Enhancing the environmental soundness of agricultural practices, particularly in high input systems, is of increasing concern to those involved in agricultural research and development. The Integrated Pest Management Farmer Field School, which is based on farmer participatory environmental education, is compared to the No Early Spray intervention, which is a simple rule approach. A research methodology was developed and tested in the Philippines to document farmers' pre- and post-intervention knowledge of rice field insects, insect/plant interactions, and pesticides. The results indicate that increased knowledge from education is linked to better pest management behavior. It is proposed that the methodology may also be useful for documenting other areas of knowledge, in the design of educational interventions for farmers and in assessing their impact.