Insect treatment of tropicals before bringing them in for the cold season

I have searched on this topic and did not find it previously addressed in the forums. Hope I am not bringing something up that is well-documented already.

I have been advised in the past to sprinkle a systemic insecticide on my tropical bonsai trees approximately a month before bringing them in for the cold season. This was put forth as a way to prevent infestation once the insects are separated from what keeps them in check outdoors. Well, I am almost to that time of year (growing zone 4 or 5, depending who you ask). A powder from Fertilome was recommended, the name of which escapes me. It seemed to work okay, but also seems to slow water drainage through the soil for a time. Alternately, I have sprayed neem oil (twice, about a week apart) on my plants when infestations have occurred. That's no fun in the house, and seems to suppress rather than eliminate the problem.

I have a variety of bonsai that I grow indoors- Fukien Tea, Brazilian Rain Tree, Eugenia Myrtifolia, Ficus, Schefflera, Crassula and Pachypodium- so I may not find a single solution for me, but what I am requesting is what others do regarding insects when they bring tropicals in for the cold months.

SAFER INSECTICIDAL SOAP

pretty easy to use and pretty benign stuff...

not a systemic, but it takes care of the problem once (and if) it shows up...

my ficus had the scales pretty bad when i first got it direct from florida and that took care of it....
important thing is 3 apps about 7-10 days apart which gets 'em in their various life cycles

i'm just kinda against using something for a problem that doesnt yet, and might not, exist.

Modern pesticides don't stick around to make winter-long preventative spraying (unless pests are actually present) very useful. Vigilance is required in winter, too.