Using sand to prevent bugs in soil...?

I thought I read somewhere that one can use sand or some other material to prevent bugs in the soil. Anyone do this?
Thanks.

i have actualy thought about this......about pouring a inch or 2 of sand on top of my soil to help keep bugs away.....tho im not sure about it and im sure someone will come along and tell you not to do it cuz it will kill your plant or somethign like that.......i'v never tried it, but i would like more experienced comments on this mattter.....

I've used sand before to get rid of gnats. It worked great, the sharp edges kill off the larve. Just put a layer on top of the soil and it should work just fine. It won't hurt your plants any. Neem oil is another alternative. Organic and safe for plants.