With the resurgence of the bedbug population in North America, the search for the “magic bullet” has never gotten so much attention. Though bedbugs’ heightened presence is commonly attributed to increased travel and the transfer of second hand furniture, the real concern for pest control operators is their apparent resistance to treatment.

In short, synthetic pyrethroid spray treatments seem to becoming less effective. This observation prompted Dr. Michael Potter of the University of Kentucky to study the issue of chemical resistance, and his hypothesis is that dust formulations may play an increasingly important role going forward. In his study, the results revealed that in even the most resistant bedbug population, more than 90 per cent of the bedbugs died within four days, with a 100 per cent kill rate after 10 days.

How dusts work
There are two main mechanisms by which dusts can desiccate insects. Like superfine sandpaper, certain dusts, including diatomaceous earth, kill principally by abrading the protective outer layer of wax on a bedbug as the insect crawls over or through the abrasive particles. Silica gels – for example, the little packet found in vitamin bottles to absorb moisture – are contained in Drione dust and function more like a sponge, absorbing the ultra thin lipid layer onto the particle matrix.

Dust versus spray products
One advantage of dusts is the residual effect of these products. Spray formulations are designed to breakdown fairly quickly where dusts can be effective for months. This is one of the reasons why at least two spray treatments are required to solve a bedbug infestation.

Dusts do not replace the use of sprays but are used to treat areas where sprays should not be used such as wall sockets and mattresses.

The safety of dusts is another reason why these products should be used. Both Drione and diatomaceous earth have a very permissive label and rate extremely low in toxicity to humans. In fact, they are much less toxic than commonly used household products.

What’s more, dusts have gone through rigorous testing and study, and have not only been approved for use by the federal government but recommended for use in the most crucial and sensitive areas.

Dan McCabe is vice-president at Magical Pest Control. He can be reached at dan@magicalpest.ca