Insecticides For a Soil-Drench....Organic Remedies?

[BronxFatty]

Winter is approaching. Cooler weather here in Zone-7b New York City will soon force my fat-plant into quiescence/dormancy, BUT before bringing in my plants, I'd like to use some insecticide as a soil drench, to kill any and all pests before I bring the plants inside my home for the requisite long winter nap.

I would prefer to use some effective, but not highly toxic, or smelly, insecticide. Bonide (Imidacloprid) smells horrible....but I'll use it if I must to kill fungus gnats, root mealy bugs, etc. If there is an equally effective organic, homemade, drench, please let me know. Would some citrus peel concoction work? Murphy's Oil Soap? Pyrethrum, B-T granules? Neem oil?

I've read about this "SNS 203 Concentrated, All Natural Soil Drench", that Marijuana growers use pest-control on their weed crops. Never heard of it, never used it.

Drench will be used on Adeniums, Uncarina, Bursera, and some other caudex plants. Bonide is a systemic, and I read that it works.... but it's also toxic, and it smells really bad.

Many thanks for any suggestions? (I will apply the soil drench, BEFORE plants are brought into the house).