The systemic pesticide I use is Bonide Systemic Houseplant Insect Control. Its active ingredient is disulfoton, an organophosphate.
The label says to use 2 rounded teaspoonsful per 6 inch pot. Mix into soil. Then water.
I find the conversion of these instructions from flower pots to bonsai pots something less than intuitive. For me, this translates into about a tablespoon and a half for a 16 inch pot, or an even dusting of the soil surface, which I then scratch into the upper level of soil.
It is my
opinion that the scratching into the soil and immediate watering, among other things, minimizes the risk that things (people, pets, etc.) will come in contact with this nasty stuff.
THIS IS A POISON ! TREAT IT WITH RESPECT! 
So far, I have only found it necessary to use this on ficus. Bougies, Texas Ebony, and jaboticaba have done fine without it (or I just can't see the critters
)