using insulation boards. Inside the box, he placed two heaters and two fans so that the air is heated and circulated within the sealed box,” Koehler said. “It’s a very simple system to control bed bugs. It doesn’t require any use of pesticides, and the equipment that is used is fairly inexpensive.”
The goal was to get the temperature up to at least 120°F for at least one minute. All of the bed bugs died, even those under the mattress. The treatment also resulted in media coverage for the university. (Visit http://news.ufl.edu/2010/08/02/bed-bug-remedy/ to watch a video demonstration.)
Chemical treatments include sprays, dusts, insecticide vapors and fumigation, where appropriate. Dichlorvos (the active ingredient in Nuvan Prostrips) is still registered for bed bug control, but most treatments require an empty room or container, a minimum of seven days of treatment and at least two hours of aeration time.
“We decided to combine that process with heat in an effort to accelerate dichlorvos vaporization and shorten the time required to kill bed bugs and the eggs,” Koehler says.
They used vacant dorm rooms and placed a fan behind a heater to blow hot air on Nuvan Prostrips hanging from a stand. Using this procedure, the dichlorvos vaporized 60 times faster and bed bugs and eggs were killed more quickly — in one day vs. seven days.
“There are reasons why this worked well, but also some limitations,” says Koehler. “Heating strips is not prohibited on the label, but it’s not on the label as a treatment, per se. They are working on getting EPA-approved directions on the label, in conjunction with AMVAC.”
Currently, Koehler and Pereira are conducting research to determine use rates, equipment needed for heating and vapor circulation, timing for the most effective control and ventilation procedures to clear dichlorvos residues.
“Remember, these are only experiments. This research will be used to develop the new label directions for Nuvan plus heat treatments,” Koehler says. “Until a new label is developed, pest control operators should carefully follow the current label directions.”
The author is a contributing writer for PCT and can be contacted at firstname.lastname@example.org.