Bed Bugs, Turning Up the Heat

August 21, 2009

PESTICIDE RESISTANCE and bedbugs’ innate ability to avoid toxicant contact by hiding in cracks and crevices during daylight hours make alternatives like traps and heat hot topics at Entomological Society of America annual meetings. In contrast to ticks, where researchers have at least investigated biocontrols like micro-wasps, insect-killing nematodes and fungi, bedbug natural enemies have mostly escaped scientific scrutiny and testing.

Rutgers University’s Changlu Wang, an IPM (Integrated Pest Management; using multiple techniques) expert, is better known for his cockroach trapping skills in large public housing and apartment complexes in Indiana. Against bedbugs, Wang uses natural diatomaceous earth in bedbug interceptor traps (Climbup(TM); Susan McKnight, Inc.). This is in addition to clutter removal, bagging and washing infested belongings, new encased mattresses, and steam treatment (vaporized hot water) of floors, drapes and sofas.

Interceptor traps are designed to monitor bedbug infestations, and provide researchers population data. But these bedpost traps are also good control tools: In 10 weeks capturing 50% of the 8 to 1,103 bedbugs per one-bedroom apartment in Indiana. Though bedbugs can still crawl up from walls or behind headboards if a bed is flush against them, or even drop from ceilings.

Unlike “moat” traps surrounding bedposts, interceptor traps have a small container (which Wang fills with 20 ml of antifreeze for insect collection) inside of a larger container that Wang fills with an insecticidal formulation of diatomaceous earth. Future bedbug traps may also be able to take advantage of recently discovered airborne bedbug aggregation pheromones.

At the University of Florida Institute of Food and Agricultural Sciences, Roberto Pereira and others are working on heat fumigation to kill bedbugs. When test tubes containing bedbugs are placed in 111-113 F (44-45 C) hot tubs, these hardy insects survive an amazing 2 to 6 hours.

However, specialized pest control companies in the southern California counties of San Diego and Orange routinely use heat (hot air) fumigation instead of chemical pesticides against drywood termites embedded deep in wooden structures. It requires skill to arrange fans to circulate hot air in buildings. Temperature readings inside the wood are needed every half hour or so to calculate the heat dose needed to cook the insects. If it can be done economically with termites living in walls, heat fumigation can also be done with bedbugs. But expect stiff resistance to heat technologies from established companies with large fixed investments in traditional chemical fumigation skills and equipment.

A cheaper alternative to whole room or whole building heat fumigation is relatively low-cost portable heat chambers. Small heat chambers (e.g. constructed of foam boards) costing $400 or less are already used by the hotel industry, shelters and others to disinfest furnishings. In Florida, portable heat chambers stop the annual spread of bedbugs on preowned beds and furnishings purchased by students. Hospitals have used heat to disinfest wheelchairs of patients too sensitive for pesticide treatments.

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