Soapy water sprays can be quite effective against aphids and spider mites. When using any of these sprays, wet both sides of the leaves and repeat after a rain or as often as necessary. Flour and salt can also be used to repel pests. Use them as a dust to suffocate or dehydrate many kinds of caterpillars. Wood ashes sprinkled around the base of plants discourages cutworm attack.
Most natural insecticides are less toxic than synthetic chemical controls.
They don't accumulate in the environment or in animal tissues, and most insects don't readily develop a resistance to them. Still, they can upset the natural balance in your garden because some of them will kill beneficial insects and honeybees. Be aware of any specific toxicities indicated on the label and spray late in the day when bees have returned to their hives. Always wear a mask and remove contact lenses when applying dusts or powders. You should wear gloves and protective clothing when applying any type of pesticide.