The package directions (it's marketed for succulents, which are a huge market here, I suppose like houseplants became popular during the pandemic) actually suggested mixing it with
water and spraying on.
Miraculously, it looks like we have 5 days with a low chance of rain, so I did a test yesterday directly on known infestations: a pigeon
pea bush that's got some scale bugs with ant farmers, some eggplant that got attacked by flea beetles, and the tomatillos, which I remember as being so resistant to everything but lately are attracting so many bugs that my daughter the insect biologist has been spending a lot of time picking "weirdos" off it to bring to the lab.
We'll see what happens over the next few days.