getting rid of cockroaches

don’t know how true this is, but i heard that cockroaches cannot stand chalk. Ordinary chalk that school teachers used to use when i was a nipper. Just draw a line around every opening where you think the roaches are coming from. They will not die straight away, ofcourse, but the chalk has the same effect on their “harnass” as the boric acid does. It eventually makes them “fall apart”.
Chalk will also discourage ants from crawling all over the place. They get confused when they reach a chalk line, and never cross it. They will always go around a line of chalk.

elfje

Hi and welcome to the SDMB! I’m assuming you’re referring to one of Cecil’s many columns on cockroaches, probably What’s the best way to kill cockroaches?

I don’t know about chalk, but diatomaceous earth will kill insects that crawl across it, and it’s non-toxic to larger animals (the linked site discusses feeding it to animals to control intestinal parasites).

I had understood that diatomaceous earth didn’t actually kill the creepy-crawlies, just irritate them? It gets in between the joints of their exoskeleton and itches.