Organic insecticides are a prime need for those who are into organic farming. In organic farming, you depend on your farming methods to ensure that your plants do not have pests, but even when there are pests, you can learn to ignore some of them as long as they are not enough to cause damage to your plants. However, when you reach a stage whereby you need to get rid of your pests, you need to use organic insecticides to get rid of these pests.
Organic insecticides are thought to be environmentally sound, causing no harm to the earth, humans, or animals. They often consist of such things as fatty acids and plant oils. Natural pesticides act upon pests either through contact, or through absorption by the pests of these chemicals. The advantage of using organic pesticides is more of a reverse strategy, whereby you consider that artificial pesticides can use harmful chemicals (DDT anyone?), with a lot of residue left behind that affects other insects and pollutes through run-offs into rivers and streams.
However, you should keep in mind that using pesticides is part of an overall pest avoidance strategy that employs the usage of traps, and naturally occurring insects / other animals which counter the pests. This is also because artificial insecticides are more powerful than organic ones, and you need to compensate with a more comprehensive pest avoidance strategy. You need to ensure that you are following all these tactics before you start considering the use of pesticides (even organic pesticides). Further, just because an insecticide is organic does not mean that it is totally harmless; you should make sure that you are using the insecticide in the quantities and in the mechanism as directed. Also, be careful about the exact insecticide you are using.
Read this article for how to buy organic insecticides (link).