Divide and repot any tropicals you have outdoors to prepare them for their winter home. Hose off or wash plants with soapy water and inspect them for insects. If needed, treat them with an appropriate insecticide. Imidacloprid, the active ingredient in many of the new insecticides, is a good systemic for insect control. It can be mixed with water and poured on the soil. The plant will take it up.