Yep kills good guys just like bad guys. That's why it has specific application guidelines and shouldn't be used indiscriminately.

Dave

Don, if you think through it, you'll know the answer to your own question. DE is absolutely a broad spectrum killer of arthropods. To make matters even worse, there are so many important beneficials in the soil, in our gardens, lawns, and in the environment that the collateral damage can be catastrophic.

In my opinion, DE should never be applied indiscriminately in the garden. I do use it in my garage, however, where black and brown widow spiders are fond of socializing and multiplying.

Out of curiosity, Don, have you been using DE?

DE doesn't kill badness. It kills bugs.

Don, are you still here? Have we been able to educate you and are you convinced? :-)

Diatomaceous earth is supposed to pierce the exoskeletons of insects, suck out the moisture, and dehydrate them—or something like that. Some people claim—and I don't know how true it is—that it can kill intestinal parasites (but if so, it would have another mode of action, since I'm pretty sure they don't have exoskeletons, and I don't think they're going to dehydrate inside a host; I guess some say the particles are sharp and this is somehow supposed to damage the parasites). It doesn't kill mammals or birds. I think the jury is still out on earthworms (but I'm pretty sure it would dry them up, even if it didn't pierce their skin—at least, if the DE was dry and it stuck to them). People use it to help keep their chickens worm-free. People use it to keep grain weevil-free in storage. Some people use it directly in the garden as a pesticide. Some people consume it in liquid for several alternative health purposes (the food grade kind—which is what you should be using in the garden)—although be aware that it has plenty of aluminum in it (so if you consume it in liquid, you may want to go easy on it; the food grade kind is generally regarded as safe—for humans—or GRAS). It's mostly amorphous silica, however. I use it to improve the taste of food, sometimes (when something I'm cooking tastes off, a dash of DE tends to make it taste better for some unknown reason). It is said to be used in some toothpaste. It can be used to keep things dry. It's an anti-caking agent. I used it to keep eggs from hatching, which had been hatching, on some squash seeds that I had once (I don't know what they were, but after I added the DE, I didn't see any more hatch). DE is made out of fossilized diatoms (which are creatures similar to plankton). It's used in dynamite (although I'm not sure what its purpose is there). You don't want to get it in your eyes. You don't want to inhale it. If it's not food grade, you really, really, really don't want to inhale it, eat it, or get it in your eyes—you might get cancer and kidney damage or something.

Speaking of wet DE, I'm not convinced that it does much to kill insects—or if it does, it takes a lot longer to do so than the dry stuff. Insects don't seem averse to wet DE.

I personally don't tend to think its use in the soil is going to lead to long-term damage to life. The particles are so small that they'll probably bind with something before they scratch up any insects (it's supposed to be able to chelate heavy metals and absorb toxins or some such; so, if true, I imagine it could chelate—or bind with—stuff in the soil, too), and the soil is likely to be moist if it has insects in it, anyway. It would probably be in small amounts in every particular location where a regular gardener might have it, in the end, which should further dilute the issue.

I could be wrong about that, though.

You're fine. Questions need to be asked.

Thanks again!