DE works by making microscopic cuts to the outside of the bed bug and the result is death via dehydration. As such it is a decent non chemical alternative in some insect settings. But does it work with the bed bug? One study showed that most bed bugs died within 4 days of continuous contact with DE and all died within 10 days. That is good information as far as it goes but there are a few practical problems associated with these facts.
Firstly, the study showed death occurred with continuous contact. How does one practically ensure that all harbourages are treated with DE? Given that bed bugs spend the vast majority of their time in harbourages that are difficult or impossible to access that is a very serious limitation. I suspect that the inability to put DE on all surfaces, cracks and crevices would ensure that most bed bugs would receive at best a 5% time exposure to DE. How well would DE work in that setting? There are no studies.
Also, the immature stages of the bed bug will molt their exoskeletons like a snake five times before they become mature. If DE cuts the exoskeleton of an immature bed bug they will simply create a new skin shortly thereafter anyways. As such, even in a perfect DE treated environment the bugs theoretically could simply shed their cut exoskeletons before death and the adult lay eggs before death and the cycle would repeat indefinitely.
As an exterminator who recognizes that the exterminator community does not have all the answers to the bed bug problem I am more than willing to try new ideas. I have attempted DE treatments combined with traditional chemical treatments and found it made no practical difference in the amount of time it took to get rid of the bugs. As such my large box of DE will become my lifetime supply of mostly unused product.
Now there is one place where DE really shines. Climb up interceptors require periodic cleaning and repowdering. If you repowder the interceptor with DE the bugs caught are confined to a DE treated surface and they will die quickly lessening the likelihood of escape or the ability of tenants to easily collect and misuse live bugs. This is a perfect, though small, application for DE.