Funny you should ask that,
@dragnlaw - someone on a garden forum asked me some questions about the Surround, which I answered for her.
I buy it at Peaceful Valley Farm, because have 25 lb bags (this lasts me 5 or 6 years), and they offer a flat rate shipping, though I have no idea what shipping to Canada would cost. Most places charge more for the shipping than the item, for things like this!
Derived from kaolin clay, a natural mineral, Surround WP is labeled to control insect pests and disease, while protecting against sunburn and heat stress.
www.groworganic.com
I use about 2 c of surround/gal for the first sprays. And I do add some potassium bicarbonate to the mix, as a prophylactic - about 1½ tb/gal. And what I do is take a fine strainer, about 3" in diameter, and put the KHCO3 in it first, then put a half cup of Surround in on top, and take the hose fitting on "shower", and wash it through the strainer through the top of the sprayer. I then add more Surround in, using the same method, adding a half cup at a time, until I have 4 cups in, for the 2 gal sprayer. This breaks up the particles, so the sprayer won't clog up, while spraying.
I then add a tsp of the spreader/sticker ThermX70; I don't know how adding oils would affect it, but we know it quickly becomes too hot to be applying oils, so I usually don't mix these.
Later in the season, I reduce the amount to 1½ c/gal, partly because I am often re-spraying, after heavy rains, and there is still some on them. And as soon as the cherry tomatoes begin setting fruits, I stop spraying those, as it is a pain trying to get the Surround off of those small fruits - it doesn't just rinse off, like DE, or sand. Large tomatoes, eggplants, and other larger vegetables wipe clean easily, but not small peppers and tomatoes, or irregular surfaces on some vegetables.
The Surround works well against flea beetles, as well as other beetles, and aphids. Unfortunately, it doesn't seem to affect those spotted lanternflies, that are becoming more of a pest around here every year.
I just saw 2 more set fruits on those Oaxacan Jewels this morning! I'll buzz some more blossoms when I go back out, to set them faster - other varieties should be setting soon.