It would really help to know where it is you live. Trees that bear the larger pecans do not do so well where I live, in the DFW (Texas) area. Native plants and trees do better wherever you are. Hybrids that do well here are "Kanza" and "Caddo". Check out the "Fruit and Pecan Tree Program":
http://www.dirtdoctor.com/pics/documents/ORGANIC%20PECAN%20AND%20FRUIT%20TREE%20PROGRAM.doc
The most common pecan tree pests can be controlled with the BOP:
http://www.dirtdoctor.com/pics/documents/bop.doc Good luck!