New research suggests that essential oils can be used as insectersides. Rosemary, Thyme, Clove and Mint have been proven to deter pests in the garden and on the farm. As they're only plant extracts they don't need to be approved by the the appropriate governing bodies and are suitable for organic growers.
These killer spices are usually used in a combination of two or four spices, some pests are deterred by the spices and others irradicated. Also pests are less likely to build up resistance to the spices than they are to conventional insectacides. At present they only have a small amount of the market share but it's growing. Usually these insectacides are a mixture of the plant extract and water - that's it so you could make your own at home, just remember to shake before use as the oil and water will seperate when left for a while.
The only downsides are they need to be applied more often than regular pestacides and are less potent so more needs to be applied.