**4. Conclusion**

The insecticides of biological origin represent an asset but their major disadvantage in addition to their high costs, is their instability with storage. They quickly lose their effectiveness and consequently any competitiveness. But the need for both safe and natural food products while respecting nature and maintaining a healthy environment is a very important concept to be considered in Integrated Pest Management (IPM). IPM can be defined as a combination and the reasoned use of all the methods which makes it possible to control or to maintain the populations of pests to a threshold economically bearable. And if the consumers estimate that the products are of the first rate quality, they will not hesitate to pay for the full price. Finally, one can reach a great effectiveness in the improvement of plants protection by associating the conservation of auxiliary insects with the application of agrochemicals and biotechnology. Our developing countries will be able certainly to benefit from this progress.
