
An effective method for killing aphids is to spray them with a pyrethroid insecticide such as resmethrin or permethrin. There are a number of pyrethroid based products available in most garden centers.
For full product descriptions of pyrethroid insecticides click here to get to the right section of Yardener's Tool Shed.
If you need a sprayer go to Hand Tools For Spraying also in the Tool Shed.