system
Given the following post, respond as if you're commenting on Reddit:
human
Diatomaceous Earth. How does it actually function as an insecticide?

I keep seeing that it works via a mechanical action, by abrading the joints of insects, or all sorts of other "cool" analogies about working like "broken glass" on insects, but I suspect it is more of a dessicant. If it IS a dessicant, wouldn't corn starch or other dessicants work as well?
gpt
The abrasion model is correct. Put some under a microscope and check it out for yourself. It is made up of the exoskeletton of diatom frustules, which are quite angular, sharp and made of silica (essentially glass). As such, it is chemically inert from an insects point of view.

It is not a dessicant as it remains effective even in rainy conditions, which would definitely not be the case for soaked corn starch.