This is a solution of special soap mixed with oil and water that can be used to control aphids and other soft-bodied insects. It's virtually nontoxic and leaves no residue in the soil. BT kills caterpillars and a variety of other worms. It's considered harmless to noncaterpillar critters, humans and other mammals. This chemical has more power than most synthetic chemicals, and it kills a substantial variety of insects.
Pyrethrum is available in dust or spray forms.
This new insecticide comes from the tropical neem tree. Unlike pyrethrum, it has a very low toxicity level but works well for crickets, cockroaches, beetles and leaf miners. They're light, can be applied year-round and control a variety of pests and certain fungal diseases. Oils are not highly toxic but may cause skin and eye irritation in sensitive individuals. So cover exposed skin when using insecticides, and don't spray or dust when winds are active.