How Plants Repel Insects

Ever wonder why insects will feast on one plant in your garden and leave the others alone, or why your neighbor has a bug problem in his garden, and you don't (or vice versa).  An interesting recent article on Geoff Lawton's blog (Permaculture Research Institute of Australia) by permaculture student Oscar Morand sheds light on how this happens.  Insects can detect the plants with less nutrients and are programmed to prefer these, since they have simple digestive systems and are unable to process complex nutrients.  In fact, high plant nutrients will actually make insects sick according to Morand's sources (including Dr. Phillip Callahan of the University of Florida).