She may have been thinking also about dia....... uhm diatoma........ diatomaceous earth.
from Wikipedia
Pest control
Diatomite is also used as an insecticide, due to its physico-sorptive properties. The fine powder absorbs lipids from the waxy outer layer of insects' exoskeletons, causing them to dehydrate[7]. Arthropods die as a result of the water pressure deficiency, based on Fick's law of diffusion. This also works against gastropods and is commonly employed in gardening to defeat slugs. However, since slugs inhabit humid environments, efficacy is very low. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Medical-grade diatomite is sometimes used to de-worm both animals and humans. It is most commonly used in lieu of boric acid, and can be used to help control and eventually eliminate a cockroach infestation. This material has wide application for insect control in grain storage.[8