in my experience when plants are afected by parasites, then there are other more fundamental problems. is the plant nourished enough? is the humidity/sunlight balance ideal? drafts? depleted soil?

if the plant is strong, it wont be much affected by a parasite, and can fend them off with its own tannins and other inherent pesticides.., with a little human help by squishing/picking off..

hope this helps,

Are you keeping the fig indoors or out? Pesticide sprays are a tricky subject on bonsai, the only one I use currently is Safer insecticidal soap, and that can cause problems if you use too much as well. Some people spray their trees whether they need them or not, some never use it at all, relying on regular spraying and picking off the culprits.

For scale I have just picked it off, my figs tend to be very picky though and drop their leaves at a moments notice so I probably wouldn't use anything harsh on them. Make sure it is getting plenty of air, spray it down with a jet from the hose regularly, (covering the soil when you wash off pests is a good idea) and pick off the scale. If all that doesn't work then you can try a mild insecticide.