The fungi that cause damping off are oomycetes. Is this what you mean by "mold", Tracey?
Technically, molds are different animals, but they may or may not be oomycetes (I just don't know). Molds are usually what you find on old bread. Molds do not cause damping off.
I've never heard of cinnamon being used as an insecticide, although many of the herb oils might. I suspect people have gotten the two mixed up (fungicide and insecticide) and used them interchangeably. Then the "truism" gets spread around the internet, and as we all know, if it's on the internet it must be an infallible truth
