It is very important question, today, some nano-fertilizers are environmentally safe and scientists approved them for organic farming while others are not. So, more scientific research should be achieved to evaluate any negative or unknown effects for nano-fertilizers on environment.

I would suggest you contact the Canadian Fertilizer regulatory board for their findings concerning the regulation of nanomaterials. They have made nanomaterials a priority in registration of fertilizers, so there should be guidelines based on sound scientific research to assist you in identifying the core concerns with their application.

For a general answer to your question, consult the book "De A, Bose R, Kumar A, Mozumdar S. 2014. Targeted Delivery of Pesticides using

Biodegradable Polymeric Nanoparticles. New Delhi: Springer India."

For an application concerning microbial insecticide, see attached pdf.

All the best, Charles VINCENT