Yellow sticky traps are effective controls when the insects begin to fly. Tiny black insects, fungus gnats hop around the surface of the soil. They're easily controlled with a soil drench of the bacterium Bt, or Bacillus thuringiensis . The larvae of fungus gnats are clear, threadlike worms with a black head. For better control, treat when the gnats are in their larval stage.
Scale insects resemble tiny turtle shells.
They're sucking insects as well and can be difficult to eliminate because their hard shells protect them well. Juvenile scale are much more vulnerable. Try applications of horticultural oil added to insecticidal soap to smother scale insects, or attempt to wipe them off plants manually with soapy water and a sponge. When spraying any type of insecticide, wear neoprene gloves and eye protection. Don't mix more spray than you can use at one time.