It's commonly believed that it's the abrasive sharp edges of DE particles piercing the exoskeleton of insects that gives DE its effectiveness, but UCLA research in the �70�s disproved that. It showed that DE's ability to absorb the insect�s waxy cuticle that's responsible for its effectiveness. When the water-proof outer layer of the insects 'skin' is compromised, rapid desiccation follows, causing eventual death. The result (dessication) is the same, it's just that the mechanism by which it occurs is usually misstated, and you can count me among the formerly misinformed.

So, you can see how a wet particles or particles that have already absorbed oils or other biocompounds that would reduce it's ability to further absorb anything would reduce its effectiveness. Also, all DE products and species of diatoms are not created equal in the insecticidal arena. As far as I know, no research has been done to try to identify the best/worst types of DE used as mechanical insecticides; so how your food grade product stacks up is beyond the limits of what I know.

Al

Yes, it cuts the bugs and they dry out and die.
It rained here quite heavily last night, so we'll see what happens. (also a test of the drainage in my pots)
I get almost all of my stuff natural/organic, so I really wasn't doing any looking around for specific DE. They had it (in bulk! cause they're awesome!) so that's what I got, and I trust it to be safe(er) than chemical nastiness.

Hope it works! also, the sun is back today, so hope my plants get some growing done. Probably need some more fertilizer...

Peg

Interesting info about the UCLA research on DE.

I've used DE to keep ants away from an outdoor cat feeding dish and noticed that it does not work if it has gotten wet. And it still won't work again after it dries out, so after a rain you might need to reapply it.

In a container, I've found it easier to just go out at night and pick off the pillbugs or whatever else was eating.

ahh, I think I *ahem* discovered what actually tore up one of my plants so badly. I pinched off the first buds that showed up, because the plant still had some growing to do. I think I might have pinched off parts of the surrounding leaves too, thus they've grown out looking like something took a huge bite out of them. Otherwise the others aren't too bad. i'll reapply it in a couple days (rain tomorrow too), but will also take a peek at night and see what's up.
I'll also use it if my ants come back (had to get some nastier ant killer a while ago and damn did it work!)
Thanks
Peg